Invokana, a relatively new drug used to treat Type 2 diabetes has recently come under fire for a number of potential risks associated with the drug. While much of the bad press regarding Invokana has to do with ketoacidosis, a potentially life-threatening condition, there are other issues associated with Invokana. There is also evidence that manufacturers Johnson & Johnson and Janssen, as well as the FDA, were aware of these issues, in particular the risk of heart attack and stroke linked to Invokana, yet failed to warn consumers.
Doctors Disagree with Janssen’s Claim That Invokana is Safe
In January, 2013, representatives from Janssen Pharmaceuticals presented information to the FDA on the increase of Type 2 diabetes in the United States and the benefits associated with their new drug, Invokana. During the question and answer session, Dr. Sidney Wolfe raised some questions about the safety of Invokana. The most pressing concern voiced by Wolfe was blood clots which could lead to heart attacks.
In studies presented by Janssen, thirteen patients who were taking Invokana suffered cardiovascular events. Further, Wolfe demonstrated that the heart attack risk (measured by increase in hematocrit) for Invokana (canagliflozin) users was as much as one and a half times greater than those in the gliflozin group. Hematocrit is the concentration of red bloods cells. In women, the normal concentration of hematocrit is 40 percent and the normal concentration in men is 45 percent. Any levels higher than this increase the risk of a blood clot which, in turn, causes a heart attack or stroke.
Wolfe believed that a full one-quarter of Invokana users would develop a hematocrit of 47 percent—a “very dangerous range.” FDA biostatistician Dr. Mat Soukop testified before the panel regarding the number of patients taking Invokana who suffered a cardiovascular event during the first 30 days of taking the drug. Soukop placed Invokana’s Hazard Ratio at 6.9, giving patients taking Invokana a significant increase in the risk of a cardiovascular event during the first 30 days of treatment. After the initial thirty days, those cardiovascular risks appeared to decrease.
FDA Approves Invokana; Janssen Must Monitor Invokana-Related Adverse Event Reports
Despite the information presented regarding Invokana’s cardiovascular risks, the FDA approved the drug, only requiring Janssen to monitor adverse events related to the drug. Janssen was also required to conduct a post-market study to determine how many patients taking Invokana experienced a heart attack, however the company was given four years to complete the study.
Janssen was also asked to complete the ongoing Cardiovascular Assessment Study (CANVAS) which has 4,330 individuals with cardiovascular disease or a high risk for cardiovascular disease enrolled. Interim data submitted to the FDA from CANVAS determined that, overall, Invokana was not associated with an increased risk of heart attack, however a 46 percent elevated risk of stroke, especially within the first thirty days of treatment was seen in those taking the drug. Symptoms of a heart attack may include shortness of breath, chest pain, chest discomfort, extreme fatigue, dizziness, nausea, vomiting and cold sweats as well as any sudden, new symptom.
More SGLT-2 Inhibitor Drugs Quickly Gain FDA Approval
Although Invokana was the first SGLT-2 inhibitor drug approved by the FDA—and still has the lion’s share of the market, five more similar drugs followed quickly. Farxiga was approved in January, 2014, Jardiance in August, 2014, Invokamet later in August, 2014, Xigduo XR in October, 2014, and Glyxambi in February of 2015. Glyxambi contains both an SGLT-2 inhibitor and a DPP-4 inhibitor while Xigduo XR and Invokamet add metformin to the SGLT-2 inhibitor.
Did Johnson & Johnson Fail to Warn Consumers Potential Invokana Risks?
It seems likely that Janssen and its parent company, Johnson & Johnson were aware of the potential heart attack and stroke risk associated with Invokana. If this can be proven, future lawsuits are likely to claim failure to warn. The literature included with Invokana does not specifically warn patients of the risks of heart attack, stroke, ketoacidosis and kidney failure. If these risks had been clearly stated, it is unlikely many patients taking Invokana would have done so, particularly when it has not been shown these new drugs have significant benefits over older diabetic drugs.