New data from the Food and Drug Administration’s (FDA) database of adverse events reinforces the black box warning on the type 2 diabetes drug canagliflozin regarding amputation risk, and further indicates that the amputation risk is not a class wide occurrence.
Canagliflozin is the active drug ingredient in the brand name medications Invokana and Invokamet, made by Johnson & Johnson’s Janssen Pharmaceuticals. The drug was the first medication approved from a class known as sodium-glucose cotransporter-2 (SGLT2) inhibitors.
In May 2017, the FDA required that a boxed warning be added to the labels of canagliflozen after so-called CANVAS studies showed a near-doubled risk of lower limb amputations in patients taking canagliflozin compared to placebo. The same risk has not been seen with other SGLT2 inhibitors such as empagliflozin (Jardiance) or dapagliflozen (Farxiga). However, the European Medicines Agency has extended the amputation warning to all SGLT2 inhibitors.
A new analysis of safety signal reports from the FDA’s adverse event reporting system (FAERS) was published recently in the Lancet Diabetes & Endocrinology by Dr. Gian Paolo Fadini and Dr. Angelo Avogaro with the University of Padova, Italy. They identified 66 reports of amputations in patients who were taking SGLT2 inhibitors. Fifty-seven – or 86 percent – of the cases involved canagliflozen. Even more concerning is that two-thirds of the reports involved patients who were not considered at high risk for amputation.
“Our data are the first to confirm the warning originated from CANVAS and tends to suggest this is not a class effect,” Dr. Fadini told Medscape Medical News.