Biocryst Pharm, Inc (BCRX) - Description of business

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ITEM 1. BUSINESS

Forward-Looking Statements and Risk Factors

     This report includes forward-looking statements. In particular, statements about our expectations, beliefs, plans, objectives or assumptions of future events or performance are contained or incorporated by reference in this report. We have based these forward-looking statements on our current expectations about future events. While we believe these expectations are reasonable, forward-looking statements are inherently subject to risks and uncertainties, many of which are beyond our control. Our actual results may differ materially from those suggested by these forward-looking statements for various reasons, including those discussed in this report under the heading “Risk Factors” beginning at page 17. Given these risks and uncertainties, you are cautioned not to place undue reliance on forward-looking statements. The forward-looking statements included in this report are made only as of the date hereof. We do not undertake and specifically decline any obligation to update any of these statements or to publicly announce the results of any revisions to any forward looking statements to reflect future events or developments. When used in the report, unless otherwise indicated, “we,” “our” and “us” refers to BioCryst Pharmaceuticals, Inc.

Overview

     BioCryst Pharmaceuticals, Inc. is a biotechnology company that designs, optimizes and develops novel drugs that block key enzymes involved in cancer, cardiovascular diseases, autoimmune diseases, and viral infections. BioCryst integrates the necessary disciplines of biology, crystallography, medicinal chemistry and computer modeling to effectively use structure-based drug design to discover and develop small molecule pharmaceuticals.

     Our lead product candidate, Fodosine™, is a transition-state analog inhibitor of the target enzyme purine nucleoside phosphorylase (“PNP”). The compound is currently in a Phase IIb trial, which is planned to be a pivotal trial, for patients with T-cell acute lymphoblastic leukemia (“T-ALL”). The trial is being conducted under a special protocol assessment (“SPA”) negotiated with the U.S. Food and Drug Administration (“FDA”). Additionally, Fodosine™ is currently being studied in a Phase I/II trial with an oral formulation in cutaneous T-cell lymphoma (“CTCL”) and we are in active discussions with the FDA to determine what would be required to initiate a pivotal trial in CTCL during 2007. Fodosine™ has been granted Orphan Drug status by the FDA for three indications: T-cell non-Hodgkin’s lymphoma, including CTCL; chronic lymphocytic leukemia (“CLL”) and related leukemias including T-cell prolymphocytic leukemia, adult T-cell leukemia, and hairy cell leukemia; and for treatment of B-cell acute lymphoblastic leukemia (“B-ALL”). Additionally the FDA has granted “fast track” status to the development of Fodosine™ for the treatment of relapsed or refractory T-cell leukemia. In February 2006, we announced an exclusive licensing agreement with Mundipharma International Holdings Limited (“Mundipharma”) to develop and commercialize Fodosine™ in markets across Europe, Asia and Australasia for use in oncology.

     Our second most advanced drug candidate is peramivir, an inhibitor of influenza neuraminidase. We re-initiated clinical development of peramivir during 2006 with a focus on intravenous and intramuscular delivery. During 2006, we tested peramivir in multiple Phase I trials in healthy volunteers and early in 2007 we initiated a Phase II trial with the intramuscular formulation. In January 2007, we announced the U.S. Department of Health and Human Services (“HHS”) had awarded the Company a $102.6 million, four-year contract for the advanced development of peramivir. Funding from the contract will support manufacturing of clinical lots, process validation, clinical studies and other product approval requirements.

     In November 2005, the Company announced it had entered into an exclusive worldwide licensing agreement with F.Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc. (“Roche”) to develop and commercialize BCX-4208, our second generation PNP inhibitor for the prevention of acute rejection in transplantation and for the treatment of autoimmune diseases.

     BioCryst is a Delaware corporation originally founded in 1986. Our principal office is located at 2190 Parkway Lake Drive, Birmingham, Alabama 35244, and our telephone number is (205) 444-4600. For more information about BioCryst, please visit our website at www.biocryst.com. The information on our website is not incorporated into this Form 10-K.

Our Business Strategy

     Our business strategy is to use structure-based drug design technologies to develop innovative, small-molecule pharmaceuticals to treat a variety of diseases and disorders. We focus our drug discovery efforts on building potent, selective inhibitors of enzymes associated with targeted diseases. Enzymes are proteins that cause or enable biological reactions necessary for the progression of the disease or disorder. The specific enzymes on which we focus are called enzyme targets. We aim to design compounds that will inhibit an enzyme target by fitting the active site of a particular enzyme. Inhibition means interfering with the functioning of an enzyme target, thereby stopping or slowing the progression of the disease or disorder. The principal elements of our strategy are:


•   Select and License Promising Enzyme Targets for the Discovery of Small-Molecule Pharmaceuticals. We use our technical expertise and network of academic and industry contacts to evaluate and select promising enzyme targets to license for the discovery of small-molecule pharmaceuticals. We choose enzyme targets that meet as many of the following criteria as possible:

			–   serve important functions in disease pathways;
			–   have known animal or cell-based models that would be indicative of results in humans;
			–   address large potential markets or niche areas with significant unmet medical need; and
			–   have multiple potential clinical applications.

•		Focus on High Value-Added Structure-Based Drug Design Technologies. We focus our drug discovery activities and expenditures on applications of structure-based drug design technologies to design and develop drug candidates. Structure-based drug design is a process by which we design a drug candidate through detailed analysis of the enzyme target, which the drug candidate must inhibit in order to stop the progression of the disease or disorder. We believe that structure-based drug design is a powerful tool for efficient development of small-molecule drug candidates that have the potential to be safe, effective and relatively inexpensive to manufacture. Our structure-based drug design technologies typically allow us to design and synthesize multiple drug candidates that inhibit the same enzyme target. We believe this strategy can lead to broad patent protection and enhance the competitive advantages of our compounds.
•		Develop or License Inhibitors that are Promising Candidates for Commercialization. We test multiple compounds to identify those that are most promising for clinical development. We base our selection of promising development candidates on desirable product characteristics, such as initial indications of safety and efficacy. We believe that this focused strategy allows us to eliminate unpromising candidates from consideration sooner without incurring substantial clinical costs. In addition, we select drug candidates on the basis of their potential for relatively efficient Phase I and Phase II clinical trials that require fewer patients to initially indicate safety and efficacy. We will consider, however, more complex candidates with longer development cycles if we believe that they offer promising commercial opportunities.

     An important element of our business strategy is to control fixed costs and overhead through contracting and entering into license agreements with other parties. We maintain a streamlined corporate infrastructure that focuses on our strongest areas of expertise. By contracting with other specialty organizations, we believe that we can control costs, enable our drug candidates to reach the market more quickly and reduce our business risk. Key elements of our contracting strategy include:


•   Entering Into Relationships with Academic Institutions and Biotechnology Companies. Many academic institutions and biotechnology companies perform extensive research on the molecular and structural biology of potential drug development targets. By entering into relationships with these institutions, we believe we can leverage this respective research to significantly reduce the time, cost and risks involved in drug development. Our collaborative relationships with such organizations may lead to the licensing of one or more drug targets or compounds. Upon licensing a drug target or promising compound from one of these institutions, the scientists from

    the institution typically become working partners as members of our structure-based drug design teams. We believe this makes us a more attractive development partner to these scientists since they can continue to have some involvement in the continuing development of the program. In addition, we collaborate with outside experts in a number of areas, including crystallography, molecular modeling, combinatorial chemistry, biology, pharmacology, oncology, cardiology, immunology and infectious diseases. These collaborations enable us to complement our internal capabilities without adding costly overhead. We believe this strategy allows us to save valuable time and expense, and further diversify and strengthen our portfolio of drug candidates. An example of such a collaborative relationship is the arrangement that we have with Albert Einstein College of Medicine of Yeshiva University (“AECOM”) and Industrial Research Limited (“IRL”) who are the licensors of our PNP inhibitor programs.

•		Developing Drug Candidates or Licensing Them to Other Parties. We generally plan to advance drug candidates through initial and/or early-stage drug development. For larger disease indications requiring complex clinical trials, our strategy is to license drug candidates to pharmaceutical or biotechnology partners for final development and global marketing. We believe partnerships are a good source of development payments, license fees, future event payments and royalties. They also reduce the costs and risks, and increase the effectiveness, of late-stage product development, regulatory approval, manufacturing and marketing. We believe that focusing on discovery and early-stage drug development while benefiting from our partners’ proven development and commercialization expertise will reduce our internal expenses and allow us to have a larger number of drug candidates progress to later stages of drug development. However, after establishing a lead product candidate, we are willing to license that candidate during any stage of the development process we determine to be beneficial to the company and to the ultimate development and commercialization of that drug candidate. For some smaller niche disease indications markets, we may choose to develop, manufacture, and where appropriate market and distribute any approved drugs ourselves, such as Fodosine tm for certain T-cell and B-cell cancers in the U.S.
•		Entering into relationships with Contract Research Organizations (“CRO’s”). We outsource a significant portion of our R&D to third parties in order to avoid fixed overhead and remain focused on our core competencies. For example, we rely heavily on others to manufacture our products and on CRO’s for our clinical and regulatory operations. Using these vendors, we are able to capitalize on their strengths and expertise without having to build such infrastructure internally.

Products in Development

     The following table summarizes BioCryst’s most advanced projects as of February 28, 2007:

Program and Candidate Disease
Category/Indication		Delivery Form		Development Stage		Worldwide Rights
PNP Inhibitor (Fodosine™)
T-ALL		i.v./oral		Phase IIb		BioCryst/Mundipharma
CLL		oral		Phase II
B-ALL		i.v.		Phase I/II
CTCL		oral		Phase I/II
Neuraminidase Inhibitor (peramivir)		i.v.		Phase I		BioCryst
Viral		i.m.		Phase II
						Roche/BioCryst has
PNP Inhibitor (BCX-4208)						co-promotion rights
Autoimmune diseases						in the U.S. in
Transplantation rejection		oral		Phase I		limited indications
Hepatitis C Polymerase Inhibitors		oral		Preclinical		BioCryst
Viral

Additional Products

     In addition to the programs shown above, we also retain exclusive rights to potent inhibitors of parainfluenza neuraminidase and additional PNP inhibitors. We will continue to evaluate and test each of these compounds to determine which should be taken into clinical testing.

PNP Inhibitors

T-cell Related Diseases

      Overview . The human immune system employs specialized cells, including T-cells, to control infection by recognizing and attacking disease-causing viruses, bacteria and parasites. T-cells are an essential part of the body’s immune system that serve a dual purpose to both orchestrate and participate in the body’s immune response. For the most part, this system works flawlessly to protect the body. However, when T-cells multiply uncontrollably, T-cell proliferative diseases, such as T-cell cancers, can occur.

     The link between T-cell proliferation and the purine nucleoside phosphorylase, or PNP, enzyme was first discovered approximately twenty-five years ago when a patient, who was genetically deficient in PNP, exhibited limited T-cell activity, but reasonably normal activity of other immune functions. In other patients lacking PNP activity, the T-cell population was selectively depleted; however, B-cell function tended to be normal. Based on these findings and the results of cell culture studies, inhibiting PNP appears to produce selective suppression of T-cells without significantly impairing the function of other cells.

      Acute Lymphoblastic Leukemia . The most common form of leukemia in children is acute lymphoblastic leukemia (“ALL”). According to the American Cancer Society, 5,200 new cases (adult and children combined) will be diagnosed in the United States in 2007 (T-cell and B-cell). ALL results from an acquired injury to the DNA of a single cell in the bone marrow.

      T-cell Lymphoma . Lymphoma is a general term for a group of cancers that originate in the lymphatic system. About 63,190 Americans will be diagnosed with a non-Hodgkin’s lymphoma in 2007 and approximately 15% of these will be considered T-cell lymphomas. T-cell lymphoma results when a T-lymphocyte (a type of white blood cell) undergoes a malignant change and begins to multiply, eventually crowding out healthy cells and creating tumors, which enlarge the lymph nodes and invade other sites in the body. CTCL is a primary skin neoplasm and accounts for nearly 50% of all T-cell malignancies.

