Pioglitazone is Associated With Excess Risk for Bladder Cancer

Abstract and Introduction

Abstract

Using pioglitazone for >2 years or exceeding a cumulative dose of 28,000 mg imparted the highest risk.

Introduction

In 2011, the FDA issued a safety warning for the antidiabetic drug pioglitazone (Actos). The warning states that use for longer than 1 year might be associated with excess risk for bladder cancer, based on data from a French study and an interim analysis of a manufacturer-sponsored, U.S. observational study. U.K. investigators now report on a case-control study in which they evaluated the same outcome.

Researchers identified 116,000 patients (mean age, 64) with type 2 diabetes who were new users of oral antidiabetic drugs. After a mean follow-up of 4.6 years, 470 patients had received diagnoses of bladder cancer (89 cases per 100,000 person-years). Each patient with bladder cancer was matched with as many as 20 controls. Ever use of pioglitazone was associated with 83% higher risk for bladder cancer — a significant increase — compared with never users. The bladder cancer rate increased significantly with duration of pioglitazone use, with the highest rates in patients who were exposed for >2 years, and in patients whose cumulative dose exceeded 28,000 mg. Notably, no excess risk for bladder cancer was observed for patients who received rosiglitazone (Avandia).

Journal Watch © 2012 Massachusetts Medical Society