Studies Suggest Link Between Actos and Bladder Cancer

Boston, MAAlthough a generic version of Actos has been approved by the US Food and Drug Administration (FDA), lawsuits alleging patients were not warned about Actos side effects continue to mount. The focus is primarily on the link between Actos and bladder cancer, a link that has been supported in recent studies. There has also been concern about a link between Actos and macular edema, although the link between the two has not been as fully studied.

The link between Actos and bladder cancer is an important one because, as noted in The Canadian Medical Association Journal (7/3/12), patients with type 2 diabetes are already at a 40 percent increased risk of developing bladder cancer. If Actos further increases that risk, then patients with type 2 diabetes who take Actos could be at a substantially higher risk of bladder cancer than people who do not have type 2 diabetes.

A study published in The Canadian Medical Association Journal involved an analysis of previously conducted studies. Researchers found, "The limited evidence available supports the hypothesis that thiazolidinediones [a class of drug that includes Actos] particularly pioglitazone [the generic name for Actos] are associated with an increased risk of bladder cancer among adults with type 2 diabetes." This means that while patients with type 2 diabetes have an increased risk of bladder cancer, those patients with type 2 diabetes who also take Actos are at an even greater risk of cancer.

Just one month later, the Journal of the National Cancer Institute (8/9/12) published a different study, also suggesting a link between the use of thiazolidinediones and bladder cancer. In this case, the study examined long-term use of the drugs—including pioglitazone—and found that patients who used drugs like Actos for the longest had an increased risk of bladder cancer.

In 2011, the FDA issued a warning that use of Actos for more than one year was associated with a possible increased risk of developing bladder cancer. According to the study, conducted by Kaiser Permanente Northern California (and cited by the FDA online; 6/15/11), patients who used Actos for longer than 12 months was 40 percent higher compared with patients who were never exposed to the medication. Furthermore, a study in France found that compared with other anti-diabetic medications, pioglitazone had a significant increase in the risk of bladder cancer.

The Actos safety label was updated to reflect information about the risk of bladder cancer.