Naturally, as with the introduction of any new medication class we have to carefully evaluate the efficacy and safety data of these medications. In preliminary studies, the most statistically relevant adverse events were urogenital infections, possibly related to increased glucose in the urine. The 1st in class of these medications, dapagliflozin, is currently undergoing further review by the FDA after an initial advisory panel expressed safety concerns related to an increase in bladder and breast cancers in a small and not statistically significant number of patients taking the medication versus placebo. Since then, experts have weighed in on the plausibility of linking this medication to the cancers. Firstly, the cancers appeared very early in the course of treatment (within 6 to 12 months) which alone makes a causal link unlikely. Furthermore, with respect to the bladder cancer observation, 6/9 cases had hematuria at baseline, suggesting that there may have been an underlying malignancy present already.
An interesting interpretation on these findings relates to diagnostic bias. Namely, given that these medications do cause an increase in urogenital infections, patients with this complication were the most likely to have urogenital investigations and therefore more likely to discover bladder neoplasms. In addition, given the modest weight loss attributed to this medication, breast masses might have been more easily felt. This latter phenomenon has been observed with weight-loss drugs in the past. Clearly, further study is required with respect to this issue but cautious optimism suggests that these findings are not causally linked to the medication.
Please see the attached reference for more information on this analysis.
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