This week, Johnson & Johnson was celebrating results from its CANVAS and CANVAS-R studies, showing that its diabetic drug Invokana (canagliflozin) reduced the risk of heart attacks and strokes by 14%. Those results were presented on Monday at the 77th annual meeting of the American Diabetes Association. That compared very favorably with rival prescription medication Jardiance (empagliflozin), a product of Eli Lilly and Company. The rate of adverse cardiac events among Invokana patients was nearly two-thirds lower, while the figure for Jardiance was 38%.
The hope for J&J was that it would increase sales of SGLT-2 inhibitors in general – and Invokana in particular. The stakes are high; currently, drugs of the gliflozin class make up 6% of a worldwide market in diabetic drugs of $40 billion, a figure that is expected to grow over the next several years. However, J&J shouldn't be popping the champagne corks. Although Invokana may help reduce the risk of adverse cardiovascular (CV) events, it still increases the risk of foot and lower limb amputations by 100%.
On the other hand, Jardiance and similar competing drugs do not seem to carry that same risk – which bodes ill for J&J's hopes of increased market share. Dr. Tom Donner, who heads the Diabetes Center at Johns Hopkins, told Bloomberg, “To date, we have not seen an increase in the amputation signal with the other drugs...that does influence your prescribing decision.” In addition to the amputation risk, there also remains the issue of increased bone fracture risk as well as decreased bone density in the hip and lumbar spine region. This side effect can appear as soon as 12 weeks after starting the medication.
Invokana was the first sodium glucose co-transporter 2 inhibitor (SGLT-2) to win FDA approval back in 2013. Hailed as a “miracle drug” at the time, the drug essentially eliminates excess blood sugar (glucose) through the urine. However, it was not long before patients began developing ketoacidosis, a dangerous rise in blood acidity, as a result of taking Invokana. Ketoacidosis can also lead to a serious kidney infection, known as pyelonephritis, which can cause complete loss of kidney function.
It seems that most of Big Pharma's new products offer trade-offs of one kind or another. In this case, the choice is protecting the heart at the expense of the lower limbs. Speaking to Forbes, endocrinologist Dr. John Buse summed it up this way: “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.”