      T-cell Mediated Autoimmune Diseases. There are more than 80 clinically distinct autoimmune diseases such as psoriasis, rheumatoid arthritis, multiple sclerosis, and Crohn’s disease, which appear to have activated T-cells as a major part of their pathogenesis. These diseases occur when the immune system attacks the body’s own cells rather than invading microorganisms. Therefore, inhibition and/or elimination of activated T-cells could have a beneficial effect on these diseases.

      Transplant Rejection. The greatest threat to transplant patients is rejection of the transplanted organ by the body’s own immune system. For this reason, transplant recipients must take drugs to suppress the immune response and prevent rejection usually for the rest of their lives. A regimen combining several drugs is usually given and this treatment has to be continued indefinitely. For kidney transplant recipients, rejection of the new kidney by the patient’s immune system can lead to loss of the transplanted organ and a return to dialysis. For heart, lung and liver transplant patients, loss of the transplanted organ presents an immediate threat to life.

B-cell Related Cancers

      Overview . There are two types of lymphocytes in the broadest sense – T-cells and B-cells. Although PNP inhibitors were developed specifically to block the T-cells, recent work indicates that the same biochemical event – the intracellular accumulation of deoxyguanosine triphosphate (dGTP) also occurs in malignant B-cells. Furthermore, work of Dr. Varsha Gandhi at MD Anderson Cancer Center has shown that PNP inhibitors, when acting in vitro on B-cells from patients with CLL induce accumulation of dGTP with resultant apoptosis (cell death).

     These studies open the possibility of treating CLL, B-ALL and B-cell non-Hodgkin’s Lymphoma (NHL) with Fodosine. Importantly, B-cell malignancies are considerably more prevalent than are the T-cell leukemias and lymphomas.

Our PNP Inhibitor(s)

      PNP Inhibition . PNP is an enzyme that plays an important role in T-cell proliferation, because it is necessary to maintain normal DNA synthesis in human T-cells. Selective inhibition of PNP causes certain nucleosides, including deoxyguanosine, to accumulate. As the concentration of deoxyguanosine increases within T-cells, it is converted by specific enzymes to dGTP. A high concentration of dGTP in T-cells causes an imbalance in the intra-cellular trinucleotide pool and thus causes cell death.

     In June 2000, we licensed a series of potent PNP inhibitors from AECOM and IRL. The lead drug candidate from this collaboration, Fodosine™, is a more potent inhibitor of human lymphocyte proliferation than other previously known PNP inhibitors. Clinical data in our past and ongoing clinical trials, plus extensive preclinical studies indicate that Fodosine™ can modulate T-cell activities. Fodosine™ is an investigational PNP inhibitor for the potential treatment of T-cell leukemias and lymphomas. In February 2006, we licensed Fodosine™ to Mundipharma to develop and commercialize in markets across Europe, Asia and Australasia for use in oncology.

     During 2002, we exercised the option to add a new compound, BCX-4208, to the series of inhibitors of PNP licensed from AECOM and IRL. Preclinical results indicated that BCX-4208 was a more potent inhibitor than Fodosine™. We completed a Phase I single ascending dose clinical trial and a Phase Ib multi-dose clinical trial, both in healthy volunteers. In November 2005, we licensed BCX-4208 to Roche for the world wide development and commercialization in autoimmune diseases and transplant rejection.

PNP Inhibitor (Fodosine™)

Overview

     The first clinical trial with an intravenous formulation of Fodosine™, which began in 2002, was a Phase I clinical trial that enrolled T-ALL patients at the M.D. Anderson Cancer Center in Houston, Texas. Simultaneously, there were preclinical studies being conducted at the M.D. Anderson Cancer Center which indicated that Fodosine™ induces the same biochemical changes in various other types of leukemia cells that are responsible for the inhibition of T-leukemia cells. The results of these preclinical studies led us to expand beyond the single starting trial in T-ALL by initiating additional clinical trials for refractory patients with B-ALL, CTCL, and hematologic malignancies. Based on the encouraging results of these initial studies, we are working with our partner, Mundipharma, to develop a strategy for the simultaneous development of Fodosine™ in multiple indications using intravenous, oral and combination dosing regimens.

Current Development Strategy (T-ALL, CTCL, B-ALL, and CLL)

      Fodosine™ Clinical Development for Aggressive T-cell Malignancies . During 2004, we initiated a Phase IIa trial to enroll patients with aggressive T-cell malignancies. Despite encouraging results observed with other T-cell specific agents, the prognosis for patients with relapsed or refractory leukemia or lymphoma is poor and treatment options remain limited. The goal of the Phase IIa clinical trial was to determine the therapeutic effect produced by Fodosine™ as it relates to the proposed mechanism of action in the inhibition of proliferating T-lymphocytes in patients with T-ALL.

     Based on the results of the Phase IIa trial, we have negotiated a SPA agreement with the FDA for the design of a multicenter, open-label, non-randomized repeat-dose registration study to evaluate an intravenous treatment of Fodosine™ followed by an oral treatment of Fodosine™ in patients with relapsed or refractory T-ALL. This study is designed to determine the rate of complete remission achieved with Fodosine™ and will be a multinational trial which will include sites in the United States, Eastern and Western Europe and South America. We announced the start of this trial in January 2007.

     We have obtained orphan drug status for Fodosine™ in multiple indications in both the U.S. and Europe and the FDA has granted “fast track” status to the development of Fodosine™ for the treatment of relapsed or refractory T-cell leukemia. Our current intent is to maintain significant rights in this program and for BioCryst itself to potentially market and distribute Fodosine™ in the United States for treatment of T-cell cancers.

     In 2004, we initiated a Phase I/II trial with an oral formulation of Fodosine™ for treatment of patients with CTCL. Based on the encouraging results of this trial, we are in active discussions with the FDA to determine what would be required to initiate a pivotal trial in CTCL during 2007.

     In February 2006, we and Mundipharma entered into an exclusive license agreement to develop and commercialize Fodosine™, in markets across Europe, Asia and Australasia for use in oncology. The agreement covers a number of markets in Asia and Australasia including Japan, Australia, New Zealand, China and India. This collaboration should help maximize the global development, commercialization, and market potential of Fodosine™ in a variety of serious medical conditions potentially including T-cell leukemia, CTCL, CLL, T-cell non-Hodgkin’s lymphoma and B-cell non-Hodgkin’s lymphoma. Based on preclinical studies conducted at the M.D. Anderson Cancer Center which indicated that Fodosine™ induces the same biochemical changes in various other types of leukemia cells that are responsible for the inhibition of T-leukemia cells, we initiated two small clinical studies late in 2005 in B-cell leukemias, which are more prevalent than T-cell leukemias. First, we initiated a Phase II trial with oral Fodosine™ in patients with CLL in an advanced stage and refractory to fludarabine, the current standard of therapy. Next, we initiated a Phase I/II clinical trial of Fodosine™ to determine the safety of repeat doses of an intravenous (IV) formulation of the drug in patients with B-ALL. We are completing the evaluation of patients from these trials and are reviewing the results with Mundipharma to determine the best clinical strategy going forward.

PNP Inhibitor (BCX-4208)

Overview

     During the fourth quarter of 2004, we began clinical development of BCX-4208, a second-generation PNP inhibitor, as a drug candidate for the treatment of T-cell mediated autoimmune diseases, including psoriasis, and transplant rejection. Although BCX-4208 and Fodosine™ are both investigational PNP inhibitors, BCX-4208 differs from Fodosine™ in significant ways. For example, BCX-4208 is more potent, and has the ability to suppress PNP for longer periods of time. Thus, BCX-4208 has potential advantages over Fodosine™ for the treatment of diseases requiring long-term, chronic administration of a PNP inhibitor.

Current Development Strategy

     We completed our initial Phase I study, a single dose pharmacokinetic trial in healthy volunteers, early in 2005 and during the third quarter of 2005, we initiated a Phase Ib multi dose trial in healthy volunteers to evaluate the safety, tolerability, and pharmacokinetics of multiple oral doses of BCX-4208. In November 2005, we and Roche announced an exclusive license agreement for the worldwide development and commercialization of BCX-4208 for the prevention of acute rejection in transplantation and for the treatment of autoimmune diseases. This collaboration provided substantial strategic and economic benefit to us and also all the essential elements for the rapid, comprehensive and competitive development of BCX-4208. The two companies have established a joint committee to set the clinical development strategy and the future development program for BCX-4208.

     We completed the dosing of subjects in the Phase Ib trial during 2006 and we are currently working with Roche to plan the further development of BCX-4208 and anticipate that a Phase II trial will be initiated during 2007.

Neuraminidase Inhibitor

Influenza

      Seasonal Influenza. Seasonal influenza, commonly known as the flu, is a viral infection characterized by symptoms including fever, cough, sore throat, fatigue, headache, and/or chills. According to the U.S. Centers for Disease Control and Prevention (“CDC”), an estimated 5% to 20% of the American population suffers from influenza annually, more than 200,000 people are hospitalized from flu complications, and approximately 36,000 people die. Influenza is particularly dangerous to the elderly, young children and people with certain health conditions. Outbreaks of seasonal flu tend to follow predictable patterns usually occurring in the winter. New vaccines are developed annually based on known flu strains and are usually available for the annual flu season. There are also antiviral treatments available for the treatment of people infected with influenza.

      Avian Influenza . According to information from the CDC, avian influenza, or bird flu is an infection caused by viruses which occur naturally among birds. This form of flu is very contagious among birds and can lead to serious illness and sometimes death. There are two main forms of disease that infect domestic poultry, one a low pathogenic form and the other a highly pathogenic form. The latter form can cause disease that affects multiple internal organs and with a mortality rate between 90-100% in these birds within 2 days.

     While there are many different subtypes of the influenza A virus, only three subtypes are known to be currently circulating among humans. Avian influenza A viruses are found chiefly in birds, but there have been confirmed cases of infection in humans, generally as a result of contact with infected birds. These infections have led to symptoms ranging from those of normal flu to more severe and life threatening conditions. Influenza A (“H5N1”) is a subtype of an influenza virus that is highly contagious among birds and can be very deadly to them. Of the avian influenza viruses that have crossed the species barrier to infect humans, the H5N1 virus has caused the largest number of detected cases of severe disease and death in humans. Thus far, this virus does not spread easily from one person to another, but as influenza A viruses constantly change, they could mutate over time to have the ability to spread rapidly among humans.

      Pandemic Influenza . Pandemic influenza is a global disease outbreak that occurs when a new influenza virus emerges so that people have had no previous exposure. This situation occurs very rarely and only occurred three times in the 20 th century.

      Influenza Prevention and Treatment . The development of effective therapeutics has challenged medical researchers due to the seasonal variation in viral strains and the highly infectious nature of influenza. Patients, therefore, have limited treatment options. Amantadine and rimantadine are used for treatment of influenza A but are ineffective against influenza B. In addition, these drugs cause some adverse side effects, and the virus tends to develop resistance to these drugs. The CDC has recommended against the use of amantadine and rimantadine for the treatment or prophylaxis of influenza in the United States until susceptibility to these antiviral medications has been re-established among circulating influenza A viruses.

     Vaccines are available against the disease but have limitations: people require advance vaccination; vaccines are limited by their specificity to particular strains of the virus; and vaccines offer little protection if the vaccine is inaccurate. In addition, many people decline the required injections because of fear and/or discomfort. The ability of the virus to change its structure to avoid the body’s natural defenses is a serious obstacle to developing an effective vaccine against influenza. Different strains can arise when surface antigens on the virus (the portion of the virus that causes an immune reaction in humans) undergo minor genetic mutations each year as the virus replicates. Because of this mutability, the immunity acquired in response to infection by a particular strain of the virus does not provide adequate protection against viruses that subsequently arise. The production of a new vaccine each year is not only complex and expensive, but also an inefficient method of global disease control.

      Inhibiting Influenza Neuraminidase. Research during the past two decades has seen dramatic advances in understanding the molecular structure and function of the influenza virus. Considerable attention has been focused on the enzyme neuraminidase, which is located on the surface of the virus. Neuraminidase assists in the release and spread of the flu virus by breaking the chemical strands that hold the new viruses to the cell surface, allowing the replicated virus to spread and infect other cells. This process progresses until the host’s immune response can produce enough antibodies to bring the infection under control. Inhibiting the neuraminidase enzyme keeps new viruses attached to the cell surface, thereby preventing the spread of the virus and the further infection of other cells. The subsequent quantities of virus in the bloodstream are not enough to cause disease but are sufficient to induce the body to mount an immune response.

