Study Links Actos to Bladder Cancer

Houston, TXFor patients who were relieved that Actos side effects were seemingly less severe than side effects associated with Avandia, there may still be some cause for concern. A review of data from the US Food and Drug Administration (FDA) indicates there may be a link between Actos and bladder cancer, although how strong that link is remains to be seen.

According to researchers, between 2004 and 2009, 138 reports were made to the FDA concerning bladder cancer in patients who took at least one anti-diabetic medication. Although there were 15 different diabetic medications mentioned in the 138 reports, more than one-fifth of the reports involved use of Actos, suggesting that Actos carries a higher risk of bladder cancer than other anti-diabetic medications do.

Researchers were quick to note, however, that the higher incidence of bladder cancer in Actos patients suggests that there is a possible risk but not an actual risk. Despite that, the medication guide that comes with Actos does warn of the possibility of bladder cancer. That warning was given after a study conducted by Takeda Pharmaceutical Co, maker of Actos, showed an increased risk of bladder cancer in patients who had long-term exposure to the medication and who had the highest doses.

Researchers reportedly do not know what the link between Actos and bladder cancer is or how Actos might affect the development of bladder cancer.

"In agreement with preclinical and clinical studies, AERS [Adverse Event Reporting System] analysis is consistent with an association between piglitazone [the generic name for Actos] and bladder cancer," researchers wrote. "This issue needs constant epidemiologic surveillance and urgent definition by more specific studies."

In addition to bladder cancer, a potential safety issue has been identified that could link Actos to an increased risk of rhabdomyolysis, a condition in which the patient's muscle fibers are broken down and absorbed by the bloodstream. Rhabdomyolysis can result in kidney damage. Although the situation is considered a potential safety issue, this does not mean that a causal link has been established. The FDA is reviewing data to determine if regulatory action should be taken.