Two new studies appear to confirm the link between Actos and bladder cancer, with one study indicating that the risk may be a trait of an entire family of diabetes drugs. 

In research published this week by the British Medical Journal, Canadian researchers found that Actos may double the risk of bladder cancer after two years, supporting recent warnings added to the medication about the risks associated with long-term use.

The Canadian team looked at records on more than 115,000 patients who took diabetes drugs from 1988 to 2009. They found that not only did the bladder cancer risk increase the longer a patient took Actos, but it also appeared to be dose-specific, with the risk increasing with higher doses of Actos.

In another study presented last month at the American Society of Clinical Oncology’s annual meeting, U.S. researchers suggested that the risk of bladder cancer may apply to all drugs that belong to a class of medications known as glitazones, also known as thiazolidinediones, which includes Actos, Avandia and Rezulin.

Researchers from the University of Pennsylvania looked at data from 60,000 British patients who took glitazones such as Avandia and Actos for several years. They found that after five years the patients were at a 72% increased risk of developing bladder cancer. They found that the drugs all equally increased the bladder cancer risk.

All of the drugs belonging to the class have been tied to a number of serious side effects. Actos is the only member of that class that remains one widely available in the United States, as Rezulin was recalled in 2000 due to a risk of liver damage and severe restrictions were placed on the availability of Avandia last year due to an increased risk of heart attacks.

Over the past 18 months, concerns have emerged about the risk of bladder cancer from Actos, resulting in new warning information in the United States, Europe and Canada. Several experts have suggested that an Actos recall should be issued due to the serious nature of the risk, and regulators in France removed Actos from the market in June 2011.

Actos (pioglitazone) was developed by Takeda Pharmaceuticals and approved in the United States for treatment of type 2 diabetes in July 1999. It is a once-daily pill that increases the body’s sensitivity to insulin. Related medications that also contain the same active pharmaceutical ingredient include ActoPlus Met and Duetact.

A growing number of former users of the medication are now pursuing an Actos lawsuit against Takeda after developing bladder cancer, alleging that the drug maker failed to adequately research the side effects of the medication or warn about the link between bladder cancer and Actos.

Tags: Actos, Actos Cancer, Avandia, Bladder Cancer, Cancer, Diabetes, Diabetes Drug