"The US Food and Drug Administration (FDA) has concluded that pioglitazone, used to treat type 2 diabetes, may be linked to an increased risk of bladder cancer."
The FDA noted that there was a trend toward higher risk with increasing duration of pioglitazone, but this did not reach significance. A retrospective cohort study, however, did find a significant association. This study included 145,806 patients newly treated with antidiabetic drugs, including 10,951 "initiators" of pioglitazone. Over a mean follow-up of 4.7 years, there were 622 new cases of bladder cancer, and 54 of those were developed following pioglitazone exposure. The adjusted HR for bladder cancer after pioglitazone use compared with no use of any thiazolidinedione was 1.63 (95% CI, 1.22-2.19). Again, longer use and larger cumulative dose raised the risk, this time significantly.
This is the reason that in the first clinical trial, 3 patients used pioglitazone just for one year only. And they had good result.
"When pioglitazone was given temporarily to three chronic myeloid leukemia patients in chronic residual disease in spite of continuous treatment with imatinib, all of them achieved sustained complete molecular response, up to 4.7 years after withdrawal of pioglitazone," the authors write.
"This suggests that clinically relevant cancer eradication may become a generally attainable goal by combination therapy that erodes the cancer stem cell pool."