Merck & Co gets approvable letter for Vioxx labeling extension

Merck & Co has received an approvable letter from the US Food and DrugAdministration for an extension to the labeling of its blockbuster COX-2 inhibitor Vioxx (rofecoxib), based on the results of the previously-reported Vioxx Gastrointestinal Outcomes Research (VIGOR) study (Marketletter May 8, 2000).

Vioxx competes with Celebrex (celecoxib) from Pharmacia/Pfizer in the lucrative market to treat osteoarthritis and acute pain, and the two firms have spent millions on trials seeking to show that their products have a lower tendency to cause GI side effects than older non-steroidal anti-inflammatory drugs. Despite reservations about the robustness of their comparative data at launch, sales of the two drugs have rapidly risen to a combined total of $4.8 billion a year, with Celebrex claiming a slight majority ($2.6 billion), helped by Pfizer's marketing muscle and a slightly earlier launch onto the market.

In February, an FDA advisory panel declined to give its backing to an application by Pharmacia seeking the removal of a warning, which appears on all NSAIDs, that their use may be associated with GI ulcers and bleeding (Marketletter February 19). At the time, the panel did, however, support Merck's more modest request that Vioxx' labeling could be changed to show that it causes fewer GI side effects than the NSAID naproxen in patients with rheumatoid arthritis, an indication for which it is not yet approved in the USA.