Johnson & Johnson's type 2 diabetes drug Invokana has been shown to significantly reduce heart events in patients with the metabolic disease but raises risk for amputations.
Data presented at the annual meeting of the American Diabetes Association on Monday, June 12, showed that the drug can significantly reduce risk of serious heart problems in type 2 diabetes patients with established or elevated risk for heart disease.
The diabetes drug was also found to reduce risk of hospitalization for heart failure and provides protection against kidney function decline. Unfortunately, use of the drug also comes with serious cost.
Risk Of Amputations
The risk of amputations of toes or feet was double in patients who took Invokana compared with those who took placebo in studies that involved 10,142 type 2 diabetes patients.
The study was conducted to show that Invokana, also known chemically as canagliflozin, do not cause heart complications. Results shown that it reduced the combined risk of nonfatal heart attack, heart-related death, and nonfatal stroke by 14 percent compared with placebo.
For every three strokes, heart attacks, or cardiovascular deaths prevented by the drug, though, there were two amputations, 71 percent of which were of toes or the lower foot.
Invokana, Jardiance, And Farxiga
The risk for amputations boosted J&J's rivals Eli Lilly and Boehringer Ingelheim drug Jardiance, which was already shown effective at reducing risk of cardiovascular death sans the risk for amputations. In a study involving 7,000 patients, which was published in New England Journal in 2015, investigators reported that Jardiance reduced risk for heart attack, strokes, and cardiovascular deaths by 14 percent, which is the same with Invokana.
Invokana, Jardiance, and AstraZeneca Plc's Farxiga belong to a newer class of type 2 diabetes drugs known as SGLT-2 inhibitors, which work by removing blood sugar through the urine, thereby preventing the kidney from absorbing from the blood. The treatment lowers blood sugar but leads to more urinary tract infections and weakened bones.
Scientists are not yet sure why these drugs could prevent cardiovascular disease. It is neither clear why one of these drugs can raise risk for amputations, which experts said highlights the needs for a test on each of these medicines.
Benefits vs Risks Of Using Invokana
Invokana study lead investigator Bruce Neal, from George Institute for Global Health in Sydney, Australia, and colleagues argued that the results of the study showed Invokana has clear benefit compared with current diabetes treatments despite the amputation risks.
"It's fair to say we're clearly preventing more major cardiovascular events than we're going to be causing amputations. I think the balance of benefits vs risks is going to fall pretty heavily in favor of SGLT2 inhibition, even with an amputation risk," Neal said.
Some experts, however, do not share the same opinion.
"Personally, I would much rather have a small heart attack than lose a toe," said John Buse, from University of North Carolina at Chapel Hill. "And I think I would much rather have a big heart attack than lose a leg."