September 19, 2010 — The US Food and Drug Administration (FDA) has launched a safety review of pioglitazone (Actos; Takeda Pharmaceuticals), citing preliminary epidemiologic evidence suggesting that the diabetes medication may be linked to a higher risk for bladder cancer, the agency said on September 17.
As with other announcements about drugs under postmarket scrutiny, the agency noted that it has not yet concluded that pioglitazone increases the risk for bladder cancer and urged patients taking the medication to continue to do so unless told otherwise by their healthcare professional.
Pioglitazone was approved in 1999 as an adjunct to exercise and diet to improve glycemic control in adults with type 2 diabetes mellitus, primarily by reducing insulin resistance. It is 1 of 2 FDA-approved medications in the thiazolidinedione class, along with rosiglitazone (Avandia; GlaxoSmithKline), which is itself the subject of an ongoing safety review. The agency is still deliberating whether to take rosiglitazone off the market or add restrictions and label warnings about its cardiovascular risks, following a mixed vote by a joint-FDA advisory panel meeting in July. Pioglitazone generally has been viewed as a safer option for patients who warrant treatment with a thiazolidinedione-class drug: During the rosiglitazone advisory hearing, most panel members said they believed pioglitazone to be safer than rosiglitazone. The cancer signal with pioglitazone, however, was discussed during the rosiglitazone meeting and clearly caused consternation among some of the panel members.
According to an FDA statement, its announcement Friday about pioglitazone is based on an ongoing 10-year observational cohort study, as well as a nested, case-control study of the long-term risk for bladder cancer in roughly 193,000 patients with diabetes who are members of the Kaiser Permanente Northern California health plan. An interim analysis of data collected from January 1, 1997, through April 20, 2008, did not show a statistically significant association between any exposure to pioglitazone and an increased risk for bladder cancer. However, this risk did increase in patients exposed to the highest cumulative dose, and those with the longest exposure, reaching statistical significance after 2 years.
The first suggestion of a possible cancer risk emerged in preclinical carcinogenicity studies described in the drug's FDA-approved label. Bladder tumors were seen in male rats receiving a dose of pioglitazone that produced blood drug levels equivalent to what a clinical dose would generate. And in 2 clinical studies, patients receiving pioglitazone experienced a higher rate of bladder cancer than patients taking other agents.
More information about today's FDA announcement is available on the agency's Web site.
To report adverse events related to pioglitazone, contact MedWatch, the FDA's safety information and adverse event reporting program, by telephone at 1-800-FDA-1088, by fax at 1-800-FDA-0178, online at https://www.fda.gov/medwatch, or by mail to MedWatch, FDA, 5600 Fishers Lane, Rockville, Maryland 20852-9787.
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Cite this: FDA Studying Possible Link Between Pioglitazone and Bladder Cancer - Medscape - Sep 19, 2010.