While not considered a serious enough risk to prevent FDA approval, earlier animal and human studies linked Actos to bladder cancer. As a condition of approval, the FDA insisted that Actos maker Takeda Pharmaceuticals look for bladder cancer in patients taking the drug.
Five years in to Takeda's 10-year study, the overall data is reassuring. Patients taking Actos do not have an increased risk of bladder cancer.
But when researchers looked only at patients who had taken Actos the longest, and who had accumulated the highest lifetime dose of the drug, they found what appears to be an increased risk of bladder cancer.
The risk emerged in patients who had taken Actos for at least 24 months.
The FDA stresses that the finding is not proof that Actos causes bladder cancer. Patients who are taking Actos are advised not to stop taking their medication unless advised to do so by their health care provider. Concerned patients should discuss the new information with their doctors.
Actos is widely considered to be safer than Avandia, the only other approved diabetes drug in its class. The FDA is currently considering whether Avandia should remain on the market. An FDA expert advisory panel recently split over the issue.