The withdrawal of the arthritis drug Vioxx from the market continues to have ripple effects.
Two similar medications will soon become the focus of studies on whether they -- like Vioxx -- raise the risk of heart attack and stroke with long-term use. And the future of a highly anticipated "second generation" version of these drugs, known as Cox-2 inhibitors, now appears in doubt.
Researchers are making a strong case for this experimental drug, called Arcoxia, saying that it appears to work as well as other Cox-2 inhibitors. In defending the drug, they cite a study presented last month at the American College of Rheumatology's annual meeting.
In that study, Arcoxia didn't appear to raise the risk of cardiovascular events, although the research followed participants only for an average of nine months.
The study, designed to see how the drug affected the gastrointestinal tract, included 7,111 patients with osteoarthritis who took either Arcoxia or an older medication, diclofenac, which is a traditional nonsteroidal anti-inflammatory drug.
Traditional NSAIDs, such as ibuprofen and acetaminophen, increase the risk of ulcers and gastrointestinal bleeding with long-term use. Cox-2 drugs, which are known as selective NSAIDs, were designed to limit stomach side effects. Arcoxia was developed with the goal of providing even better pain control while keeping stomach side effects at a minimum.
In the new study, fewer people taking Arcoxia dropped out of the trial due to stomach problems compared with people taking diclofenac. Arcoxia may also be better at relieving pain than the first generation of Cox-2 drugs, said Dr. Herbert Baraf, the lead investigator of the trial and director of the Center for Rheumatology and Bone Research in Wheaton, Md.
"I don't see any difference in gastrointestinal issues between this drug and any of the Cox-2 drugs, but there does appear to be an efficacy difference, in particular with patients with ankylosing spondylitis and rheumatoid arthritis," he said.
Manufacturer Merck & Co. is seeking approval of Arcoxia for treating osteoarthritis, rheumatoid arthritis, chronic low back pain, acute pain, menstrual pain, acute gouty arthritis and ankylosing spondylitis.
But the effect of Cox-2s on cardiovascular disease has taken the spotlight away from the drugs' ability to minimize pain and reduce the risk of stomach problems. And that means Arcoxia's safety is far from settled. Besides following patients for only about nine months, the study was not designed to look for heart attacks and strokes.
