October 6th, 2011

Rivaroxaban Roundup: ATLAS-ACS an AHA Late-Breaker, NEJM Perspective, NYT Overview

Rivaroxaban (Xarelto, Bayer and Johnson & Johnson) is in the news today.

In a rare move, the AHA has added the ATLAS ACS 2-TIMI 51 trial to its roster of Late-Breaking Clinical Trials to be presented next month at the AHA’s Scientific Sessions in Orlando. C. Michael Gibson will present the results on Sunday, November 13, at 5:13 PM.

Last week, Bayer announced the top-line results of the trial, and said that rivaroxaban had met the study’s primary endpoint, “showing a statistically significant reduction in the rate of events for the primary composite endpoint of cardiovascular death, myocardial infarction and stroke in patients with ACS, compared to standard therapy plus placebo.” However, the company also announced a significant increase in major bleeding events associated with rivaroxaban.

In a perspective about the FDA’s advisory panel on rivaroxaban published in the New England Journal of Medicine, Thomas Fleming (a member of the advisory panel) and Scott Emerson review some of the controversial aspects of the ROCKET AF trial discussed by the panel, which ultimately voted to recommend approval of the drug for stroke prevention in AF. They note that although rivaroxaban was superior to warfarin in the overall trial, the time in the therapeutic range (TTR) for patients taking warfarin was only 55%, which was low compared with other trials. In centers where the TTR was 67% or higher, by contrast, there was little difference between the two drugs in the main outcome.

Another problem with ROCKET was that the on-treatment analysis didn’t include events that occurred more than  2 days following discontinuation of the drug. This is potentially significant, write the authors, since the half-life of rivaroxaban is substantially shorter than that of warfarin (5-9 hours vs. 40 hours). When events that occurred between days 2 and 7 after drug discontinuation are included in the analysis, rivaroxaban is no longer superior to warfarin.

Fleming and Emerson also discuss the recent arrival of dabigatran, which is now approved for stroke prevention in AF and which demonstrated superiority to warfarin in the RE-LY trial. They express concern “that rivaroxaban could be inferior to either dabigatran or warfarin, particularly when the latter is ‘used skillfully.'” Approval of rivaroxaban, they write, “could lead to an unproven treatment displacing an effective treatment on the basis of overzealous promotion of more convenient once-daily dosing.”

Finally, rivaroxaban is included in an upbeat roundup of the new generation of anticoagulants in the New York Times. Cardiologists Christopher Granger and Jessica Mega are quoted extensively, generally praising the new drugs. The one downside to the new drugs is cost, according to the story. But the appearance of several new drugs may create a “downward pressure on costs,” writes Paula Span. Granger offers additional hope: “We may be able to persuade pharmaceutical companies that it’s better to have broader use at lower prices than less use at higher prices.”

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