Bayer to advance clot drug despite mixed results

By Bill Berkrot and Ransdell Pierson

NEW ORLEANS (Reuters) - An experimental blood clot preventer being developed by Bayer AG and Johnson & Johnson missed its primary efficacy goal in a mid-stage study in patients with acute coronary syndrome and led to more bleeding than a placebo, according to data released on Monday.

But the drug, rivaroxaban, did succeed in a secondary goal of showing combined risk reduction in death, heart attack and stroke compared with a placebo - giving the drugmakers enough confidence to move the medicine into large and costly late-stage trials.

The companies selected two lower doses of rivaroxaban - 2.5 milligrams or 5 milligrams given twice daily - that will be moved forward into late-stage testing among more than 13,000 patients. Selecting the doses was one of the main reasons for the study.

The primary efficacy goal was to achieve statistically significant combined risk reduction in death, heart attack, stroke and severe recurrent chest pain requiring angioplasty or bypass surgery.

J&J officials said there were not enough patients in the study to prove effectiveness, a common limitation of mid-stage studies.

"The overall results of this trial were persuasive enough that we will be conducting a 13,000-patient trial to evaluate the drug at low doses," said Dr. Michael Gibson, a Harvard cardiologist who helped lead the trial.

The companies said up to 16,000 patients may be enrolled in the new Phase III program.

The recent trial involved about 3,500 patients with acute coronary syndrome, a chronic life-threatening heart condition caused by artery blockages that can often lead to serious chest pains and heart attacks.