June 2, 2012

Possible Link Between Actos, Bladder Cancer Found

A new study published online in the British Medical Journal (BMJ) has discovered a possible link between one popular type of diabetes drug and the risk of bladder cancer.

According to Telegraph Medical Correspondent Stephen Adams, a team of Canadian researchers, led by Dr. Laurent Azoulay of the Jewish General Hospital in Montreal, studied U.K. National Health Service (NHS) statistics and learned that individuals with Type 2 diabetes who had taken pioglitazone (Actos) had an 83% higher risk of contracting the disease.

Those who had taken it for at least two years were 88% more likely of developing bladder cancer, Adams added. Conversely, those who took rosiglitazone (Avandia), demonstrated no such increased risk, the study, which looked at the medical records of over 115,000 adults at least 40 years of age, discovered.

"In absolute terms, however, the risk remains low, the researchers found -- an extra 137 cases per 100,000 person-years," Los Angeles Times Science and Medical writer Thomas H. Maugh II said.

"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," he added. "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."

In their BMJ paper, Azoulay and colleagues reported that a total of 470 patients were diagnosed with bladder cancer after an average follow-up of 4.6 years, the Times reported. Out of those who had taken pioglitazone, there were a reported 74 cases per 100,000 person-years, while that rate increased to 88 cases for those who had taken the drug for 24 months and 137 cases for those who had consumed a lifetime amount of at least 28,000mg of the drug, the California newspaper added.

"We would reassure people that overall the risk of developing bladder cancer while taking pioglitazone is low and to stress that although taking the drug in the circumstances outlined has been associated with bladder cancer it has not been shown to cause bladder cancer," Dr Iain Frame, director of research at Diabetes UK, told Adams.

"We advise that people taking pioglitazone should continue to take it and discuss any concerns they have with their health care professionals," he added. "We would also like to highlight that the associated risk of bladder cancer only applies to people who have been taking the maximum dosage of the drug -- that is 45mg once a day for two consecutive years. Their study has shown no associated risk for people taking the lower doses of either 15mg or 30mg daily."