     In addition to our neuraminidase inhibitor drug candidate, both Roche, in collaboration with Gilead Sciences, and GlaxoSmithKline (“GSK”) have neuraminidase inhibitors. Roche’s neuraminidase inhibitor is a twice-a-day, orally active neuraminidase inhibitor, while GSK’s neuraminidase inhibitor is administered by dry powder inhaler twice a day. Both drugs are approved for marketing in the United States and other countries for treatment of influenza. Roche’s neuraminidase inhibitor is also approved for prophylaxis use for prevention of influenza. In addition to these companies with neuraminidase inhibitors, there are other companies working to develop additional antiviral drugs to be used against various strains of influenza.

     Some studies in laboratories suggest that some of these neuraminidase inhibitor drugs should work in treating avian influenza infections in humans, but additional studies are needed to demonstrate the effectiveness of these drugs.

Neuraminidase Inhibitor (peramivir)

Overview

      Background. In 1987, scientists at The University of Alabama at Birmingham (“UAB”), in collaboration with our scientists, began determining the molecular structure of the influenza neuraminidase enzyme from several different strains of influenza, using X-ray crystallography. Subsequently, our scientists and UAB scientists developed numerous new inhibitors of these enzymes using structure-based drug design. We licensed the influenza neuraminidase program from UAB in 1994 and proceeded to complete the studies of the enzyme’s molecular structure needed to advance the development of neuraminidase inhibitors. The structure of the active site of influenza neuraminidase is similar among different viral strains. Because of this similarity, we believe that our neuraminidase inhibitors may be effective in the treatment and prevention of influenza, regardless of changes in the virus.

      Current status of peramivir. Due to the recent international concern about a potential influenza pandemic that could be initiated by avian strains of the virus, peramivir has received considerable attention, since it is positioned to be one of very few advanced antiviral alternatives behind oseltamivir, or Tamiflu, for addressing a potential pandemic. As a result, we re-initiated the clinical development of peramivir during 2006.

Current Development Strategy

     Preclinical studies comparing peramivir with other anti-influenza drugs have demonstrated that peramivir has outstanding broad-spectrum potency against multiple strains of influenza, including the avian strain H5N1. In addition, peramivir retains activity against nearly all Tamiflu-resistant strains of influenza that have been identified to date. We are currently focusing on injectable formulations of peramivir that may achieve high blood levels that should be effective against most strains of influenza, including strains that may be resistant to Tamiflu. Our investigational new drug application (“IND”) for i.v. peramivir became effective in December 2005 and for i.m. in November 2006. We received fast track designation from the FDA in January 2006 and initiated a Phase I clinical trial with i.v. peramivir in March 2006. During 2006, we conducted multiple Phase I clinical trials in healthy volunteers in preparation for the Phase II trials to be initiated during the 2006-2007 influenza season, which began with the initiation of a Phase II study with the i.m. formulation in January 2007.

     Our plan is to develop two injectable formulations, including intravenous peramivir for treating acutely ill patients, and an intramuscular injectable formulation for treatment of earlier-stage infected patients. We expect the clinical development for these injectable formulations to follow a classical development pathway. Initial testing in patients infected with seasonal flu began with the initiation of the Phase II study with the i.m. formulation in January 2007. Preclinical studies have indicated that a single injection of peramivir is effective at preventing death in mice from infections with virulent strains of influenza. If this finding can be confirmed in clinical trials, we believe the i.m. formulation will have considerable potential for treating patients with seasonal influenza infections, in addition to providing an effective mechanism for treating large numbers of patients rapidly in the event of a flu pandemic.

     Congress approved an appropriation of $3.8 billion for 2006 to support the development of various countermeasures for a flu pandemic. The appropriation included funding for the development of new antiviral agents. In January 2007, we announced that HHS had awarded the Company a $102.6 million, four-year contract for the advanced development of peramivir for U.S. licensure. Funding from the contract will support manufacturing of clinical lots, process validation, clinical studies and other product approval requirements needed for U.S. licensure.

Hepatitis C Polymerase Inhibitors

Overview

     Hepatitis C virus (“HCV”) infection has been described in the New England Journal of Medicine as the nation’s most common chronic blood-borne infection. According to the World Health Organization, 3% of the world’s population are infected with HCV and are at risk of developing liver cirrhosis and/or liver cancer. The CDC estimates there are an estimated 4.1 million Americans (approximately 1.6% of the population) that have been infected with HCV,

of whom 3.2 million are chronically infected. According to the CDC, as many as 55-85% of those infected with HCV will have chronic infection and 70% of those will develop chronic liver disease. While there are several approved treatments for chronic HCV using a combination therapy of interferon and ribavirin, there are some potentially severe side effects to these treatments.

      Background . In June 2000, we licensed intellectual property from Emory University (“Emory”) related to the hepatitis C polymerase target associated with hepatitis C viral infections. Under the original terms of the agreement, the research investigators from Emory provided us with materials and technical insight into the target.

Current Development Strategy

     We are targeting HCV polymerase through collaborative and in-house efforts. Specifically, we are focused on development of orally active inhibitors against the RNA-dependent RNA polymerase. Competition for this target is less intense than for the HCV protease target and history suggests the likelihood of designing a useful inhibitor against this target may be better than designing inhibitors against the protease.

     We have designed, synthesized and screened potential compounds against HCV polymerase. Specifically, our scientists have measured the potency and ability of potential drug candidates to block the replication of HCV polymerase in vitro, or in test tubes. These experiments measure the potency of each selected compound’s ability to block replication. Advanced screening was also used to measure the fit of promising compounds in the HCV polymerase active site using X-ray crystallography and computer molecular modeling. The goal has been to identify a series of compounds that are potent in vitro inhibitors of the active site of the HCV polymerase for further testing and lead optimization.

     During 2005, we identified a lead compound, BCX-4678, for which we have made progress in the preclinical development, plus major improvements in the large-scale synthesis. In addition, we have identified a number of other preclinical candidates for this therapeutic area and we are currently evaluating and prioritizing which candidate(s) to bring into clinical development.

Structure-Based Drug Design

     Structure-based drug design is a drug discovery approach by which we design synthetic compounds from detailed structural knowledge of the active sites of enzyme targets associated with particular diseases. Enzymes are proteins that act as catalysts for many vital biological reactions. Our goal generally is to design a compound that will fit in the active site of an enzyme (the active site of an enzyme is the area into which a chemical or biological molecule fits to initiate a biochemical reaction) and thereby interfere with the progression of disease.

     Our structure-based drug design involves the application of both traditional biology and medicinal chemistry and an array of advanced technologies. We use X-ray crystallography, computer modeling of molecular structures and advanced chemistry techniques to focus on the three-dimensional molecular structure and active site characteristics of the enzymes that control cellular biology.

     We believe that structure-based drug design technologies are superior to drug screening techniques. By identifying the target enzyme in advance and by discovering the chemical and molecular structure of the enzyme, we believe it is possible to design a better drug to interact with the enzyme. In addition, the structural data obtained by X-ray crystallographic analysis allow additional analysis and compound modification at each stage of the biological evaluation. This capability makes structure-based drug design a powerful tool for efficient development of drugs that are highly specific for particular enzyme target sites.

Research and Development

     We initiated our research and development program in 1986, with drug synthesis beginning in 1987. We have assembled a scientific research staff with expertise in a broad base of advanced research technologies including protein biochemistry, X-ray crystallography, chemistry and pharmacology. Our research facilities include protein biochemistry and organic synthesis laboratories, testing facilities, X-ray crystallography, computer and graphics equipment and facilities to make drug candidates on a small scale for early stage clinical trials. Beginning in June 2006, we began

building an internal clinical development and regulatory team, based in Cary, North Carolina to manage the development strategy for our products.

     During the years ended December 31, 2006, 2005 and 2004, we spent $47.1, $23.6 and $18.9 million, respectively, on research and development. Approximately $13.4, $9.1 and $8.0 million of those respective amounts were spent on in-house research and development, and $33.7, $14.5 and $10.9 million, respectively were spent on contract research and development.

Collaboration and In-License Relationships

     We seek to enter into collaborations with leading pharmaceutical and biotechnology companies when we feel it is advantageous to leverage these companies’ resources to develop and commercialize our drug candidates on a global basis. This allows us to remain focused on our strength of early stage discovery and development of drug candidates. To date, we have two major collaborations for the development and commercialization of our lead PNP inhibitors and two collaborations for the development and commercialization of peramivir in certain countries outside the U.S. In addition, in January 2007, we announced that HHS had awarded the Company a $102.6 million, four-year contract for the advanced development of peramivir for U.S. licensure.

     Another important component of our strategy is to augment our internal discovery programs through the selective in-licensing of potential drug development targets or early stage compounds for these specific targets.

Corporate Alliances

      Roche . In November 2005, we entered into an exclusive license with Roche for the development and commercialization of our second generation PNP inhibitor, BCX-4208, for the prevention of acute rejection in transplantation and for the treatment of autoimmune diseases. Under the terms of the agreement, Roche obtained worldwide rights to BCX-4208 in exchange for an up-front payment of $30 million, which included a payment as reimbursement for a limited supply of material during the first 24 months of the collaboration. There could also be future event payments for achieving specified development, regulatory and commercial milestones (including sales level milestones following a product’s launch) for certain indications. In addition, we will receive royalties based on a percentage of net product sales, which varies depending upon when certain indications receive NDA approval in a major market country and can vary by country depending on the patent coverage or sales of generic compounds in a particular country. We licensed this compound and other PNP inhibitors from AECOM and IRL and will owe sublicense payments to these third parties on the upfront payment, future event payments and royalties received by us for the sublicense of these inhibitors.

     Roche has a right of first negotiation, under certain conditions, on existing backup PNP inhibitors we develop through Phase IIb in transplant rejection and autoimmune diseases, but any new PNP inhibitors are exempt from this agreement and we retain all rights to such compounds. We retain the right to co-promote BCX-4208 in the U.S. for several indications. Roche has certain obligations under the terms of the agreement to use commercially reasonable efforts to develop, manufacture and commercialize the licensed product. The agreement may be terminated by either party following an uncured material breach by the other party or may be either fully or partially terminated by Roche without cause under certain conditions and all rights, data, materials, products and other information would be transferred to us at no cost.

      Mundipharma . In February 2006, we entered into an exclusive, royalty bearing right and license in the specified territory (primarily Europe, Asia and Australasia) with Mundipharma for the development and commercialization of our lead PNP inhibitor, Fodosine™, for use in oncology. Under the terms of the agreement, Mundipharma obtained oncology rights to Fodosine™ in the specified territory in exchange for a $10 million up-front payment. Mundipharma will share 50% of the documented out of pocket development costs incurred by us in respect of our current and planned trials as of the effective date of the agreement provided that Mundipharma’s maximum contribution to these trials shall be $10 million. In addition, Mundipharma will conduct additional clinical trials at their own cost up to a maximum of $15 million. The license provides for future event payments for achieving specified development, regulatory and commercial events (including certain sales level amounts following a product’s launch) for certain indications. In addition, we will receive royalties based on a percentage of net product sales, which varies depending upon when certain indications receive NDA approval in a major market country and can vary by country depending on the patent

coverage or sales of generic compounds in a particular country. Generally, all payments under the agreement are nonrefundable and non-creditable, but they are subject to audit. We licensed this compound and other PNP inhibitors from AECOM and IRL and will owe sublicense payments to these third parties on the upfront payment, future event payments and royalties received by us for the sublicense of these inhibitors.

