Quoted from http://www.reuters.com/article/2011/05/13/us-diabetes-drug-cancer-idUSTRE74C6VF20110513
More signs diabetes drug linked to bladder cancer
By Alison McCook
NEW YORK | Fri May 13, 2011 5:19pm EDT
NEW YORK (Reuters Health) - A review of official reports of bad drug reactions is revealing more signs that people taking the diabetes drug Actos are at higher risk of developing bladder cancer.
Between 2004 and 2009, more than half a million adverse reactions among people taking anti-diabetic drugs were added to an official U.S. Food and Drug Administration database. Among those reports were 138 instances of bladder cancer in patients taking at least one of more than 15 different anti-diabetic drugs.
However, more than a fifth of those bladder cancers were in patients taking Actos (pioglitazone), suggesting a "disproportionate risk" in comparison with other anti-diabetics, said study author Dr. Elisabetta Poluzzi of the University of Bologna in Italy.
A certain number of people taking a drug will always develop other problems, she explained, and it's often not clear whether those problems stem from the drug itself. As a result, these findings do not show Actos increases the risk of bladder cancer, she cautioned - just that researchers should look into it further.
"Disproportion is indicative of possible risk," Poluzzi told Reuters Health in an email, "not of an actual risk."
Still, this is not the first report to tie the drug to bladder cancer, and the possibility of increased cancer risk is already included in the prescribing information for the drug.
Last year, the FDA began a safety review of Actos after receiving early results from a long-term study by the drug's maker, Takeda Pharmaceutical Co Ltd. That study showed a raised risk of bladder cancer in patients with the longest exposure to Actos, and in those with the highest cumulative dose of the drug.