But the drugmakers and industry analysts said some data in the trial were encouraging and that the medicine could still prove effective in preventing dangerous blood clots in other large trials. “Not good news, but not a death knell either,” said Michael Castor, a portfolio manager with health-care fund Sio Capital Management. He noted that the drug remains in development, including for other uses, and did show effectiveness despite missing the trial’s main goal. The stocks of both drugmakers were little changed in after-hours trading. Bristol-Myers closed unchanged at $21.98, while Pfizer fell 23 cents to $19.28, both on the New York Stock Exchange in regular trading. The Phase III trial was designed to show whether twice-daily apixaban was at least as effective as twice-daily injections of Sanofi-Aventis’ Lovenox in preventing dangerous blood clots among patients undergoing knee-replacement surgery. The failure represents another setback for two companies that had hoped apixaban would become a big seller and bolster their earnings in the face of looming generic competition within three years for their best-selling drugs. “Not to say that apixaban is buried, but this initial poor result is another in a string of poor partnering decisions that Pfizer has recently made,” said Damien Conover, an analyst with Morningstar. The drugmakers said 9 percent of knee-surgery patients receiving apixaban developed dangerous clots, versus 8.9 percent of those receiving Lovenox. The new drug, therefore, was not deemed statistically as effective as Lovenox. Bristol-Myers said this was surprising because about 16 percent of patients taking Lovenox had developed dangerous clots in earlier studies. Patients had statistically similar incidents of major bleeding, although the combined incidence of major and non-major bleeding was significantly less in patients given apixaban, the company said. Apixaban has generated excitement because it works through a new mechanism of action, by blocking a protein called Factor Xa that is instrumental in the clotting process. A similar drug, called rivaroxaban, is being co-developed by Bayer AG and Johnson & Johnson and considered slightly farther along in testing. “This would seem to benefit Johnson & Johnson and Bayer,” said Mike Krensavage, a principal of Krensavage Asset Management. “It’s another setback for Pfizer as well,” he said, referring to its string of drug failures in recent years that has driven the company’s stock to 10-year lows. Just weeks ago, Bristol-Myers described apixaban as the most promising of its medicines in late-stage studies. Analysts have said it could become a blockbuster drug, especially if it proves effective in preventing strokes among patients with atrial fibrillation, a form of irregular heartbeat. Despite the setback, the drugmakers said they remain confident in apixaban and will continue other large studies of the medicine. “This is the first of eight Phase III trials for a broad range of indications, including atrial fibrillation, and we view all of them as very significant opportunities,” said Jack Lawrence, a Bristol-Myers research official who heads the apixaban program.
Bristol, Pfizer to delay clot drug after setback.