Patients who take the diabetes drug Actos (pioglitazone) two years or longer are twice as likely to develop bladder cancer than those who haven’t taken the drug, Canadian researchers have found.
The Canadian study, led by Montreal epidemiologist Dr. Laurent Azoulay and published online in the British Medical Journal, analyzed the medical records of nearly 116,000 patients in Great Britain newly treated with diabetes drugs between 1988 and 2009. The records were consolidated in Great Britain’s General Practice Database from about 600 general practices in that country.
The researchers found that while absolute risk of developing bladder cancer was relatively small, patients taking Actos for two years or longer and in higher doses had an 83 percent increased risk of bladder cancer compared to those who had not taken Actos.
Overall, 470 patients were diagnosed with bladder cancer during about four and half years of follow-up. The study found no increased risk of bladder cancer in patients using Avandia (rosiglitazone), another diabetes drug in the same class as Actos.
Made by Japan’s Takeda Pharmaceutical Co., Actos quickly became one of the top-selling drugs in the U.S. after the Food and Drug Administration approved it as a treatment for type 2 diabetes in July 1999. Last June, however, after reviewing results of an ongoing epidemiological study, the agency warned that patients taking Actos for one year or longer were exposed to a risk of bladder cancer 40 percent higher than those who hadn’t taken the drug. The FDA ordered Takeda to include the increased bladder cancer risk on the product’s labeling.
In an editorial published with the new study, Dominique Hillaire-Buys and Jean-Luc Faillie from the Regional Universitaire de Montpellier in Montpellier, France indicated the new study would cast further doubt on the safety of Actos over other diabetes medications. They concluded that “prescribers who are ultimately responsible for therapeutic choices can legitimately question whether the benefit-risk ratio of pioglitazone is still acceptable for their patients.”