Type 2 diabetes drug Invokana (canagliflozin) was the subject of the Canagliflozin Cardiovascular Assessment Study (CANVAS) and the CANVAS renal-end-points trial (CANVAS-R). While it was recently shown to have significant cardiovascular benefits, it also carries double the risk of lower-limb amputations.
In terms of cardiovascular event reduction, Invokana was shown to result in “a 14% reduction in risk for a composite score on CV mortality as well as nonfatal myocardial infarction and stroke, with each measure contributing to the positive score,” according to a recent article on the topic.
This 14% risk reduction perfectly matches that of Jardiance (empagliflozin), another type 2 diabetes drug belonging to the SGLT2 inhibitors class of drugs. This suggests that there may be a similar effect for other drugs in this class, such as Farxiga (dapagliflozin). However, we won’t know for sure until 2019 when the results of the Farxiga study are released.
Additionally, when comparing Jardiance and Invokana, “Jardiance was more effective in cutting the risk of death (-38%) compared to a much more modest 13% reduction for Invokana.”
Invokana was also “linked to a significantly higher risk of amputations, a safety concern that has already triggered a black box warning.” While the total number of amputations was small, it was double that of the placebo group. For more information on this topic, see my previous article, “Risk of Lower Limb Amputations Doubled with Invokana and Invokamet Use.”
A recent Forbes article provides more information on the cardiac benefits and amputation risks:
For every three heart attacks, strokes, or cardiovascular deaths prevented by Invokana, there were two amputations, 71% of them of toes or the lower foot, according to the results of the 10,142-patient study, which was funded by Johnson & Johnson…
Heart attacks were far more common than amputations. For every year patients took the drug, there were 31.5 heart attacks, strokes, or cardiovascular deaths per 1,000 patients in the placebo group and 26.9 in the group that took Invokana, a 14% decrease. But, there would be 3.4 amputations per 1,000 patients in the placebo group and 6.3 amputations per 1,000 patients among those who received Invokana – a doubling of risk that held true for both minor amputations (think toes) and major ones (think legs).
John Buse, the chief of endocrinology at UNC – Chapel Hill provided his opinion on the matter, “Personally, I would much rather have a small heart attack than lose a toe…And I think I would much rather have a big heart attack than lose a leg.” He anticipates a significant debate, saying that the benefits and harms are most likely “over- and under-estimated in each study.”
We will continue to monitor the medical literature on the potential risks and benefits of Invokana and similar SGLT2 drugs.
Currently, we are investigating cases concerning Invokana / Farxiga / Jardiance / Invokamet / Xigduo / Glyxambi / Synjardy / Qtern. See our website for more information on these drugs, and for our free case evaluation.
Written by: Heather Helmendach, Legal Assistant
Law Offices of Thomas J. Lamb, P.A.
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