     Within five years of the effective date of the agreement, Mundipharma will has a right of first negotiation on existing backup PNP inhibitors we develop through Phase IIb in oncology, but any new PNP inhibitors are exempt from this agreement and we retain all rights to such compounds. We retain the rights to Fodosine™ in the United States (“U.S.”) and Mundipharma is obligated by the terms of the agreement to use commercially reasonable efforts to develop the licensed product in the territory specified by the agreement. The agreement will continue for the commercial life of the licensed products, but may be terminated by either party following an uncured material breach by the other party or in the event the pre-existing third party license with AECOM and IRL expires. It may be terminated by Mundipharma upon 60 days written notice without cause or under certain other conditions as specified in the agreement and all rights, data, materials, products and other information would be transferred to us at no cost. In the event we terminate the agreement for material default or insolvency, we could have to pay Mundipharma 50% of the costs of any independent data owned by Mundipharma in accordance with the terms of the agreement.

      Shionogi & Co., Ltd. In March 2007, the Company entered into an exclusive license agreement with Shionogi & Co., Ltd. (“Shionogi”) to develop and commercialize the Company’s lead influenza neuraminidase inhibitor, peramivir, in Japan for the treatment of seasonal and potentially life-threatening human influenza. Under the terms of the agreement, Shionogi obtained rights to injectable formulations of peramivir in Japan in exchange for a $14 million up-front payment. The license provides for future event payments for achieving specified development, regulatory and commercial events (including certain sales level amounts following a product’s launch) for certain indications. In addition, the Company will receive royalties based on a percentage of net product sales. Generally, all payments under the agreement are nonrefundable and non-creditable, but they are subject to audit. The Company developed peramivir under a license from UAB and will owe sublicense payments to them on the upfront payment and any future event payments and/or royalties received by the Company from Shionogi. The Company retains all rights to commercialize peramivir in North America, Europe, and other countries outside of Korea and Japan.

      Green Cross Corporation (“Green Cross”). In June 2006, the Company entered into an agreement with Green Cross to develop and commercialize peramivir in Korea. Under the terms of the agreement, Green Cross will be responsible for all development, regulatory, and commercialization costs in Korea. The Company received a one-time license fee and may also receive future event payments as well as royalties on product sales of peramivir. In addition, the Company will share in any profits resulting from the sale of peramivir to the Korean government for stockpiling purposes. Furthermore, Green Cross will pay the Company a premium over its cost to supply peramivir for development and any future marketing of peramivir products in Korea.

Academic Alliances

      Albert Einstein College of Medicine of Yeshiva University and Industrial Research, Ltd, New Zealand . In June 2000, we licensed a series of potent inhibitors of PNP from AECOM and IRL. The lead drug candidates from this collaboration are Fodosine™ and BCX-4208. We have obtained worldwide exclusive rights to develop and ultimately distribute these compounds or any other drug candidates that might arise from research on these inhibitors. We have agreed to pay certain milestone payments for future development of these inhibitors, certain royalties on sales of any resulting product, and to share in future payments received from other third-party partners, if any. In addition, we have agreed to pay an annual license fee that is non-refundable, but is creditable against actual royalties and other payments due to AECOM and IRL. This agreement may be terminated by us at any time by giving 60 days advance notice or in the event of material uncured breach by AECOM and/or IRL.

      The University of Alabama at Birmingham . We have had a close relationship with UAB since our formation. Our Chairman, Dr. Charles E. Bugg, was the previous Director of the UAB Center for Macromolecular Crystallography, and our President and Chief Operating Officer, Dr. J. Claude Bennett, was the former President of UAB, the former Chairman of the Department of Medicine at UAB and a former Chairman of the Department of Microbiology at UAB. Several of our early programs originated at UAB.

     We currently have agreements with UAB for influenza neuraminidase and complement inhibitors. Under the terms of these agreements, UAB performed specific research for us in return for research payments and license fees. UAB has granted us certain rights to any discoveries in these areas resulting from research developed by UAB or jointly developed with us. We have agreed to pay royalties on sales of any resulting product and to share in future payments received from other third-party partners. We have completed the research under both the complement and influenza agreements. These two agreements have initial 25-year terms, are automatically renewable for five-year terms throughout the life of the last patent and are terminable by us upon three months notice and by UAB under certain circumstances. There is currently no activity between us and UAB on these agreements, but when the Company licenses this technology, such as in the case of the Shionogi and Green Cross agreements, or commercialize products related to these programs, we will owe sublicense fees or royalties on amounts we receive.

      Emory . In June 2000, we licensed intellectual property from Emory related to the HCV polymerase target associated with hepatitis C viral infections. Under the original terms of the agreement, the research investigators from Emory provided us with materials and technical insight into the target. We have agreed to pay Emory royalties on sales of any resulting product and to share in future payments received from other third party partners, if any. We can terminate this agreement at any time by giving 90 days advance notice.

Government Contracts

     In January 2007, we announced that HHS had awarded the Company a $102.6 million, four-year contract for the advanced development of peramivir for U.S. licensure. Funding from the contract will support manufacturing of clinical lots, process validation, clinical studies and other product approval requirements needed for U.S. licensure. HHS has indicated that antiviral drugs are an important element of their pandemic influenza preparedness efforts and that their strategy includes not only stockpiling of existing antiviral drugs but also seeking out new antiviral medications to further broaden their capabilities to treat and prevent all forms of influenza. Peramivir is in the same class of neuraminidase inhibitors as oseltamivir (Tamiflu) and zanamivir (Relenza), all of which are antiviral drugs, but the method of delivery for peramivir will be parenteral (i.m. and i.v.) as compared to the oral Tamiflu or inhaled Relenza. We are committed to working with HHS for the development of these parenteral formulations of peramivir which could be especially useful in hospital settings or pandemic situations due to the ability to achieve high levels of the drug rapidly throughout the body.

     This contract is a cost-plus-fixed-fee contract, which is milestone-driven. HHS will make periodic assessments of progress and the continuation of the contract is based on our performance, timeliness and quality of deliverables, and other factors. The government has rights under certain contract clauses to terminate this contract.

Patents and Proprietary Information

     Our success will depend in part on our ability to obtain and enforce patent protection for our products, methods, processes and other proprietary technologies, preserve our trade secrets, and operate without infringing on the proprietary rights of other parties, both in the United States and in other countries. We own or have rights to certain proprietary information, proprietary technology, issued and allowed patents and patent applications which relate to compounds we are developing. We actively seek, when appropriate, protection for our products, proprietary technology and proprietary information by means of U.S. and foreign patents, trademarks and contractual arrangements. In addition, we rely upon trade secrets and contractual arrangements to protect certain of our proprietary information, proprietary technology and products.

     The patent positions of companies like ours are generally uncertain and involve complex legal and factual questions. Our ability to maintain and solidify our proprietary position for our technology will depend on our success in obtaining effective patent claims and enforcing those claims once granted. We do not know whether any of our patent applications or those patent applications that we license will result in the issuance of any patents. Our issued patents and those that may issue in the future, or those licensed to us, may be challenged, invalidated, rendered unenforceable or circumvented, which could limit our ability to stop competitors from marketing related products or the length of term of patent protection that we may have for our products. In addition, the rights granted under any issued patents may not provide us with competitive advantages against competitors with similar compounds or technology. Furthermore, our competitors may independently develop similar technologies or duplicate any technology developed by us in a manner that does not infringe our patents or other intellectual property. Because of the extensive time required for development, testing and regulatory review of a potential product, it is possible that, before any of our drug candidates or those

developed by our partners can be commercialized, any related patent may expire or remain in force for only a short period following commercialization, thereby reducing any advantage of the patent.

     As of February 20, 2007, we have been issued 28 U.S. patents that expire between 2009 and 2023 and that relate to our PNP, serine protease and neuraminidase inhibitor compounds. We have licensed six additional composition of matter patents and two pending composition of matter patents from AECOM and IRL for our PNP inhibitors, plus additional manufacturing patents related to these PNP inhibitors and one patent from Emory related to hepatitis C. Additionally, we have 16 U.S. patent applications pending related to PNP, neuraminidase, RNA viral polymerase, paramyxovirus neuraminidase, and serine protease inhibitors. Our pending applications may not result in issued patents, and our patents may not provide us with sufficient protection against competitive products or otherwise be commercially viable.

     Our success is also dependent upon the skills, knowledge and experience of our scientific and technical personnel, none of which is patentable. To help protect our rights, we require all employees, consultants, advisors and partners to enter into confidentiality agreements, which prohibit the disclosure of confidential information to anyone outside of our company and, where possible, requires disclosure and assignment to us of their ideas, developments, discoveries and inventions. These agreements may not provide adequate protection for our trade secrets, know-how or other proprietary information in the event of any unauthorized use or disclosure or the lawful development by others of such information.

Marketing and Sales

     We currently plan to market, distribute and sell Fodosine™ in the U.S. for use in treatment of T-cell and B-cell cancers. Although our general strategy is to rely on major marketing companies for worldwide commercialization of most products we may develop, we believe that we can manage the highly specialized oncology market for Fodosine™ within the U.S. Most patients with advanced T-cell malignancies in the U.S. are treated at major referral cancer centers, and many of these centers have been participating in our Fodosine™ clinical trials and will thus be familiar with Fodosine™ if it reaches the market. However, we lack experience in marketing, distributing and selling pharmaceutical products. Our general strategy is to rely on partners, licensees or arrangements with others to provide for the marketing, distribution and sales of products we may develop. We may not be able to establish and maintain acceptable commercial arrangements with partners, licensees or others to perform such activities.

Competition

     The pharmaceutical and biotechnology industries are intensely competitive. Many companies, including biotechnology, chemical and pharmaceutical companies, are actively engaged in activities similar to ours, including research and development of drugs for the treatment of cancer, infectious, autoimmune, inflammatory and cardiovascular diseases and disorders. Many of these companies have substantially greater financial and other resources, larger research and development staffs, and more extensive marketing and manufacturing organizations than we do. In addition, some of them have considerable experience in preclinical testing, clinical trials and other regulatory approval procedures. For example, in October 2005, the FDA announced the approval of Arranon (nelarabine) for the treatment of adults and children with T-cell acute lymphoblastic leukemia. This drug was approved under the FDA’s orphan drug and accelerated approval (fast track) programs and is being distributed and marketed by GSK. We are currently testing Fodosine™ in T-cell ALL and have also received both orphan drug and fast track designation from the FDA. There are also academic institutions, governmental agencies and other research organizations that are conducting research in areas in which we are working. They may also market commercial products, either on their own or through collaborative efforts.

     We expect to encounter significant competition for any of the pharmaceutical products we plan to develop. Companies that complete clinical trials, obtain required regulatory approvals and commence commercial sales of their products before their competitors may achieve a significant competitive advantage. Such is the case with GSK’s Arranon for T-cell ALL and the current neuraminidase inhibitors marketed by GSK and Roche for influenza. In addition, several pharmaceutical and biotechnology firms, including major pharmaceutical companies and specialized structure-based drug design companies, have announced efforts in the field of structure-based drug design and in the fields of PNP, HCV, influenza, and other therapeutic areas where we are focusing our drug discovery efforts.

     In order to compete successfully, we must develop proprietary positions in patented drugs for therapeutic markets that have not been satisfactorily addressed by conventional research strategies and, in the process, expand our expertise in structure-based drug design. Our products, even if successfully tested and developed, may not be adopted by physicians over other products and may not offer economically feasible alternatives to other therapies.

Government Regulation

     The FDA regulates the pharmaceutical and biotechnology industries in the U.S., and our drug candidates are subject to extensive and rigorous domestic government regulations prior to commercialization. The FDA regulates, among other things, the development, testing, manufacture, safety, efficacy, record-keeping, labeling, storage, approval, advertising, promotion, sale and distribution of pharmaceutical products. In foreign countries, our products are also subject to extensive regulation by foreign governments. These government regulations will be a significant factor in the production and marketing of any pharmaceutical products that we develop. Failure to comply with applicable FDA and other regulatory requirements at any stage during the regulatory process may subject us to sanctions, including:

	•		delays;
	•		warning letters;
	•		fines;
	•		product recalls or seizures;
	•		injunctions;
	•		penalties;
	•		refusal of the FDA to review pending market approval applications or supplements to approval applications;
	•		total or partial suspension of production;
	•		civil penalties;
	•		withdrawals of previously approved marketing applications; and
	•		criminal prosecutions.

