Now that Merck & Co. Inc. has pulled its Vioxx rofecoxib COX-2 inhibitor from the market for safety reasons, the big question is whether all COX-2 inhibitors will face the same problem. There are three important differences that could make some COX-2 inhibitors safer than others: the degree of selectivity for COX-2, pharmacology and half-life.
MRK (Whitehouse Station, N.J.) pulled Vioxx after an independent data safety monitoring committee for the APPROVe trial said that compared to placebo, Vioxx 25 mg doubled the risk of cardiovascular events such as myocardial infarction or stroke after 18 months of treatment. APPROVe (Adenomatous Polyp Prevention on Vioxx) was a 2,600-patient trial started in 2000 to test the ability of Vioxx to prevent recurrence of colorectal polyps in patients with a history of colorectal adenomas.
MRK said that 7.5 patients per 1000 patients (0.75%) receiving placebo had a confirmed cardiovascular event compared