The Food and Drug Administration said Friday that it has started a safety review of Takeda Pharmaceutical Co.’s  diabetes drug Actos looking at links to bladder cancer.

The FDA said the review was prompted from preliminary, five-year data from an ongoing study involving the drug. The study, designed to follow patients for 10-years, is being funded by Takeda.

The FDA said the results did not show an overall association between Actos and the risk of bladder cancer. But, the agency said 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.”

In a statement, the FDA said the Actos safety review is ongoing.

“The agency has not concluded that Actos increases the risk of bladder cancer,” FDA said.

Actos is in the same class of drugs as GlaxoSmithKline’s Avandia, which has been the subject of an ongoing FDA review because of concerns the drug might increase the risk of heart attacks and strokes.