     The regulatory review and approval process is lengthy, expensive and uncertain. Before obtaining regulatory approvals for the commercial sale of any products, we or our partners must demonstrate that our product candidates are safe and effective for use in humans. The approval process takes many years, substantial expenses may be incurred and significant time may be devoted to clinical development.

     Before testing potential candidates in humans, we carry out laboratory and animal studies to determine safety and biological activity. After completing preclinical trials, we must file an IND, including a proposal to begin clinical trials, with the FDA. We have filed thirteen INDs to date and plan to file, or rely on future partners to file, additional INDs in the future as our potential drug candidates advance to that stage of development. Thirty days after filing an IND, a Phase I human clinical trial can start, unless the FDA places a hold on the study.

     Our Phase I trials are designed to determine safety in a small group of patients or healthy volunteers. We also assess tolerances and the metabolic and pharmacologic actions of our drug candidates at different doses. After we complete the initial trials, we conduct Phase II trials to assess safety and efficacy and establish the optimal dose in patients. If Phase II trials are successful, we or our partners conduct Phase III trials to verify the results in a larger patient population. Phase III trials are required for FDA approval to market a drug. A Phase III trial may require hundreds or even thousands of patients and is the most expensive to conduct. The goal in Phase III is to collect enough safety and efficacy data to obtain FDA approval of a drug for treatment of a particular disease. For some clinical indications that are

especially serious and for which there are no effective treatments, such as refractory cancers, conditional approval can be obtained following Phase II trials.

     Initiation and completion of the clinical trial phases are dependent on several factors including things that are beyond our control. For example, the clinical trials cannot begin at a particular site until that site receives approval from its Institutional Review Board (“IRB”), which reviews the protocol and related documents. This process can take from several weeks to several months. In addition, clinical trials are dependent on patient enrollment, but the rate at which patients enroll in the study depends on:

	•		willingness of investigators to participate in a study;
	•		ability of clinical sites to obtain approval from their IRB;
	•		the size of the patient population we intend to treat;
	•		the availability of patients;
	•		the willingness of patients to participate; and
	•		the patients meeting the eligibility criteria.

     Delays in planned patient enrollment may result in increased expense and longer development timelines.

     After completion of the clinical trials of a product, we or our partners must submit a NDA to the FDA for marketing approval before commercialization of the product. The FDA may not grant approval on a timely basis, if at all. The FDA, as a result of the Food and Drug Administration Modernization Act of 1997, has six months to review and act upon license applications for priority therapeutics that are for life-threatening or unmet medical needs. Standard reviews can take between one and two years, and can even take longer if significant questions arise during the review process. The FDA may withdraw any required approvals, once obtained.

     In addition to clinical development regulations, we and our contract manufacturers and partners must comply with the applicable FDA current good manufacturing practice (“GMP”) regulations. GMP regulations include requirements relating to quality control and quality assurance as well as the corresponding maintenance of records and documentation. Manufacturing facilities are subject to inspection by the FDA. Such facilities must be approved before we can use them in commercial manufacturing of our potential products. We or our contract manufacturers may not be able to comply with the applicable GMP requirements and other FDA regulatory requirements. If we or our contract manufacturers fail to comply, our business, financial condition and results of operations will be materially adversely affected.

Human Resources

     As of February 28, 2007, we had 85 employees, of whom 61 were engaged in research and development and 24 were in general and administrative functions. Our scientific staff, 28 of whom hold Ph.D. or M.D. degrees, has diversified experience in biochemistry, pharmacology, X-ray crystallography, synthetic organic chemistry, computational chemistry, and medicinal chemistry. We consider our relations with our employees to be satisfactory.

Scientific Advisory Board and Consultants

     Our scientific advisory board (“SAB”) is comprised of five scientific advisors who are leaders in certain of our core disciplines or who otherwise have specific expertise in our therapeutic focus areas. The SAB meets as a group at scheduled meetings and consists of the following individuals:

Name		Position
Albert F. LoBuglio, M.D. (Chairman)		Director Emeritus and Distinguished Professor, Comprehensive Cancer Center , University Of Alabama at Birmingham

Name		Position
Gordon N. Gill, M.D.		Professor of Medicine and Cellular and Molecular Medicine; Dean of Translational Medicine, University of California, San Diego School of Medicine.
Lorraine J. Gudas, Ph.D.		Professor and Chairman, Department of Pharmacology Weill Medical College of Cornell University, Revlon Pharmaceutical Professor of Pharmacology and Toxicology.
Herbert A. Hauptman, Ph.D.		President of the Hauptman-Woodward Medical Research Institute, Inc. (formerly the Medical Foundation (Buffalo), Inc.), and Research Professor in Biophysical Sciences and Distinguished Professor in Structural Biology at the State University of New York (Buffalo). Recipient of the Nobel Prize in Chemistry (1985).
Hamilton O. Smith, M.D.		Professor, Molecular Biology and Genetics Department at The Johns Hopkins University School of Medicine, retired, and Scientific Director of the Synthetic Biology and Biological Energy Groups at the J. Craig Venter Institute in Rockville, Maryland. Recipient of the Nobel Prize in Medicine (1978).

     The SAB members are reimbursed for their expenses and receive periodic options to purchase shares of common stock. We also have consulting agreements with a number of other scientists with expertise in our core disciplines or who are specialists in diseases or treatments on which we focus. The SAB members and other consultants are all employed by or have consulting agreements with entities other than us, some of which may compete with us in the future. They are expected to devote only a small portion of their time to our business, although no specific time commitment has been established. They are not expected to participate actively in our affairs or in the development of our technology. Several of the institutions with which the SAB members and the consultants are affiliated may adopt new regulations or policies that limit their ability to consult with us. The loss of the services of the SAB members and the consultants could adversely affect us to the extent that we are pursuing research or development in areas relevant to their expertise. To the extent members of our SAB members or the consultants have consulting arrangements with or become employed by any of our competitors, we could be materially adversely affected.

     Any inventions or processes independently discovered by the SAB members or the consultants may not become our property and will probably remain the property of such persons or of such persons’ employers. In addition, the institutions with which they are affiliated may make available the research services of their personnel, including the SAB members and the consultants, to our competitors pursuant to sponsored research agreements. We require the SAB members and the consultants to enter into confidentiality agreements which prohibit the disclosure of confidential information to anyone outside of our company and require disclosure and assignment to us of their ideas, developments, discoveries or inventions. However, our competitors may gain access to trade secrets and other proprietary information developed by us and disclosed to the SAB members and the consultants.

Available Information

     We have available a website on the Internet. Our address is www.biocryst.com. We make available at our website our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. We also make available at our website copies of our audit committee charter, compensation committee charter, corporate governance and nominating committee charter and our code of business conduct, which applies to all employees of BioCryst as well as the members of our Board of Directors.

ITEM 1A. RISK FACTORS

      An investment in our stock involves a high degree of risk. You should consider carefully the following risks, along with all of the other information included in our other filings with the Securities and Exchange Commission, before deciding to buy our common stock. Additional risks and uncertainties not currently known to us or that we currently deem to be immaterial may also impair our business operations. If we are unable to prevent events that have a negative effect from occurring, then our business may suffer. Negative events are likely to decrease our revenue, increase our costs, make our financial results poorer and/or decrease our financial strength, and may cause our stock price to decline. In that case, you may lose all or a part of your investment in our common stock.

Risks Relating to Our Business

We have incurred substantial losses since our inception in 1986, expect to continue to incur such losses, and may never be profitable.

     Since our inception in 1986, we have not been profitable. We expect to incur additional losses for the foreseeable future, and our losses could increase as our research and development efforts progress. As of December 31, 2006, our accumulated deficit was approximately $195.5 million. To become profitable, we must successfully develop drug product candidates, enter into profitable agreements with other parties and our product candidates must receive regulatory approval. We or these other parties must then successfully manufacture and market our product candidates. It could be several years, if ever, before we receive royalties from any current or future license agreements or revenues directly from product sales.

     Because of the numerous risks and uncertainties associated with developing our product candidates and their potential for commercialization, we are unable to predict the extent of any future losses or when we will become profitable, if at all. Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. If we are unable to achieve and sustain profitability, the market value of our common stock will likely decline.

Our success depends upon our ability to advance our products through the various stages of development, especially through the clinical trial process.

     To receive the regulatory approvals necessary for the sale of our product candidates, we or our partners must demonstrate through preclinical studies and clinical trials that each product candidate is safe and effective. The clinical trial process is complex and uncertain. Because of the cost and duration of clinical trials, we may decide to discontinue development of product candidates that are unlikely to show good results in the trials, unlikely to help advance a product to the point of a meaningful collaboration, or unlikely to have a reasonable commercial potential. We may suffer significant setbacks in pivotal clinical trials, even after earlier clinical trials show promising results. Any of our product candidates may produce undesirable side effects in humans. These side effects could cause us or regulatory authorities to interrupt, delay or halt clinical trials of a product candidate. These side effects could also result in the FDA or foreign regulatory authorities refusing to approve the product candidate for any targeted indications. We, our partners, the FDA or foreign regulatory authorities may suspend or terminate clinical trials at any time if we or they believe the trial participants face unacceptable health risks. Clinical trials may fail to demonstrate that our product candidates are safe or effective.

     Our ability to successfully complete clinical trials is dependent upon many factors beyond our control, including:

	•		our ability to find suitable clinical sites and investigators to enroll patients;
	•		the availability of and willingness of patients to participate in our clinical trials;
	•		difficulty in maintaining contact with patients to provide complete data after treatment;
	•		our product candidates may not prove to be either safe or effective;

	•		manufacturing or quality problems could affect the supply of drug product for our trials;
	•		delays or changes in requirements by governmental agencies.

     Clinical trials are lengthy and expensive. We or our partners incur substantial expense for, and devote significant time to, preclinical testing and clinical trials, yet cannot be certain that the tests and trials will ever result in the commercial sale of a product. For example, clinical trials require adequate supplies of drug and sufficient patient enrollment. Delays in patient enrollment can result in increased costs and longer development times. Even if we or our partners successfully complete clinical trials for our product candidates, we or our partners might not file the required regulatory submissions in a timely manner and may not receive regulatory approval for the product candidate.

If we fail to obtain additional financing, we may be unable to complete the development and commercialization of our product candidates or continue our research and development programs.

     To date, we have financed our operations primarily from sale of our equity securities and cash from collaborative and other research and development agreements, and, to a lesser extent, interest. For the year, our cash, cash equivalents and marketable securities balance has decreased from $60.0 million as of December 31, 2005 to $46.2 million as of December 31, 2006, primarily due to the monthly cash burn from operations less the cash received from collaborations, which totaled to approximately $31.8 million net of sublicense fees.

     With the award of the HHS contract to fund the development of peramivir and the current and planned trials for Fodosine™, we expect an increase in our operating expenses for 2007. However, with the expected reimbursement from the HHS contract and our other partners, we are projecting our net cash burn rate to average approximately $3.0 million per month in 2007. We caution that both our expenses and our cash flows will vary significantly from quarter to quarter due to the nature of the trials in influenza and the reimbursement from HHS.

     As our clinical programs continue to grow and patient enrollment increases, our costs will increase. Our current and planned clinical trials plus the related manufacturing, personnel resources and testing required for supporting the development of our drug candidates will consume significant capital resources and will increase our expenses. Our expenses, revenues and burn rate could vary significantly depending on many factors, including our ability to raise additional capital, the development progress of our collaborative agreements for our drug candidates, the amount of funding we receive from HHS for peramivir, the amount of funding or assistance, if any, we receive from other governmental agencies or other new partnerships with third parties for the development of our drug candidates, the progress and results of our current and proposed clinical trials for our most advanced drug products, the progress made in the manufacturing of our lead products and the progression of our other programs.

