The U.S. Food and Drug Administration said Friday that it has begun a safety review of the type 2 diabetes drug Actos (pioglitazone), after receiving preliminary results from a long-term study designed to gauge the risk of bladder cancer associated with use of the drug.
Early results of the study showed no overall association between Actos and the risk of bladder cancer. But, there was an increased risk of bladder cancer in patients with the longest exposure to Actos and in those with the highest cumulative dose of the drug, the FDA said.
The preliminary results are based on five years of data from an ongoing, 10-year observational study by the drug's manufacturer, Takeda Pharmaceuticals North America Inc., the FDA said.
The FDA stressed that it has not concluded that Actos increases the risk of bladder cancer.
Patients should talk to their health-care provider if they have concerns about Actos, but should not stop taking the drug unless told to do so by their health-care professional, the agency said.
Actos is a drug used to control blood sugar in patients with type 2 diabetes, and is part of a class of drugs called peroxisome proliferator-activated receptor (PPAR) agonists. The only other drug in this class is Avandia (rosiglitazone). The FDA said it has no clinical information associating Avandia with bladder cancer.
In July, an FDA advisory panel voted that Avandia should stay on the market, but with tightened controls, because of concerns that the drug may raise the risk of heart attack but not the risk of death.