STUDY DATA ON VIOXX SUCCESSOR SHOWS GOOD AND BAD

Preliminary study data on Merck's experimental painkiller Arcoxia show it presents thrombotic cardiovascular risks similar to a commonly-used anti-inflammatory drug, but other findings suggest that more work needs to be done before Arcoxia is finally approved for the U.S. market.

The FDA deemed Arcoxia "approvable" in October 2004, but said Merck would have to provide additional safety data before the drug could receive final approval. Arcoxia (etoricoxib) is intended to treat arthritis and pain. The drug is a COX-2 inhibitor like its blockbuster predecessor Vioxx (rofecoxib), which Merck pulled off the market nearly two years ago after studies found the drug increased the risk of heart attack and stroke. Vioxx had global sales of $2.5 billion in 2003.

Merck released data Aug. 23 from its Multinational Etoricoxib and Diclofenac Arthritis Long-Term, or MEDAL, Program -- three studies involving 60-mg or 90-mg Arcoxia in more than 34,000 osteoarthritis and rheumatoid arthritis patients -- which showed the "relative risk" of confirmed thrombotic cardiovascular events was similar to diclofenac. But the incidence of patients withdrawing from the trial because of side effects related to congestive heart failure and edema (fluid retention) was "significantly higher" for 90-mg Arcoxia than for diclofenac, while withdrawal because of high blood pressure-related adverse effects was significantly higher for both 60- and 90-mg Arcoxia than for diclofenac. However, study patients were much more likely to quit taking diclofenac because of gastrointestinal and liver-related side effects.