Preliminary Evidence Links Diabetes Drug Actos to Bladder Cancer
The US Food and Drug Administration (FDA) has announced that it will investigate preliminary epidemiological evidence that suggests a link between the diabetic medication Actos (generic name pioglitazone, Takeda Pharmaceuticals) and an increased risk of bladder cancer. The announcement, used September 17, stresses that at the moment, there is no clear evidence that Actos increases risk and patients should not stop taking the drug unless told to do so by their health care professional.
FDA Review is Ongoing; No Conclusions Have Been Reached
Pioglitazone was approved in 1999 to improve glycemic control in adults with Type 2 Diabetes Mellitus. The drug, which is in a class of medications known as thiazolidinediones (TZD), works by reducing insulin resistance. A similar medication is Avandia, marketed by GlaxoSmithKline.
The basis for the safety review is the mid-term (5 year) results of an ongoing 10-year observational cohort study among 193,000 patients with diabetes who are members of the Kaiser Permanente Northern California health plan. Data collected between January 1, 1997 and April 20, 2008 did not show a statistically significant association between exposure to Actos and an increased risk of bladder cancer, but the risk did appear to increase as patients who used the drug long-term.
Patients taking pioglitazone for at least 2 years experienced a higher rate of bladder cancer than those taking other agents. The label for Actos already contains information about bladder cancer risk in the “Precautions - Carcinogenesis, Mutagenesis, Impairment of Fertility” section.
What may complicate the findings is that diabetic patients may already have an increased risk of several cancers, including bladder cancer. The most important modifiable risk factor in the development of bladder cancer is smoking.
Patients who have experienced adverse effects due to Actos (pioglitazone) should contact MedWatch, the FDA’s safety information and adverse event reporting system online at www.fda.gov/medwatch or by mail at MedWatch, FDA, 5600 Fishers Lane, Rockville, Maryland 20852-9787. A telephone number is also available: 1-800-FDA-1088.
The full safety announcement from the FDA can be found here.
• Ongoing Safety Review of Actos (pioglitazone) and Increased Risk of Bladder Cancer