Federal health regulators have ordered Johnson & Johnson to add a new black box warning to the labels of Invokana and Invokamet regarding a risk of leg and foot amputations. A black box is the most urgent label warning employed by the U.S. Food & Drug Administration (FDA), and is reserved for the very serious or life-threatening adverse events.
According to a safety alert issued by the FDA yesterday, final results from two clinical trials indicated that leg and foot amputations occurred about twice as often in patients treated with canagliflozin (the active ingredient in Invokana and Invokamet) compared to patients treated with placebo. The most common amputations involved the toe and middle of the foot. However, leg amputations, below and above the knee, also occurred.
A number of patients also required more than one amputation. In some cases, both limbs were involved.
“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,” the FDA said. “Talk to your health care professional if you have questions or concerns. Do not stop taking your diabetes medicine without first talking to your health care professional.”
Invokana (canagliflozin) was approved by the FDA in March 2013 and was the first SGLT2 inhibitor cleared by the agency to treat Type 2 diabetes. Invokamet (canagliflozin and metformin) was approved the following year.
In December 2015, the FDA announced that the labels for all SGLT2 inhibitor drugs, including Invokana and Invokamet, would be updated to include information about diabetic ketoacidosis, a dangerous condition that can lead to diabetic coma or death when not recognized and treated appropriately. The labels for Invokana, Invokamet and several other SGLT2 inhibitors were updated yet again in June 2016, after the medications were linked to more than 100 reports of acute kidney injury.
Court documents indicate that more than 280 Invokana and Invokamet lawsuits are now pending in a federal multidistrict litigation currently underway in the U.S. District Court, District of New Jersey, all of which were filed on behalf of individuals who allegedly suffered diabetic ketoacidosis or kidney damage due to treatment with the medications. The litigation is expected to convene a series of bellwether trials beginning in September 2018. These trials will act as test cases, and could provide insight into how juries might rule in similar legal claims involving the drugs.