Portola Pharmaceuticals Inc. stock dropped nearly 27% in active pre-market trade Thursday after phase 3 trial results missed study thresholds. The study tested two different anti-coagulation medications in preventing venous thromboembolism, or blood clots in acutely ill patients who had been hospitalized from conditions such as heart failure and stroke. The 7,513 enrolled patients were split into three groups, of which the first group's results missed the study's threshold, though the other two, larger groups met the measure, the company said. Portola also said there was no statistical difference in major bleeding between the two anticoagulation medications in the patients. The results "will be subject to discussions with regulatory agencies," Portola chief executive officer Bill Lis said, adding that the company believed in the trial's "overall robustness." About 20 million patients in G7 countries are at risk for venous thromboembolism during or after a hospital stay, the company said.
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