On November 13, 2006, the first trial studies for Merck’s Arcoxia were released to mixed reviews from American doctors and scientists. Touted to be a new and improved “Vioxx” for use in arthritis relief, Arcoxia is a cox-2 inhibitor like Vioxx, Bextra, and Celebrex. Cox-2 inhibitors are non-steroidal inflammatory drugs that directly target the cox-2 enzyme which causes inflammation and pain. These cox-2 inhibitors are generally gentler on the stomach than traditional NSAIDs but may pose more serious threats in the long-term.
Merck tested Arcoxia against diclofenac, an older NSAID proven to significantly increase the user’s risk for heart attack or stroke, during its first initial trial, also cited as the METAL study. Opponents argue that a more fair, balanced study would have resulted from comparing Arcoxia with an NSAID proven not to raise cardiovascular risks such as naproxen.
In August, Merck announced that preliminary reports concluded that Arcoxia did not pose a greater cardiovascular risk than diclofenac, but they failed to mention that more Arcoxia patients withdrew from the study due to high blood pressure. The research also noted that while rare, congestive heart failure was more common for patients receiving higher doses on Arcoxia than lower doses on diclofenac.
A similar pattern seems to be emerging around the safety of cox-2 inhibitors. Patients who need gastrointestinal relief fare better on cox-2 drugs while those at risk for heart disease should steer clear. In the end, one puts his or her own health on the line when taking newer, less studied medications. With Merck’s Vioxx and Pfizer’s Bextra and Celebrex facing the firing squad, it surprises me that drug companies are still following down this twisted, uncertain path.