Interim safety results from an ongoing clinical trial found an increase in leg and foot amputations, mostly affecting the toes, in patients treated with the diabetes medicine canagliflozin, according to an FDA Drug Safety Communication on May 18, 2016.
The agency currently is investigating the safety issue but has yet to determine if taking canagliflozin is associated with an increased risk of leg and foot amputations. A sodium-glucose cotransporter 2 inhibitor, canagliflozin is marketed as Invokana and Invokamet by Janssen Pharmaceuticals, and was approved by the FDA in March 2013.
“Patients should not stop or change their diabetes medicines without first talking to their health care professional,” the communication states. “Doing so can lead to uncontrolled blood sugar levels that can be harmful. Over time, this can cause serious problems, including blindness, nerve and kidney damage, and heart disease. Patients taking canagliflozin should notify their health care professionals right away if they notice any new pain or tenderness, sores or ulcers, or infections in their legs or feet.”
The agency advises health care professionals to follow the recommendations in the canagliflozin drug labels and to monitor patients for the signs and symptoms described above.
Upon its approval, the FDA required five postmarketing studies for canagliflozin: a cardiovascular outcomes trial; an enhanced pharmacovigilance program to monitor for malignancies, serious cases of pancreatitis, severe hypersensitivity reactions, photosensitivity reactions, liver abnormalities, and adverse pregnancy outcomes; a bone safety study; and two pediatric studies under the Pediatric Research Equity Act (PREA), including a pharmacokinetic and pharmacodynamic study and a safety and efficacy study. In late 2015, investigators determined that the risk of bone fracture is increased with canagliflozin treatment.
Individuals who experience side effects while taking canagliflozin should submit a report through the FDA’s MedWatch program, or contact 1-800-332-1088 for more information.