Already under attack for potential heart risks, the diabetes drug Avandia is taking fresh hits from two new studies published Sept. 11 in the Journal of the American Medical Association.
One of the new studies, co-authored by drug-safety crusader Dr. Steven Nissen of the Cleveland Clinic, found that a rival drug called Actos appears to actually protect patients from heart attacks, strokes, and death. Actos, made by Japan's Takeda Pharmaceutical (4502.T), lowered the combined risk of heart attacks, stroke, and death by 18%, according to the Nissen team's latest findings. It was Nissen who published an influential study in May that first identified an increased risk of heart attack for patients taking GlaxoSmithKline's Avandia (BusinessWeek, 6/1/07).
That initial analysis came under fierce attack by Glaxo (GSK) and some physicians because it was a so-called meta-analysis, which combines the results of many disparate studies. But the second of the two new studies published in JAMA confirms Nissen's earlier findings on Avandia. While also a meta-analysis, the study by a team from Wake Forest University is seen as more rigorous, as it draws from four studies that followed more than 14,000 patients for a year or more. The Wake Forest researchers found that Avandia increased the risk of heart attack by 42%, while Nissen's earlier survey found a 43% increased risk.
GSK on the Offensive
Both Actos and Avandia are glitazones, a type of drug that lowers resistance to insulin in diabetics. Avandia, introduced in 1999, had been one of Glaxo's best-selling drugs, racking up more than $3 billion in revenue a year. But sales have slowed since the Nissen study was published in May, helping slice more than 5% off GlaxoSmithKline's stock price, and Actos has steadily gained market share.
Glaxo said in a statement Sept. 11 that the conclusions of the most recent JAMA studies "do not confirm a difference in the safety profile of Avandia (rosiglitazone) and Actos (pioglitazone)." The statement said the two studies "do not yield data robust enough to guide doctors in selecting appropriate diabetes treatments for their patients."
Nissen disagrees. "It does not make sense to give a patient Avandia when you have another drug that [lowers insulin resistance] and is safer," Nissen tells BusinessWeek, noting that heart disease is the leading cause of death for diabetics. "Why give them a drug that raises the risk?" Nissen, who was one of the first doctors to sound the alarm about heart attack risks from the Merck (MRK) painkiller Vioxx, says he thinks the Food & Drug Administration will now come under tremendous pressure to remove Avandia from the market.
The newest studies have already won over some doctors who were skeptical of Nissen's original Avandia meta-analysis. "Nissen's first article was a surprise," says Dr. Joel Zonszein, director of the clinical diabetes center at Montefiore Medical Center in New York. "I think these latest reviews now show not that the medicine is causing the heart attack, but that it is not protecting patients from it. On the other hand, Actos may actually have a beneficial effect." Zonszein predicts that most doctors will start switching their patients from Avandia to Actos. "I think even if the drug is not removed from the market, the prescription rate will drop quite a lot."