FDA Advisers Review Clot Drug

WASHINGTON, September 8, 2011 -- A new anticlotting drug that had been seen as a blockbuster comes under scrutiny by a panel of outside advisers to the Food and Drug Administration Thursday, two days after a negative review by FDA staff.

Johnson & Johnson and partner Bayer Healthcare of Germany are seeking U.S. approval of Xarelto for preventing strokes in patients with a common irregular heart rhythm called atrial fibrillation.

The FDA approved the drug in July for a much smaller patient pool, patients getting knee and hip replacements, a group at heightened risk of dangerous blood clots. Even that approval followed a delay of roughly two years due to FDA concerns about internal bleeding risk.

They wrote that results of a late-stage study of more than 14,000 patients, known by the acronym ROCKET, don't make clear how safe Xarelto is, or whether it's as effective as widely used warfarin. The reviewers stated that an additional study of Xarelto, known chemically as rivaroxaban, is needed, citing questions about potential stroke and bleeding risks, among other issues.

During Thursday's daylong meeting, the FDA's Cardiovascular and Renal Drugs Advisory Committee will discuss that data, hear presentations from Johnson & Johnson officials on the drug's effectiveness and safety, ask questions and take comments from the public. The panel then is to vote on whether to recommend that Xarelto be approved for atrial fibrillation patients, and the FDA's Division of Cardiovascular and Renal Drugs is to make a final decision on approval by early November.

Several analysts on Tuesday wrote that the staff review was more negative than they had expected, increasing the risk that the approval will be delayed. When approval comes, some wrote, the label or detailed package insert could be "less generous" than what the makers are seeking, such as not allowing a claim that Xarelto works better than warfarin.

Warfarin is inexpensive and has long been a mainstay of stroke prevention. However, it's very tricky to get the dose right in each patient, so frequent blood tests are required.

Given that about 2.2 million Americans and 4.5 million people in the European Union have atrial fibrillation, multiple drugmakers have been trying to develop alternatives to warfarin.

Bayer Healthcare already markets rivaroxaban in 110 countries around the world.

Eliquis, developed by Bristol-Myers Squibb Co. and Pfizer Inc., was approved in the U.S. last month and in the 27 European Union countries on May 20.

Credit Suisse analyst Catherine Arnold wrote to investors Tuesday that she continues to expect Eliquis to dominate the category, with peak sales of $5.3 billion and two-thirds of market share by 2020.

Meanwhile, Citigroup Global Markets analyst Matthew Dodds forecasts that about 70 percent of Xarelto's U.S. sales would be for atrial fibrillation patients. Losing Xarelto for that use, or a significant delay, would hurt Johnson & Johnson but likely would only cut earnings per share by 5 cents in 2013, he wrote.