Taking the diabetes drug pioglitazone, better known by the brand name Actos, doubles the risk of developing bladder cancer, Canadian researchers have found. In absolute terms, however, the risk remains low, the researchers found -- an extra 137 cases per 100,000 person-years. According to the National Cancer Institute, there are an estimated 70,530 cases of bladder cancer in the U.S. each year and 14,680 deaths.
The U.S. Food and Drug Administration warned in June 2011 that taking Actos for at least a year increased the risk of bladder cancer by at least 40%, and ordered the drug's manufacturer, Takeda Pharmaceutical North America, to note the risk on the drug's label.
Actos and its sister drug, rosiglitazone or Avandia, are members of a family of drugs known as thiazolidinediones, which have proved very effective at reducing resistance to insulin in patients with Type 2 diabetes. But concerns about the drugs have grown because they have been shown to increase the risk of cardiovascular disease. The new findings add to concerns.
A team headed by Dr. Laurent Azoulay, an epidemiologist at Jewish General Hospital in Montreal, examined data from the General Practice Database, which contains patient records from more than 600 general practices in the United Kingdom. The team studied 115,727 patients newly treated with diabetes drugs and matched each bladder cancer case to 20 healthy controls.