PARK, N.C. (AP) — BioCryst
Pharmaceuticals Inc. said Thursday that it wants to extend and expand a
late-stage clinical trial of its intravenous flu drug peramivir.
Its shares fell 40 cents, or 7.8 percent, to $4.76 in midday
The company said it wants to increase the size of the trial.
It also wants to change the main goal of the trial so it can compare patients
treated with peramivir to those who have not been treated with neuraminidase
inhibitors, a group of drugs that includes peramivir and Tamiflu, among other
drugs. BioCryst said the changes would highlight peramivir’s effects and make
it more likely the drug will gain regulatory approval.
The changes would make the trial last longer, the company
said, as it would be hard to enroll enough patients by the end of 2011. That is
when enrollment of patients is currently scheduled to end. The revisions need
to be approved by the Food and Drug Administration and by the Department of Health
& Human Services, which is helping fund development of peramivir.
Peramivir is intended for patients who are hospitalized and
too sick to take an oral flu drug. It is on the market in Japan and Korea,
but is not yet approved in the U.S.
BioCryst also reported results from a late-stage safety
trial of peramivir. In the study, 230 patients were treated with peramivir
during the 2009-2010 swine flu epidemic. The patients were treated with 600
milligrams per day for five days, receiving the drug either once per day or in
two doses of 300 milligrams per day. BioCryst said the groups had similar
changes in virus levels and similar side effects.
Patients who needed more treatment after five days were
given another five days of peramivir infusions. It said 170 of the patients had
previously been treated with Tamiflu. The study included patients who were
hospitalized with confirmed or suspected flu.
BioCryst said 20 percent of the patients experienced a
serious side effect. The most common of those side effects were respiratory
failure or distress, septic shock, and kidney failure. One patient experienced
elevated levels of liver enzymes. The company said 8.7 percent of patients died
within four weeks of treatment, but no deaths were attributed to peramivir.