     As of December 31, 2006, we had $46.2 million in cash, cash equivalents and marketable securities. With our currently available funds and amounts to be received from HHS, Shionogi (and our other collaborators), we believe these resources will be sufficient to fund our operations for at least the next twelve months. However, this is a forward looking statement, and there may be changes that would consume available resources significantly before such time. Our long-term capital requirements and the adequacy of our available funds will depend upon many factors, including:

	•		our ability to perform under the contract with HHS and receive reimbursement;
	•		the progress and magnitude of our research, drug discovery and development programs;
	•		changes in existing collaborative relationships or government contracts;
	•		our ability to establish additional collaborative relationships with academic institutions, biotechnology or pharmaceutical companies and governmental agencies or other third parties;
	•		the extent to which our partners, including governmental agencies will share in the costs associated with the development of our programs or run the development programs themselves;
	•		our ability to negotiate favorable development and marketing strategic alliances for our drug candidates;

	•		the scope and results of preclinical studies and clinical trials to identify and evaluate drug candidates;
	•		our ability to enroll sites and patients in our clinical trials;
	•		the scope of manufacturing of our drug candidates to support our preclinical research and clinical trials;
	•		increases in personnel and related costs to support the development of our drug candidates;
	•		the scope of validation for the manufacturing of our drug substance and drug products required for future NDA filings;
	•		competitive and technological advances;
	•		the time and costs involved in obtaining regulatory approvals;
	•		the costs involved in preparing, filing, prosecuting, maintaining and enforcing patent claims;
	•		our dependence on others for development and commercialization of our product candidates; and
	•		successful commercialization of our products consistent with our licensing strategy.

     We expect that we will be required to raise additional capital to complete the development and commercialization of our current product candidates. Additional funding, whether through additional sales of securities or collaborative or other arrangements with corporate partners or from other sources, including governmental agencies, in general and from the HHS contract specifically, may not be available when needed or on terms acceptable to us. The issuance of preferred or common stock or convertible securities, with terms and prices significantly more favorable than those of the currently outstanding common stock, could have the effect of diluting or adversely affecting the holdings or rights of our existing stockholders. In addition, collaborative arrangements may require us to transfer certain material rights to such corporate partners. Insufficient funds may require us to delay, scale-back or eliminate certain of our research and development programs.

If HHS were to eliminate or reduce funding from our contract, this would have a significant negative impact on our anticipated revenues and cash flows and the development of peramivir.

     Our projections of revenues and incoming cash flows for 2007 are substantially dependant upon HHS reimbursement for the costs related to our peramivir program. If HHS were to eliminate or reduce the funding for this program, we would have to obtain additional funding for development of this drug candidate or significantly reduce or stop the development effort.

     In contracting with HHS, we are subject to various U.S. government contract requirements, including general clauses for a cost-reimbursement research and development contract, which may limit our reimbursement or if we are found to be in violation could result in contract termination. U.S. government contracts typically contain unfavorable termination provisions and are subject to audit and modification by the government at its sole discretion. The U.S. government may terminate its contract with us either for its convenience or if we default by failing to perform in accordance with the contract schedule and terms, which would have a significant negative impact on our cash flows and operations.

Our contract with HHS has special contracting requirements, which create additional risks or reduction or loss of funding.

     We have entered into a contract with HHS for the advanced development of our neuraminidase inhibitor, peramivir. In contracting with HHS, we are subject to various U.S. government contract requirements, including general clauses for a cost-reimbursement research and development contract. U.S. government contracts typically contain unfavorable termination provisions and are subject to audit and modification by the government at its sole discretion, which subjects us to additional risks. These risks include the ability of the U.S. government to unilaterally:

	•		terminate or reduce the scope of our contract; and
	•		audit and object to our contract-related costs and fees, including allocated indirect costs.

     The U.S. government may terminate its contract with us either for its convenience or if we default by failing to perform in accordance with the contract schedule and terms. Termination for convenience provisions generally enable

us to recover only our costs incurred or committed, and settlement expenses and profit on the work completed prior to termination. Termination for default provisions do not permit these recoveries.

     As a U.S. government contractor, we are required to comply with applicable laws, regulations and standards relating to our accounting practices and are subject to periodic audits and reviews. As part of any such audit or review, the U.S. government may review the adequacy of, and our compliance with, our internal control systems and policies, including those relating to our purchasing, property, estimating, compensation and management information systems. Based on the results of its audits, the U.S. government may adjust our contract-related costs and fees, including allocated indirect costs. In addition, if an audit or review uncovers any improper or illegal activity, we may be subject to civil and criminal penalties and administrative sanctions, including termination of our contracts, forfeiture of profits, suspension of payments, fines and suspension or prohibition from doing business with the U.S. government. We could also suffer serious harm to our reputation if allegations of impropriety were made against us. In addition, under U.S. government purchasing regulations, some of our costs may not be reimbursable or allowed under our contracts. Further, as a U.S. government contractor, we are subject to an increased risk of investigations, criminal prosecution, civil fraud, whistleblower lawsuits and other legal actions and liabilities as compared to private sector commercial companies.

If we fail to establish collaborative relationships to commercialize certain of our drug product candidates or if any partner terminates or fails to perform its obligations under agreements with us, the commercialization of our product candidates could be delayed or terminated.

     A key aspect of our business strategy is to enter into successful collaborative arrangements with pharmaceutical companies, research institutions, the United States government and universities for the preclinical development, clinical development, regulatory approval, marketing, domestic and international sales and distribution of our drug product candidates. Our general strategy is to rely upon other parties for all of these steps so that we can focus exclusively on the key areas of our expertise. For some smaller niche markets, we may perform these steps ourselves and outsource those functions where we do not have the internal expertise.

     Currently, we have established collaborative relationships with four pharmaceutical companies, Roche, Mundipharma, Shionogi and Green Cross for development and commercialization of BCX-4208, Fodosine™ and peramivir, respectively. The process of establishing and implementing collaborative relationships is difficult, time-consuming and involves significant uncertainty. Heavy reliance upon collaborative relationships with these third parties for these critical functions presents several risks, including:

	•		our partners may seek to renegotiate or terminate their relationships with us due to unsatisfactory clinical results, a change in business strategy, a change of control or other reasons;
	•		our contracts for collaborative arrangements may expire;
	•		our partners may choose to pursue alternative technologies, including those of our competitors;
	•		we may have disputes with a partner that could lead to litigation or arbitration;
	•		we do not have day to day control over the activities of our partners and have limited control over their decisions;
	•		our ability to generate future event payments and royalties from our partners depends upon their abilities to establish the safety and efficacy of our drug candidates, obtain regulatory approvals and achieve market acceptance of products developed from our drug candidates;
	•		our partners may not properly maintain or defend our intellectual property rights, where applicable, or they may utilize our proprietary information in such a way as to invite litigation that could jeopardize or potentially invalidate our proprietary information or expose us to potential liability;
	•		our partners may not devote sufficient capital or resources towards our product candidates; and
	•		our partners may not comply with applicable government regulatory requirements.

     If any partner fails to fulfill its responsibilities in a timely manner, or at all, our commercialization efforts related to that collaboration could be delayed or terminated, or it may be necessary for us to assume responsibility for activities that would otherwise have been the responsibility of our partner. If we are unable to establish and maintain collaborative relationships on acceptable terms, we may have to delay or discontinue further development of one or more of our product candidates, undertake commercialization activities at our own expense or find alternative sources of funding. Any delay in the development or commercialization of our compounds would severely affect our business, because if our compounds do not progress through the development process or reach the market in a timely manner, or at all, we may not receive additional future event payments and may never receive product or royalty payments.

If our contract research organizations do not successfully carry out their duties or if we lose our relationships with contract research organizations, our drug development efforts could be delayed.

     We depend on contract research organizations, third-party vendors and investigators for preclinical testing and clinical trials related to our drug discovery and development efforts, including the HHS contract. We intend to depend on them to assist in our future discovery and development efforts. These parties are not our employees and we cannot control the amount or timing of resources that they devote to our programs. If they fail to devote sufficient time and resources to our drug development programs or if their performance is substandard, it will delay the approval of our products. The parties with which we contract for execution of our clinical trials play a significant role in the conduct of the trials and the subsequent collection and analysis of data. Their failure to meet their obligations could adversely affect clinical development of our products. Moreover, these parties may also have relationships with other commercial entities, some of which may compete with us. If they assist our competitors it could harm our competitive position.

     If we lose our relationship with any one or more of these parties, we could experience a significant delay in both identifying another comparable provider and then contracting for its services. We may be unable to retain an alternative provider on reasonable terms, if at all. Even if we locate an alternative provider, it is likely that this provider may need additional time to respond to our needs and may not provide the same type or level of service as the original provider. In addition, any provider that we retain will be subject to current Good Laboratory Practices (“cGLP”), current Good Manufacturing Practices (“cGMP”), or current Good Clinical Practices (“cGCP”), and similar foreign standards and we do not have control over compliance with these regulations by these providers. Consequently, if these practices and standards are not adhered to by these providers, the development and commercialization of our product candidates could be delayed.

We have not commercialized any products or technologies and our future revenue generation is uncertain.

     We have not yet commercialized any products or technologies, and we may never be able to do so. Our revenue from collaborative agreements is dependent upon the status of our preclinical and clinical programs. If we fail to advance these programs to the point of being able to enter into successful collaborations, we will not receive any future event or other collaborative payments.

     Any future revenue directly from product sales would depend on our ability to successfully complete clinical studies, obtain regulatory approvals, manufacture, market and commercialize any approved drugs.

If our development collaborations with other parties fail, the development of our drug product candidates will be delayed or stopped.

     We rely heavily upon other parties for many important stages of our drug development programs, including:

	•		discovery of proteins that cause or enable biological reactions necessary for the progression of the disease or disorder, called enzyme targets;
	•		licensing or design of enzyme inhibitors for development as drug product candidates;
	•		execution of some preclinical studies and late-stage development for our compounds and product candidates;
	•		management of our clinical trials, including medical monitoring and data management;

	•		execution of additional toxicology studies that may be required to obtain approval for our product candidates;
	•		manufacturing the starting materials and drug substance required to formulate our drug products and the drug products to be used in both our clinical trials and toxicology studies;
	•		management of our regulatory function; and
	•		manufacturing, sales, marketing and distribution of our product candidates.

     Our failure to engage in successful collaborations at any one of these stages would greatly impact our business. If we do not license enzyme targets or inhibitors from academic institutions or from other biotechnology companies on acceptable terms, our product development efforts would suffer. Similarly, if the contract research organizations that conduct our initial or late-stage clinical trials, conduct our toxicology studies, manufacture our starting materials, drug substance and drug products or manage our regulatory function breached their obligations to us, this would delay or prevent the development of our product candidates.

Our development of both intravenous and intramuscular dosing of peramivir for avian flu is subject to all disclosed drug development and potential commercialization risks and numerous additional risks. Any potential revenue benefits to us are highly speculative.

     Further development and potential commercialization of peramivir is subject to all the risks and uncertainties disclosed in our other risk factors relating to drug development and commercialization. In addition, potential commercialization of peramivir is subject to further risks, including the following:

	•		the injectable versions of peramivir are at an early stage of development and have been tested in a limited number of humans, primarily healthy volunteers, and may not be safe or effective;
	•		necessary government or other third party funding and clinical testing for further development of peramivir may not be available timely, at all, or in sufficient amounts;
	•		the avian flu prevention or treatment concerns may not materialize at all, or in the near future;
	•		advances in flu vaccines could substantially replace potential demand for an antiviral such as peramivir;
	•		any substantial demand for avian flu treatments may occur before peramivir can be adequately developed and tested in clinical trials;
	•		numerous large and well-established pharmaceutical and biotech companies will be competing to meet the market demand for avian flu drugs and vaccines;
	•		regulatory authorities may not make needed accommodations to accelerate the drug testing and approval process for peramivir; and
	•		in the next few years, it is expected that a limited number of governmental entities will be the primary potential customers for peramivir and if we are not successful at marketing peramivir to these entities for any reason, we will not receive substantial revenues.

     If any or all of these and other risk factors occur, we will not attain significant revenues or gross margins from peramivir and our stock price will be adversely affected.

Because we have limited manufacturing experience, we depend on third-party manufacturers to manufacture our drug product candidates and the materials for our product candidates. If we cannot rely on third-party manufacturers, we will be required to incur significant costs and potential delays in finding new third-party manufacturers.

