Bladder cancer risks aren’t likely to send the diabetes drug pioglitazone (Actos) down the same path as rosiglitazone (Avandia), according to an exclusive InFocus report from the American Diabetes Association meeting.
Earlier this month French and German regulators halted sales of pioglitazone over excess bladder cancer seen in a French epidemiologic study, which the FDA followed with a warning pending further review of the data.
Yet the situation may not be as dire as the cardiovascular risks that led the European Medicines Agency to take rosiglitazone off the market last year and the FDA to severely restrict access to it, as leading diabetes specialist John Buse, MD, PhD, explains in an interview with MedPage Today Senior Staff Writer Crystal Phend.
“I don’t think it [pioglitazone] will be taken off the market in the United States,” says Buse, director of the Diabetes Care Center at the University of North Carolina at Chapel Hill and a past president of the ADA.
The same kinds of studies that suggested an increase in bladder cancer showed a decrease in other more common types of cancers, he notes.
Pioglitazone also holds some unique benefits among anti-diabetic treatments that may argue for a clinical need to keep the drug on the market, Buse adds.
In June when the FDA issued a warning about Actos being linked with bladder cancer, Sue Kirkman, MD, vice president of medical affairs for the American Diabetes Association, said just prior to the decision that the evidence of bladder cancer risk with pioglitazone has been “conflicting, and it’s hard to know whether this is a real problem or not.”
She said her organization’s main concern is that patients might stop taking their medication after hearing the news about the increased risk rather than talking to their doctors first.
That worry is shared by The Endocrine Society and the American Association of Clinical Endocrinologists. In a joint statement with the American Diabetes Association, the organizations emphasized that patients currently taking pioglitazone should remain on the drug unless otherwise advised by a doctor.
“Stopping diabetes medications can result in higher levels of blood glucose that may cause serious short-term health problems and could increase the risk of diabetes-related complications in the long term,” the organizations said.
Kirkman noted, though, that some of the clinicians her organization represents have made the decision not to use the class, or have at least given it serious consideration before prescribing.
“We already knew there were other issues with the class, aside from those seen with rosiglitazone,” she said. “There are concerns about fractures, fluid retention, and congestive heart failure.”
But not all clinicians were quick to decry use of pioglitazone or the TZD class. Joel Zonszein, MD, of Albert Einstein College of Medicine in New York City, called the earlier European decision “precipitous and premature” because it was based on a retrospective study and found only a minor increase in cancer risk.
“During the last three decades, studies have shown that treating diabetes early and aggressively results in much better outcomes,” Zonszein said. “There is a need for medications such as Actos that can slow down the devastating results of the diabetes epidemic.”
The FDA began its review of pioglitazone and the potential risk of bladder cancer last September and said it will continue to monitor data until the full 10-year study is complete.