Washington Editor

BioCryst Pharmaceuticals Inc. stopped development of its lead drug candidate, peramivir, on poor preliminary data from a Phase III influenza study.

The news sent the company's stock (NASDAQ:BCRX) downward to close at 91 cents Tuesday, falling $1.27, or 58.3 percent.

According to the company, early data from the Phase III influenza A and B trial did not demonstrate a statistically significant difference in the primary efficacy endpoint: the length of time from the first dose to the onset of clinically significant relief of influenza symptoms, between the drug and placebo groups (p=0.17).

"Obviously, we are not happy about the results. On the other hand, given where we are with other products" - in the clinical, preclinical and discovery phases - "this allows us to really refocus our resources," Claude Bennett, BioCryst's president, chief operating officer and medical director, told BioWorld Today.

He added that conducting another Phase III flu trial would be extremely costly to BioCryst. "We did not have a partner and we would have needed one to go forward, so this may be sort of a blessing in disguise in that this clearly allows us to close the door on the flu and say Now let's go on with our newer, more exciting targets where we know we've got better control of the drug and of the clinical studies that we need to do,'" Bennett said.

BioCryst was involved in a partnership with Ortho-McNeil Pharmaceuticals Inc. and the R.W. Johnson Pharmaceutical Research Institute, both Johnson & Johnson companies, for the development of peramivir (RWJ-270201), an investigational oral influenza neuraminidase inhibitor designed to treat and prevent influenza. J&J dropped the project about a year ago, saying peramivir did not fit into its internal program. (See BioWorld Today, May 1, 2001.)

At that point, the Phase III trial was under way. J&J conducted both the Phase I and II trials.

J&J's termination of the worldwide agreement returned all rights to BioCryst, which responded by working with the FDA to complete Phase III during the 2002 winter season. (See BioWorld Today, Jan. 4, 2002.)

BioCryst added about 200 U.S. patients to those J&J had enrolled in Europe in order to complete the 1,246-patient Phase III study. "The FDA allowed us to pool all of the data, which was both good and bad, because it committed us to what was already in place," Bennett said.

The objective of the Phase III trial was to assess the efficacy and safety of peramivir in the treatment of acute influenza A and influenza B infections in otherwise-healthy adults.

In the study, peramivir was administered once a day over five consecutive days at the standard dose (800 mg per day) or loading dose (800 mg on day one followed by 400 mg per day on days 2-5). Results showed a 0.64-day and 0.53-day reduction, respectively, in the median time to improvement in influenza-infected patients vs. placebo.

Nevertheless, the company said peramivir was well tolerated in both doses studied.

"I don't know that anything went wrong in the trials," Bennett said. "We looked at the data in a lot of different ways. In some areas we had good results, but overall, we only had 0.64 days as a median difference between drug and placebo, and you've got to take the overall data; you can't sort it out bit by bit. The setback here is that we had to go through and pick up where J&J left off in the European studies, so we were committed to their protocol, their statistics and their way of doing things."

Tuesday's drop in stock value does not mark the first time BioCryst has been negatively impacted by its flu product. The company's stock dropped 53 percent to close at $7.19 in October 2000 when J&J failed to start clinical trials in the elderly due to "logistical considerations." Two months after that, the stock dropped 34 percent when J&J delayed the Phase III trial. But, BioCryst was up 17.9 percent, or 75 cents, to close at $4.95, when the company commenced U.S. enrollment of the Phase III in January. (See BioWorld Today, Oct. 13, 2000; Dec. 27, 2000; and Jan. 4, 2002.)

Now that peramivir is out of the way, BioCryst's most advanced product is BCX-1777, currently in Phase I/II studies in patients with T-cell leukemias and lymphomas. The company also has discovery programs in tissue factor/factor VIIa, hepatitis C polymerase and complement component C1s.

BioCryst on March 31 reported a net loss for the first quarter of about $1.9 million. It had about $46.7 million in cash and equivalents and 17.6 million shares outstanding.

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