Biocryst Pharmaceuticals Initiates Intravenous Peramivir Phase I Clinical Trial

BIRMINGHAM, Ala., March 9 /PRNewswire-FirstCall/ -- BioCryst Pharmaceuticals, Inc. today announced that it has initiated a Phase I clinical trial of peramivir, the company's lead influenza neuraminidase inhibitor, to determine the pharmacokinetics and safety of single and multiple doses of an intravenous (IV) formulation of the drug in healthy volunteers. This double-blind, randomized, dose-escalating study of peramivir is being conducted in association with the National Institute of Allergy and Infectious Diseases (NIAID), at the National Institutes of Health (NIH). The trial is being conducted at the NIH Clinical Center in Bethesda, MD, under the direction of John Beigel, M.D., of the Department of Critical Care Medicine at the NIH.

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Part of a new class of antiviral agents, peramivir works by inhibiting viral neuraminidase, an enzyme essential for the influenza virus to spread and infect its hosts. The drug was designed to treat and prevent various types of flu and in laboratory tests has been shown to be a potent and selective inhibitor of influenza A and B neuraminidases. Additionally, in pre-clinical studies, peramivir has shown encouraging activity against H5N1 avian influenza, leading researchers to believe that in the proper formulation, the drug may be effective against that virus, as well as against other life- threatening influenza strains that infect humans.

This open-label study is scheduled to enroll approximately 70 volunteers and consists of two parts, a Single-Dose Safety and Tolerability Study and a Multi-Dose Safety and Tolerability Study. In the initial Single-Dose Study, volunteers will receive either a placebo or a single dose infusion of peramivir ranging from 0.5 mg/kg to 5.0 mg/kg. In the Multi-Dose Safety and Tolerability Study, patients will receive one daily dose of either peramivir or placebo for five consecutive days. The Multi-Dose Study will use two of the doses selected from the Single-Dose Study.

"We are pleased and honored to be collaborating with Dr. Beigel, who is a leading authority on influenza, especially the H5N1 avian influenza virus," said Dr. Charles E. Bugg, Chairman and CEO of BioCryst. "These Phase I studies are a precursor to further clinical studies we, in collaboration with Dr. Beigel and his colleagues, have planned for later this year. Those studies will examine peramivir in the treatment of influenza infected patients in Southeast Asia."

The influenza virus is a member of the orthomyxovirus family and causes an acute viral disease of the respiratory tract. Unlike the common cold and some other respiratory infections, seasonal flu can cause severe illness, resulting in life-threatening complications. According to the Centers for Disease Control and Prevention, every year in the United States more than 200,000 people are hospitalized from flu complications, and about 36,000 people die from flu. Most at risk are young children, the elderly and people with seriously compromised immune systems.

H5N1 avian influenza is caused by a subtype of the influenza A virus. Circulating among birds worldwide, the virus is considered extremely contagious in birds. It is believed that all species of birds are susceptible to avian influenza, but domestic poultry, including chickens and turkeys, are among the most susceptible to the highly pathogenic strain. At least 175 people have contracted H5N1 avian influenza, of which 96 have died. Almost all of these infections have resulted from contact with infected poultry.

About BioCryst

BioCryst Pharmaceuticals, Inc. 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.

BioCryst's lead product candidate, Fodosine(TM), is a transition-state analog inhibitor of the target enzyme purine nucleoside phosphorylase (PNP). The drug is currently in a Phase IIa trial for patients with T-cell leukemia and a combination IV and oral Phase I pharmacokinetic trial in healthy volunteers was recently completed. Results of the Phase IIa and the Phase I pharmacokinetic trial will assist in the design of a planned combination IV and oral Phase IIb pivotal clinical trial in patients with T-cell leukemia. The Company is negotiating a Special Protocol Assessment with the FDA for this planned trial. Additionally, Fodosine(TM) is currently being studied in a Phase I trial with an oral formulation in cutaneous T-cell lymphoma (CTCL), a Phase II trial in chronic lymphocytic leukemia (CLL) and a Phase I/II trial in B-cell acute lymphoblastic leukemia (B-ALL). Fodosine(TM) has been granted Orphan Drug status by the U.S. Food and Drug Administration for three indications: T-cell non-Hodgkin's lymphoma, including CTCL; 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 (ALL). Additionally the FDA has granted "fast track" status to the development of Fodosine(TM) for the treatment of relapsed or refractory T-cell leukemia. In February, 2006 BioCryst announced it had entered into an exclusive licensing agreement with Mundipharma International Holdings Limited to develop and commercialize Fodosine(TM) in markets across Europe, Asia and Australasia for use in oncology.

