Expert Panel Finds That Vioxx is Safe Enough — But is it, Really?

Health Canada is balking, so to speak, at the recommendation of an expert panel it appointed to consider the issue of whether Vioxx (rofecoxib) should be reintroduced on the Canadian market.  In July 2005 this expert panel advised Health Canada that Vioxx is safe enough to be marketed, again, in Canada.  Top officials at Health Canada, however, have expressed some doubt about one of the sources used by the panel in arriving at its pro-Vioxx conclusion.

Vioxx was voluntarily withdrawn from the Canadian market, and worldwide, in September 2004 after its manufacturer, Merck & Co., learned from an ongoing Vioxx study that patients taking the drug on a long-term basis faced twice the risk of suffering a heart attack or an ischemic stroke compared with patients receiving a placebo.

The Vioxx panel convened by Health Canada reportedly examined data from a wide range of sources.  One of those sources is a new meta-analysis of 138 studies on the cardiovascular risk of COX-2 inhibitors by researcher Dr. Colin Baigent, a senior scientist at the Clinical Trials Service Unit at Oxford University.  It is this particular source which has drawn some criticism from Health Canada officials, according to the August 16, 2005 edition of CMAJ.  Sally Murray reports:

Dr. Marc Berthiaume, Director of the Marketed Pharmaceuticals Division at Health Canada, is not sure about the results. "Some of the choices [Baigent] made can have skewed some of his findings: he lumped together short- and long-term findings for patients on NSAIDs." Berthiaume says Health Canada hasn’t taken an official position on the study.

According to the CMAJ piece by Sally Murray, even if the expert panel is correct that Vioxx is safe enough to return to pharmacies in Canada, Merck’s decision to withdraw Vioxx was the right thing for Merck to do given what was learned in September 2004.  "Their decision was based on the safety information available and it was a good decision," he said.  The CMAJ article quoted Merck Frosst Canada spokesperson Marlene Gauthier as agreeing: "At the time there seemed to be alternatives that had less risks."

Whether Vioxx returns to the market in Canada seemingly depends on how Health Canada ultimately views the expert panel’s recommendation.  Any reintroduction of Vioxx in Canada would begin with Merck Frosst resubmitting the drug for approval.  According to the CMAJ piece, thereafter the Health Canada approval process could take anywhere from two to eighteen months.

(Posted by: Tom Lamb)