New clot drugs beckon as replacements for warfarin

By Ransdell Pierson

NEW YORK (Reuters) - A new crop of medicines to prevent stroke and blood clots could emerge within several years, easing dangers and hardships for patients and creating blockbuster sales for drugmakers.

The oral drugs could prove better and safer than injectable medicines such as heparin now widely used to cut the risk of dangerous blood clots in the legs and lungs after major surgery.

But makers of the new drugs say their biggest use would be as an alternative to warfarin, a pill used for decades by people with atrial fibrillation -- or irregular heartbeat -- to prevent strokes. An estimated two million Americans have been diagnosed with the heartbeat problem and the number is expected to double in the next 20 years.

Warfarin, sold by Bristol-Myers Squibb Co. under the brand name Coumadin but now widely available as a generic, is notoriously difficult to tolerate because of its interactions with food and other medicines.

Patients taking warfarin must undergo constant blood tests to ensure that warfarin levels are sufficient to prevent strokes, but not so high that they increase the risk of dangerous bleeding or brain hemorrhages. Moreover, patients scheduled for surgery must stop taking warfarin days ahead of time, to avoid serious bleeding.

"With all these disadvantages, an alternative to warfarin is direly needed, particularly since our aging population is becoming more vulnerable to atrial fibrillation and other conditions that can cause dangerous blood clots," said Dr. Stephen Winters, an associate professor of medicine at New Jersey Medical School.

"Replacement drugs for warfarin would be blockbusters because of the critical need," he said.

Among the replacement candidates, a once-daily pill called rivaroxaban, being developed jointly by Bayer AG and Johnson & Johnson, is the farthest along in clinical trials and could fetch annual sales of more than $2.5 billion, analysts say.