Invokana Toe Amputation Risks Lead to Review by European Regulators

An ongoing clinical trial has raised concerns among European regulators about a new potential side effect of Invokana, indicating that the new-generation diabetes drug may be linked to an increased risk of toe amputations. 

The European Medicines Agency (EMA) announced a safety review of Invokana (PDF) on April 15, in response to a number of reports involving amputations among the diabetics using the drug in a clinical trial known as CANVAS, which is still ongoing.

Invokana (canagliflozin) was introduced by Johnson & Johnson and its Janssen Pharmaceuticals subsidiary in March 2013, as the first member of a new class of diabetes drugs, known as sodium-glucose co-transporter 2 (SGLT2) inhibitors. Amid aggressive marketing by the drug maker following approval, the medication was quickly adopted by the medical community, but a steady stream of potential safety risks with Invokana have emerged over the past few years, including fractures, ketoacidosis, kidney failure and new toe amputations.=.

The EMA has tasked its Pharmacovigilance Risk Assessment Committee (PRAC) to investigate the findings of the CANVAS clinical trials, following reports of cases of lower limb amputation. The EMA notes that, during the ongoing trials, there have been limb amputations linked to both patients who were given the drug and those who were given only a placebo, but a small increase in the number of amputations among Invokana test subjects has regulators concerned, although they say the increase is not statistically significant.

The PRAC will also review other members of this new class of medications, including Farxiga, Jardiance and Xigduo.

Invokana Risks

Only two years after the drug was introduced in the United States, the FDA launched an investigation into a link between Invokana and ketoacidosis in May 2015, after identifying at least 20 reports of individuals being hospitalized due to acid problems with the drug or other members of the SGLT2 inhibitor class of diabetes medications.

Following a safety review, the FDA ultimately required Johnson & Johnson to add new Invokana warnings about ketoacidosis in December 2015, urging users to stop taking the drug and seek immediate medical attention if they experience symptoms like abdominal pain, fatigue, nausea, respiratory problems or vomiting.

In September 2015, the FDA required new Invokana bone fracture warnings, indicating that the drug may also lead to decreased bone density.

A detailed review of adverse event reports submitted to the FDA during the first year Invokana was on the market, which was conducted by the Institute of Safe Medication Practices (ISMP), identified a potential risk of kidney damage with Invokana and other SGLT2 inhibitors.

These new-generation diabetes treatments work in a unique way, by impacting the normal function of the kidneys. However, investigators identified reports of kidney failure and other problems that they suspected were caused by the medication.

There are currently several hundred Invokana lawsuits pending in courts throughout the United States, which each raise similar allegations that Johnson & Johnson failed to adequately research the medication or warn consumers and the medical community about the potential risks.