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Why Bayer/JNJ Blood Thinner Won’t Get Superiority Claim

Nov. 15 2010 - 11:23 am | 1 views | 0 recommendations | 0 comments
By ROBERT LANGRETH
AHA2010

http://blogs.forbes.com/robertlangreth/2010/11/15/why-jnj-blood-thinner-wont-get-superiority-claim/

J&J has a press release out today touting how its blood thinner drug rivaroxaban is superior to the standard drug warfarin in preventing strokes in atrial fibrillation patients in a giant clinical trial. It and partner Bayer hope to convince the FDA to approve a marketing claim that the drug is better than warfarin.

But it is very unlikely to be able to get this claim.

Here’s why: the analysis that showed superiority excluded the large number of patients that dropped out of the trial. Such an analysis not including all patients is not viewed as the most-rigorous real world test of a drug. The J&J press release puts much less emphasis on this other analysis.

“It is totally fair to say that the trial did not demonstrate by the highest standard superiority,” said Duke University cardiologist Robert Califf, an investigator on the trial.

When all patients were analyzed, it turns out, the J&J drug was not superior to warfarin, although it clearly was at least as good. This is why a competing American Heart Association press release only stressed the noninferiority finding. Although overall bleeding rates were comparable, the J&J drug caused less fatal bleeding.

Many patients stop taking warfarin use because of the hassle of numerous doctor visits to constantly adjust the dose. It also interacts with numerous other medications and foods. The new drugs are far more convenient. In the J&J trial even the patients on rivaroxaban were getting “fake” dose adjustments of placebo warfarin. This may have led to a high dropout rate that resulted in a smaller difference between the drugs.

But another way to look at it, is that the J&J drug has a shorter half life in than warfarin. In the real world, patients often skip doses when the cannot afford a drug. This could give a small real-world advantage to warfarin in some circumstances, because it has a longer half life and missing one dose will matter less, said Boston University’s Elaine Hylek. “I am nervous about relying on a per protocol analysis” to claim a drug is superior, she said

Maja Zecevic, an editor at the Lancet medical journal, called J&J’s press release “misleading” and said that if a company submitted a paper claiming its drug was superior based on such an analysis to her journal, it would be rejected.

It may not matter to sales whether the J&J drug gets an official superiority claim. The pill is far more convenient and will eliminate a lot of the hassle making constant dose adjustments with warfarin. Duke University cardiologist Robert Califf said his own mother is now 84 and on warfarin. She is likely to go on one the J&J drug or a rival drug from Boehringer Ingelheim just because they are more convenient, he predicted. But she has good coverage that will pay for an expensive new drug, he added. Not everyone will.