     We have limited manufacturing experience and only a small scale manufacturing facility. We currently rely upon third-party manufacturers to manufacture the materials required for our drug product candidates and most of the preclinical and clinical quantities of our product candidates. We depend on these third-party manufacturers to perform their obligations in a timely manner and in accordance with applicable governmental regulations. Our third-party manufacturers may encounter difficulties with meeting our requirements, including problems involving:

	•		inconsistent production yields;
	•		difficulties in scaling production to commercial and validation sizes;
	•		interruption of the delivery of materials required for the manufacturing process;
	•		scheduling of plant time with other vendors or unexpected equipment failure;
	•		potential catastrophes that could strike their facilities;
	•		poor quality control and assurance or inadequate process controls; and
	•		lack of compliance with regulations and specifications set forth by the FDA or other foreign regulatory agencies.

     These contract manufacturers may not be able to manufacture the materials required or our drug product candidates at a cost or in quantities necessary to make them commercially viable. We also have no control over whether third-party manufacturers breach their agreements with us or whether they may terminate or decline to renew agreements with us. To date, our third party manufacturers have met our manufacturing requirements, but they may not continue to do so. Furthermore, changes in the manufacturing process or procedure, including a change in the location where the drug is manufactured or a change of a third-party manufacturer, may require prior review and approval in accordance with the FDA’s cGMPs, and comparable foreign requirements. This review may be costly and time-consuming and could delay or prevent the launch of a product. The FDA or similar foreign regulatory agencies at any time may also implement new standards, or change their interpretation and enforcement of existing standards for manufacture, packaging or testing of products. If we or our contract manufacturers are unable to comply, we or they may be subject to regulatory action, civil actions or penalties.

     If we are unable to enter into agreements with additional manufacturers on commercially reasonable terms, or if there is poor manufacturing performance on the part of our third party manufacturers, we may not be able to complete development of, or market, our product candidates.

     Our raw materials, drug substances, and drug products are manufactured by a limited group of suppliers and some at a single facility. If any of these suppliers were unable to produce these items, this could significantly impact our supply of drugs for further preclinical testing and clinical trials.

If the clinical trials of our drug product candidates fail, our product candidates will not be marketed, and we will not realize product related revenue.

     To receive the regulatory approvals necessary for the sale of our product candidates, we or our partners must demonstrate through preclinical studies and clinical trials that each product candidate is safe and effective. If we or other third party partners are unable to demonstrate that our product candidates are safe and effective, our product candidates will not receive regulatory approval and will not be marketed, and we will not realize product related

revenue. The clinical trial process is complex and uncertain. Because of the cost and duration of clinical trials, we may decide to discontinue development of product candidates that are unlikely to show good results in the trials, unlikely to help advance a product to the point of a meaningful collaboration, or unlikely to have a reasonable commercial potential. Positive results from preclinical studies and early clinical trials do not ensure positive results in clinical trials designed to permit application for regulatory approval, called pivotal clinical trials. We may suffer significant setbacks in pivotal clinical trials, even after earlier clinical trials show promising results. Any of our product candidates may produce undesirable side effects in humans. These side effects could cause us or regulatory authorities to interrupt, delay or halt clinical trials of a product candidate. These side effects could also result in the FDA or foreign regulatory authorities refusing to approve the product candidate for any targeted indications. We, our partners, the FDA or foreign regulatory authorities may suspend or terminate clinical trials at any time if we or they believe the trial participants face unacceptable health risks. Clinical trials may fail to demonstrate that our product candidates are safe or effective.

     We negotiated a special protocol assessment, or SPA, with the FDA for the recently initiated pivotal clinical trial of our lead anti-cancer compound, Fodosine™. An SPA is an agreement between an applicant and the FDA on the design and the size of clinical trials that is intended to form the basis of a New Drug Application (“NDA”). Once the FDA and an applicant reach an agreement on an SPA, the SPA cannot be changed after the clinical trial begins, except in limited circumstances such as a change in the science or clinical knowledge about the conditions being studied. Any significant change to the protocols for a clinical trial subject to an SPA would require prior FDA approval, which could delay implementation of such a change and continuation and completion of the related clinical trial. Receipt of the SPA does not ensure that Fodosine™ will receive FDA approval or that the process will be accelerated.

     Clinical trials are lengthy and expensive. We or our partners incur substantial expense for, and devote significant time to, preclinical testing and clinical trials, yet cannot be certain that the tests and trials will ever result in the commercial sale of a product. For example, clinical trials require adequate supplies of drug and sufficient patient enrollment. Delays in patient enrollment can result in increased costs and longer development times. Even if we or our partners successfully complete clinical trials for our product candidates, we or our partners might not file the required regulatory submissions in a timely manner and may not receive regulatory approval for the product candidate.

If we or our partners do not obtain and maintain governmental approvals for our products under development, we or our partners will not be able to sell these potential products, which would significantly harm our business because we will receive no revenue.

     We or our partners must obtain regulatory approval before marketing or selling our future drug products. If we or our partners are unable to receive regulatory approval and do not market or sell our future drug products, we will never receive any revenue from such product sales. In the United States, we or our partners must obtain FDA approval for each drug that we intend to commercialize. The FDA approval process is typically lengthy and expensive, and approval is never certain. Products distributed abroad are also subject to foreign government regulation. Neither the FDA nor foreign regulatory agencies have approved any of our drug product candidates. We have several drug products in various stages of preclinical and clinical development; however, we are unable to determine when, if ever, any of these products will be commercially available. Because of the risks and uncertainties in biopharmaceutical development, our product candidates could take a significantly longer time to gain regulatory approval than we expect or may never gain approval. If the FDA delays regulatory approval of our product candidates, our management’s credibility, our company’s value and our operating results may suffer. Even if the FDA or foreign regulatory agencies approve a product candidate, the approval may limit the indicated uses for a product candidate and/or may require post-marketing studies.

     The FDA regulates, among other things, the record keeping and storage of data pertaining to potential pharmaceutical products. We currently store most of our preclinical research data, our clinical data and our manufacturing data at our facility. While we do store duplicate copies of most of our clinical data offsite and a significant portion of our data is included in regular backups of our systems, we could lose important data if our facility incurs damage. If we get approval to market our potential products, whether in the United States or internationally, we will continue to be subject to extensive regulatory requirements. These requirements are wide ranging and govern, among other things:

 
•   adverse drug experience reporting regulations;

	•		product promotion;
	•		product manufacturing, including good manufacturing practice requirements; and
	•		product changes or modifications.

     Our failure to comply with existing or future regulatory requirements, or our loss of, or changes to, previously obtained approvals, could have a material adverse effect on our business because we will not receive product or royalty revenues if we or our partners do not receive approval of our products for marketing.

     In June 1995, we notified the FDA that we submitted incorrect data for our Phase II studies of BCX-34 applied to the skin for CTCL and psoriasis. In November 1995, the FDA issued a List of Inspectional Observations, Form FDA 483, which cited our failure to follow good clinical practices. The FDA also inspected us in June 1996. The focus was on the two 1995 Phase II dose-ranging studies of topical BCX-34 for the treatment of CTCL and psoriasis. As a result of the investigation, the FDA issued us a Form FDA 483, which cited our failure to follow good clinical practices. We are no longer developing BCX-34; however, as a consequence of these two investigations, our ongoing and future clinical studies may receive increased scrutiny, which may delay the regulatory review process.

If our drug product candidates do not achieve broad market acceptance, our business may never become profitable.

     Our drug product candidates may not gain the market acceptance required for us to be profitable even if they successfully complete initial and final clinical trials and receive approval for sale by the FDA or foreign regulatory agencies. The degree of market acceptance of any product candidates that we or our partners develop will depend on a number of factors, including:

	•		our clinical evidence of safety and efficacy;
	•		cost-effectiveness, convenience and ease of use of our product candidates;
	•		their safety, availability and effectiveness relative to alternative treatments;
	•		the actual and potential side effects or other reactions;
	•		reimbursement policies of government and third-party payers; and
	•		the effectiveness of marketing and distribution support for our product candidates.

     Physicians, patients, payers or the medical community in general may not accept or use our product candidates even after the FDA or foreign regulatory agencies approve the drug candidates. If our product candidates do not achieve significant market acceptance, we will not have enough revenues to become profitable.

We face intense competition, and if we are unable to compete effectively, the demand for our products, if any, may be reduced.

     The biotechnology and pharmaceutical industries are highly competitive and subject to rapid and substantial technological change. We face, and will continue to face, competition in the licensing of desirable disease targets, licensing of desirable drug product candidates, and development and marketing of our product candidates from academic institutions, government agencies, research institutions and biotechnology and pharmaceutical companies. Competition may also arise from, among other things:

	•		other drug development technologies;
	•		methods of preventing or reducing the incidence of disease, including vaccines; and
	•		new small molecule or other classes of therapeutic agents.

     Developments by others may render our product candidates or technologies obsolete or noncompetitive.

     We and our partners are performing research on or developing products for the treatment of several disorders including T-cell mediated disorders (T-cell cancers, psoriasis, transplant rejection, and rheumatoid arthritis), oncology, influenza, hepatitis C and cardiovascular disorders. We expect to encounter significant competition for any of the pharmaceutical products we plan to develop. Companies that complete clinical trials, obtain required regulatory approvals and commence commercial sales of their products before their competitors may achieve a significant competitive advantage. Such is the case with GSK’s Arranon for T-cell ALL and the current neuraminidase inhibitors marketed by GSK and Roche for influenza. In addition, several pharmaceutical and biotechnology firms, including major pharmaceutical companies and specialized structure-based drug design companies, have announced efforts in the field of structure-based drug design and in the fields of PNP, influenza, hepatitis C, and in other therapeutic areas where we have discovery efforts ongoing. If one or more of our competitors’ products or programs are successful, the market for our products may be reduced or eliminated.

     Compared to us, many of our competitors and potential competitors have substantially greater:

	•		capital resources;
	•		research and development resources, including personnel and technology;
	•		regulatory experience;
	•		preclinical study and clinical testing experience;
	•		manufacturing and marketing experience; and
	•		production facilities.

     Any of these competitive factors could reduce demand for our products.

If we fail to adequately protect or enforce our intellectual property rights or secure rights to patents of others, the value of those rights would diminish.

     Our success will depend in part on our ability and the abilities of our partners to obtain patent protection for our products, methods, processes and other technologies we may license or develop, to preserve our trade secrets, and to operate without infringing the proprietary rights of third parties both domestically and abroad. The patent position of biotechnology and pharmaceutical companies is generally highly uncertain, involves complex legal and factual questions and has recently been the subject of much litigation. Neither the United States Patent and Trademark Office (“USPTO”) nor the courts have a consistent policy regarding the breadth of claims allowed or the degree of protection afforded under many biotechnology and pharmaceutical patents. The validity, enforceability and commercial value of these rights, therefore, is highly uncertain.

     Our success depends in part on avoiding the infringement of other parties’ patents and proprietary rights as well as avoiding the breach of any licenses relating to our technologies and products. In the U.S., patent applications filed in recent years are confidential for 18 months, while older applications are not published until the patent issues. As a result, avoiding patent infringement may be difficult and we may inadvertently infringe third-party patents or proprietary rights. These third parties could bring claims against us, our partners or our licensors that even if resolved in our favor, could cause us to incur substantial expenses and, if resolved against us, could additionally cause us to pay substantial damages. Further, if a patent infringement suit were brought against us, our partners or our licensors, we or they could be forced to stop or delay research, development, manufacturing or sales of any infringing product in the country or countries covered by the patent we infringe, unless we can obtain a license from the patent holder. Such a license may not be available on acceptable terms, or at all, particularly if the third party is developing or marketing a product competitive with the infringing product. Even if we, our partners or our licensors were able to obtain a license, the rights may be nonexclusive, which would give our competitors access to the same intellectual property.

     If we or our partners are unable to adequately protect or enforce our intellectual property rights for our products, methods, processes and other technologies, the value of the drug product candidates that we license to derive revenue would diminish. Additionally, if our products, methods, processes and other technologies infringe the proprietary rights of other parties, we could incur substantial costs. The USPTO has issued to us a number of U.S. patents for our various inventions and we have in-licensed several patents from various institutions. We have filed additional patent applications and provisional patent applications with the USPTO. We have filed a number of corresponding foreign patent applications and intend to file additional foreign and U.S. patent applications, as appropriate. We cannot assure you as to:

	•		the degree and range of protection any patents will afford against competitors with similar products;
	•		if and when patents will issue; or
	•		whether or not others will obtain patents claiming aspects similar to those covered by our patent applications.

