Shared from Law360, New York (May 16, 2017, 6:29 PM EDT) -- The U.S. Food and Drug Administration on Tuesday said it has confirmed that Janssen Pharmaceuticals' diabetes medications Invokana and Invokamet can increase the risk of patients needing to have their legs or feet amputated and said the drugs will now require black-box warnings.
The agency had first sent out an alert a year ago that patients in clinical trials for the drugs were twice as likely to need amputations as those on a placebo, and the FDA on Tuesday issued the final results from two clinical trials. Canagliflozin, which the Johnson & Johnson unit sells as Invokana, Invokamet and Invokamet XR, is used to treat Type 2 diabetes.
According to the first clinical trial, known as CANVAS, 5.9 out of 1,000 patients on the drug needed an amputation over a year, while the placebo's numbers were 2.8 out of 1,000 patients. The second trial CANVAS-R, showed 7.5 out of 1,000 patients needed an amputation when on the drug compared to 4.2 on the placebo.
Most of the amputations involved the foot or a toe, with some others involving legs, the FDA said, adding that some patients needed more than one amputation.
“Patients taking Canagliflozin should notify your health care professionals right away if you develop new pain or tenderness, sores or ulcers, or infections in your legs or feet. Talk to your health care professional if you have questions or concerns,” the agency said in a safety communication. “Do not stop taking your diabetes medicine without first talking to your health care professional.”
Janssen said Tuesday that patients who had amputations before starting the drug were most likely to need another one.
“At Janssen, patient safety is our highest priority,” spokesman William Foster said in an statement. “We are working with FDA to include this information in the prescribing information for Canagliflozin and look forward to the presentation of the full CANVAS Program results at the American Diabetes Association Scientific Sessions in June.
Invokana was the first in a class of drugs known as sodium-glucose cotransporter 2, or SGLT2, inhibitors. It was approved amid concerns about cardiovascular health and bone safety, and the FDA has since updated Invokana's and Invokamet's warning labels to reflect risks of bone fractures. The drugs' labels — as well as the labels of other SGLT2 inhibitors — have also been revised to disclose risks of a blood disorder and urinary tract infections.
--Additional reporting by Jeff Overley. Editing by Orlando Lorenzo