In August, 2005, BioCryst initiated a Phase Ib study with its second- generation PNP inhibitor, BCX-4208, to evaluate the safety, tolerability and pharmacokinetics of multiple oral doses of BCX-4208. In November, 2005 BioCryst announced it had entered into an exclusive licensing agreement with Roche to develop and commercialize BCX-4208 for the prevention of acute rejection in transplantation and for the treatment of autoimmune diseases.

Additionally, BioCryst has re-initiated clinical development of peramivir, an inhibitor of influenza neuraminidase, with a focus on intravenous and intramuscular delivery. Also, BioCryst has identified a clinical candidate, BCX-4678, in its hepatitis C polymerase inhibitor program, and is advancing that compound through preclinical testing with the goal of filing an IND in 2006. For more information about BioCryst, please visit the company's web site at http://www.biocryst.com.

Forward-looking statements

These statements involve known and unknown risks, uncertainties and other factors 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. These statements reflect our current views with respect to future events and are based on assumptions and subject to risks and uncertainties. Given these uncertainties, you should not place undue reliance on these forward-looking statements. Some of the factors that could affect the forward-looking statements contained herein include that we or our licensees may not be able to enroll the required number of subjects in clinical trials of Fodosine(TM), BCX-4208 or peramivir that each of the Phase IIa trial for patients with T-cell leukemia, Phase I trial of BCX-4208, the Phase I trial with peramivir, the Phase I trial of Fodosine(TM) for treatment of patients with cutaneous T-cell lymphoma, the Phase I/II trial of Fodosine(TM) for treatment of patients with B-cell ALL and the Phase II trial of Fodosine(TM) for advanced fludarabine-refractory CLL may not be successfully completed, that BioCryst or its licensees may not commence as expected additional trials with Fodosine(TM) and with BCX-4208 or planned human trials with peramivir or BCX-4678, that Fodosine(TM), BCX-4208, peramivir, BCX-4678 or any of our other product candidates may not receive required regulatory clearances from the FDA, that clinical trials of Fodosine(TM) may not show the drug is effective over the initial treatment period, that ongoing and future clinical trials may not have positive results, that we may not be able to obtain a Special Protocol Assessment or otherwise be able to complete successfully the Phase IIb trial that is currently planned to be pivotal, that we or our licensees may not be able to continue future development of Fodosine(TM), BCX-4208, peramivir, BCX-4678 or any of our other current development programs including tissue factor/factor VIIa, that Fodosine(TM), BCX-4208, peramivir, BCX-4678 or our other development programs may never result in future product, license or royalty payments being received by BioCryst, that BioCryst may not reach favorable agreements with potential pharmaceutical and biotech partners for further development of its product candidates, that BioCryst may not have sufficient cash to continue funding the development, manufacturing, marketing or distribution of its products and that additional funding, if necessary, may not be available at all or on terms acceptable to BioCryst. Please refer to the documents BioCryst files periodically with the Securities and Exchange Commission, specifically BioCryst's most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, current reports on Form 8-K which identify important factors that could cause the actual results to differ materially from those contained in the projections or forward-looking statements.

Contact: BioCryst Pharmaceuticals, Inc. Jonathan M. Nugent V.P. Corporate Communications (205) 444-4633

CONTACT: Jonathan M. Nugent, V.P. Corporate Communications of BioCrystPharmaceuticals, Inc., +1-205-444-4633

Web site: http://www.biocryst.com/