     If the USPTO upholds patents issued to others or if the USPTO grants patent applications filed by others, we may have to:

	•		obtain licenses or redesign our products or processes to avoid infringement;
	•		stop using the subject matter claimed in those patents; or
	•		pay damages.

     We may initiate, or others may bring against us, litigation or administrative proceedings related to intellectual property rights, including proceedings before the USPTO. Any judgment adverse to us in any litigation or other proceeding arising in connection with a patent or patent application could materially and adversely affect our business, financial condition and results of operations. In addition, the costs of any such proceeding may be substantial whether or not we are successful.

     Our success is also dependent upon the skills, knowledge and experience, none of which is patentable, of our scientific and technical personnel. To help protect our rights, we require all employees, consultants, advisors and partners to enter into confidentiality agreements that prohibit the disclosure of confidential information to anyone outside of our company and require disclosure and assignment to us of their ideas, developments, discoveries and inventions. These agreements may not provide adequate protection for our trade secrets, know-how or other proprietary information in the event of any unauthorized use or disclosure or the lawful development by others of such information, and if any of our proprietary information is disclosed, our business will suffer because our revenues depend upon our ability to license our technology and any such events would significantly impair the value of such a license.

If we fail to retain our existing key personnel or fail to attract and retain additional key personnel, the development of our drug product candidates and the expansion of our business will be delayed or stopped.

     We are highly dependent upon our senior management and scientific team, the loss of whose services might impede the achievement of our development and commercial objectives. Competition for key personnel with the experience that we require is intense and is expected to continue to increase. Our inability to attract and retain the required number of skilled and experienced management, operational and scientific personnel, will harm our business because we rely upon these personnel for many critical functions of our business. In addition, we rely on members of our scientific advisory board and consultants to assist us in formulating our research and development strategy. All of the members of the scientific advisory board and all of our consultants are otherwise employed and each such member or consultant may have commitments to other entities that may limit their availability to us.

We may be unable to establish sales, marketing and distribution capabilities necessary to successfully commercialize products we may develop.

     We currently have no marketing capability and no direct or third-party sales or distribution capabilities. If we successfully develop a drug product candidate and decide to commercialize it ourselves rather than relying on third parties, as we are considering doing in the United States for Fodosine™, we may be unable to establish marketing, sales and distribution capabilities necessary to commercialize and gain market acceptance for that product.

If users of our drug products are not reimbursed for use, future sales of our drug products will decline.

     The lack of reimbursement for the use of our product candidates by hospitals, clinics, patients or doctors will harm our business. Medicare, Medicaid, health maintenance organizations and other third-party payers may not authorize or otherwise budget for the reimbursement of our products. Governmental and third-party payers are increasingly

challenging the prices charged for medical products and services. We cannot be sure that third-party payers would view our product candidates as cost-effective, that reimbursement will be available to consumers or that reimbursement will be sufficient to allow our product candidates to be marketed on a competitive basis. Changes in reimbursement policies, or attempts to contain costs in the health care industry could limit or restrict reimbursement for our product candidates and would materially and adversely affect our business, because future product sales would decline and we would receive less product or royalty revenue.

The Medicare prescription drug coverage legislation and future legislative or regulatory reform of the healthcare system may affect our ability to sell our products profitably.

     In the United States, there have been a number of legislative and regulatory proposals, at both the federal and state government levels, to change the healthcare system in ways that could affect our ability to sell our products profitably, if approved. For example, the Medicare Prescription Drug and Modernization Act of 2003 (“MMA”), went into effect in 2006 and has changed the types of drugs covered by Medicare, and the methodology used to determine the price for such drugs. Further federal and state proposals and healthcare reforms are likely. Our business could be harmed by the MMA, by the possible effect of this legislation on amounts that private payors will pay and by other healthcare reforms that may be enacted or adopted in the future.

There is a substantial risk of product liability claims in our business. If we are unable to obtain sufficient insurance, a product liability claim against us could adversely affect our business.

     We face an inherent risk of product liability exposure related to the testing of our product candidates in human clinical trials and will face even greater risks upon any commercialization by us of our product candidates. We have product liability insurance covering our clinical trials in the amount of $10 million. Clinical trial and product liability insurance is becoming increasingly expensive. As a result, we may be unable to obtain sufficient insurance or increase our existing coverage at a reasonable cost to protect us against losses that could have a material adverse effect on our business. An individual may bring a product liability claim against us if one of our products or product candidates causes, or is claimed to have caused, an injury or is found to be unsuitable for consumer use. Any product liability claim brought against us, with or without merit, could result in:

	•		liabilities that substantially exceed our product liability insurance, which we would then be required to pay from other sources, if available;
	•		an increase of our product liability insurance rates or the inability to maintain insurance coverage in the future on acceptable terms, or at all;
	•		withdrawal of clinical trial volunteers or patients;
	•		damage to our reputation and the reputation of our products, resulting in lower sales;
	•		regulatory investigations that could require costly recalls or product modifications;
	•		litigation costs; and
	•		the diversion of management’s attention from managing our business.

If our computer systems fail or our facility incurs damage, our business will suffer.

     Our drug development activities depend on the security, integrity and performance of the computer systems supporting them, and the failure of our computer systems could delay our drug development efforts. We currently store most of our preclinical and clinical data at our facility. Duplicate copies of most critical data are stored off-site in a bank vault. Any significant degradation or failure of our computer systems could cause us to inaccurately calculate or lose our data. Loss of data could result in significant delays in our drug development process and any system failure could harm our business and operations.

     In addition, we store numerous clinical and stability samples at our facility that could be damaged if our facility incurred physical damage or in the event of an extended power failure. We have backup power systems in addition to backup generators to maintain power to all critical functions, but any loss of these samples could result in significant delays in our drug development process.

If, because of our use of hazardous materials, we violate any environmental controls or regulations that apply to such materials, we may incur substantial costs and expenses in our remediation efforts.

     Our research and development involves the controlled use of hazardous materials, chemicals and various radioactive compounds. We are subject to federal, state and local laws and regulations governing the use, storage, handling and disposal of these materials and some waste products. Accidental contamination or injury from these materials could occur. In the event of an accident, we could be liable for any damages that result and any liabilities could exceed our resources. Compliance with environmental laws and regulations could require us to incur substantial unexpected costs, which would materially and adversely affect our results of operations.

Risks Relating to Our Common Stock

Our stock price is likely to be highly volatile and the value of your investment could decline significantly.

     The market prices for securities of biotechnology companies in general have been highly volatile and may continue to be highly volatile in the future. Moreover, our stock price has fluctuated frequently, and these fluctuations are often not related to our financial results. For the twelve months ended December 31, 2006, the 52-week range of the market price of our stock was from $8.20 to $23.00 per share. The following factors, in addition to other risk factors described in this section, may have a significant impact on the market price of our common stock:

	•		announcements of technological innovations or new products by us or our competitors;
	•		developments or disputes concerning patents or proprietary rights;
	•		status of new or existing licensing or collaborative agreements and government contracts;
	•		we or our partners achieving or failing to achieve development milestones;
	•		publicity regarding actual or potential medical results relating to products under development by us or our competitors;
	•		publicity regarding certain public health concerns for which we are or may be developing treatments;
	•		regulatory developments in both the United States and foreign countries;
	•		public concern as to the safety of pharmaceutical products;
	•		actual or anticipated fluctuations in our operating results;
	•		changes in financial estimates or recommendations by securities analysts;
	•		changes in the structure of healthcare payment systems, including developments in price control legislation;
	•		announcements by us or our competitors of significant acquisitions, strategic partnerships, joint ventures or capital commitments;
	•		additions or departures of key personnel or members of our board of directors;
	•		sales of substantial amounts of our stock by existing stockholders, including officers or directors;
	•		economic and other external factors or other disasters or crises; and

 
•   period-to-period fluctuations in our financial results.

Because stock ownership is concentrated, you and other investors will have limited influence on stockholder decisions.

     As of December 31, 2006, our directors, executive officers and some principal stockholders and their affiliates beneficially owned approximately 31.7% of our outstanding common stock and common stock equivalents. As a result, these holders, if acting together, are able to significantly influence matters requiring stockholder approval, including the election of directors. This concentration of ownership may delay, defer or prevent a change in our control.

We have anti-takeover provisions in our corporate charter documents that may result in outcomes with which you do not agree.

     Our board of directors has the authority to issue up to 4,955,000 shares of undesignated preferred stock and to determine the rights, preferences, privileges and restrictions of those shares without further vote or action by our stockholders. The rights of the holders of any preferred stock that may be issued in the future may adversely affect the rights of the holders of common stock. The issuance of preferred stock could make it more difficult for third parties to acquire a majority of our outstanding voting stock.

     In addition, our certificate of incorporation provides for staggered terms for the members of the board of directors and supermajority approval of the removal of any member of the board of directors and prevents our stockholders from acting by written consent. Our certificate also requires supermajority approval of any amendment of these provisions. These provisions and other provisions of our by-laws and of Delaware law applicable to us could delay or make more difficult a merger, tender offer or proxy contest involving us.

     In June 2002, our board of directors adopted a stockholder rights plan and, pursuant thereto, issued preferred stock purchase rights (“Rights”) to the holders of our common stock. The Rights have certain anti-takeover effects. If triggered, the Rights would cause substantial dilution to a person or group of persons who acquires more than 15% (19.9% for William W. Featheringill, a Director who owned approximately 9.58% as of December 31, 2006, but owned more than 15% at the time the Rights were put in place) of our common stock on terms not approved by the board of directors.

We have never paid dividends on our common stock and do not anticipate doing so in the foreseeable future.

     We have never paid cash dividends on our stock. We currently intend to retain all future earnings, if any, for use in the operation of our business. Accordingly, we do not anticipate paying cash dividends on our common stock in the foreseeable future.

Information Regarding Forward-Looking Statements

     This discussion contains forward-looking statements, which are subject to risks and uncertainties. These forward-looking statements can generally be identified by the use of words such as “may,” “will,” “intends,” “plans,” “believes,” “anticipates,” “expects,” “estimates,” “predicts,” “potential,” “hope,” the negative of these words or similar expressions. Statements that describe our future plans, strategies, intentions, expectations, objectives, goals or prospects are also forward-looking statements. Discussions containing these forward-looking statements are principally contained in “Business” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations”, as well as any amendments we make to those sections in filings with the SEC. These forward-looking statements include, but are not limited to, statements about:

	•		the initiation, timing, progress and results of our preclinical and clinical trials, research and development programs;
	•		the further preclinical or clinical development and commercialization of our product candidates;
	•		the implementation of our business model, strategic plans for our business, product candidates and technology;

	•		our ability to establish and maintain collaborations with biotechnology or pharmaceutical companies and governmental agencies or other third parties;
	•		the scope of protection we are able to establish and maintain for intellectual property rights covering our product candidates and technology;
	•		our ability to operate our business without infringing the intellectual property rights of others;
	•		estimates of our expenses, future revenues, capital requirements and our needs for additional financing;
	•		the timing or likelihood of regulatory filings and approvals;
	•		our negotiations with the FDA for a special protocol assessment;
	•		our financial performance; and
	•		competitive companies, technologies and our industry.

     These statements reflect our current views with respect to future events and are based on assumptions and subject to risks and uncertainties which may cause our actual results, performance or achievements to be materially different from any future results, performances or achievements expressed or implied by the forward-looking statements. Given these uncertainties, you should not place undue reliance on these forward-looking statements. We discuss many of these risks in greater detail in “Risk Factors.” Also, these forward-looking statements represent our estimates and assumptions only as of the date of this document.

     You should read this discussion completely and with the understanding that our actual future results may be materially different from what we expect. We may not update these forward-looking statements, even though our situation may change in the future. We qualify all of our forward-looking statements by these cautionary statements.

ITEM 1B. UNRESOLVED STAFF COMMENTS

None.
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