Invokana May Increase Risk of Lower Limb Amputations. Regulators in the United Kingdom are warning that Invokana (canagliflozin), a type 2 diabetes medication manufactured by Johnson & Johnson subsidiary Janssen, may carry an increased risk of lower limb amputations. Similar warnings were recently issued by the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA).
Parker Waichman LLP has decades of experience representing clients in product liability and personal injury litigation. The firm continues to offer free legal consultations to individuals with questions about filing an Invokana lawsuit.
Invokana is part of a class of drugs known as sodium-glucose co-transporter 2 (SGLT2) inhibitors. These medications lower blood sugar, in combination with diet and exercise, by causing more glucose to be released in the urine.
On Mar. 22, 2017, the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) warned that Invokana may be associated with an increased risk of lower limb amputation. The updated prescribing information describes amputations as an uncommon side effect, occurring in fewer than 10 patients per 1,000.
The UK regulators advise healthcare professionals to monitor Invokana patients at risk for amputation. These includes individuals with poor control of diabetes and cardiovascular problems. If patients develop foot problems such as skin infection, ulcers, osteomyelitis or gangrene, healthcare professionals should consider stopping the medication.
The MHRA announcement comes after a similar warning from the EMA, who said the increased risk may affect Invokana and other SGLT2 inhibitors. The possible increased rates of amputation mostly affect the toes, the regulatory agency said.
In a statement released in February, the EMA advised “Patients taking these medicines are reminded to check their feet regularly and follow their doctor’s advice on routine preventative foot care. They should also tell their doctor if they notice any wounds or discoloration, or if their feet are tender or painful,”
SGLT2 inhibitors include drugs such as: AstraZeneca’s Ebymect (dapagliflozin /metformin), Edistride (dapagliflozin), Xigduo (dapagliflozin/metformin) and Forxiga (dapagliflozin), Janssen Pharmaceuticals’ Invokana (canagliflozin) and Vokanamet (canagliflozin /metformin), Eli Lilly and Boehringer Ingelheim’s Jardiance (empagliflozin) and Boehringer’s Synjardy (empagliflozin /metformin).
“An increase in lower limb amputations has not been seen in studies with other medicines in the same class, dapagliflozin and empagliflozin. However, data available to date are limited and the risk may also apply to these other medicines,” EMA stated.
“The incidences of lower limb amputation given above for both CANVAS and CANVAS-R are based on interim data, and final incidence rates will depend on analysis of the final study datasets,”
FDA Places Boxed Warning on Invokana, Invokamet for Leg and Foot Amputations
The FDA has also updated the label on Invokana and Invokamet warning about the risk of leg and foot amputations. The diabetes drugs will have a new boxed earning, the most serious type of warning, disclosing this information. Regulators announced the label update on May 16, 2017. The FDA, EMA and MHRA announced these updates following data from two large clinical trials: CANVAS (Canagliflozin Cardiovascular Assessment Study) and CANVAS-R (A Study of the Effects of Canagliflozin on Renal Endpoints in Adult Participants with Type 2 Diabetes Mellitus).
Participants in the trial were twice as likely to suffer from leg and foot amputations when taking Invokana compared to those taking a placebo.
Regulators said data showed that canagliflozin users were twice as likely to suffer from leg and foot amputations compared to those taking a placebo. In the CANVAS trial, the risk of amputation over a year period was equivalent to 5.9 out of every 1,000 patients taking canagliflozin. Comparatively, the risk was 2.8 out of every 1,000 patients taking a placebo.
Amputations mostly affected the toe and the middle of the foot, the FDA said. In some cases, however, the leg was amputated. Leg amputations occurred both above and below the knee. Some patients had more than one amputation. The agency said patients often experienced lower limb infections, gangrene, diabetic foot ulcers and ischemia prior to amputation. Patients were more likely to undergo amputations if they had amputations previously.
Data from the CANVAS-R trial also documented a higher risk of lower limb amputations among canagliflozin users compared to those taking a placebo. Over a year period, the risk of amputation with canagliflozin was 7.5 out of every 1,000 patients compared to 4.2 out of every 1,000 taking a placebo. Nearly 6,000 patients were treated with canagliflozin in both trials. The study was limited to patients with cardiovascular disease or cardiovascular risk factors other than type 2 diabetes. The boxed warning, however, is addressed to all Invokana and Invokamet users regardless of cardiovascular risk.
Patients should speak to their healthcare professional immediately if they develop the following symptoms:
- New pain or tenderness
- Sores or ulcers
- Infections of the legs or feet
Patients should not stop taking their diabetes medication without first speaking to their healthcare professional.
The agency advised doctors to consider whether patients have an increased risk of amputations prior to prescribing Invokana or Invokamet. Risk factors include a prior amputation, peripheral vascular disease, neuropathy and diabetic foot ulcers. Canagliflozin treatment should be discontinued if patients develop these symptoms, the FDA says.
Last May, the FDA announced that interim data suggested an increased risk of leg and foot amputations, mostly affecting the toes among Invokana and Invokamet users. Regulators said they were investigating the issue. The boxed warning is an update on this previous communication.
Regulators state that Invokana is associated with other adverse events, including low blood pressure, ketoacidosis, kidney problems, high blood potassium, serious urinary tract infections, low blood sugar when taken with other diabetes drugs, bone breaks and increased cholesterol.
Parker Waichman notes that Invokana lawsuits are currently being filed over ketoacidosis, a condition where the blood becomes too acidic.
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