A new class of diabetes medicines is heavily advertised on TV and shows great promise in getting patients' blood sugar levels down, but a safety announcement from the Food and Drug Administration warns that one of the drugs, Johnson & Johnson's Invokana, doubles those patients' chance of needing parts of their legs or feet amputated.
Among almost 6,000 patients receiving canagliflozin in the two trials, rates of amputations were 5.9 and 7.5 per 1,000 patient-years, compared with 2.8 and 4.2 per 1,000 patient-years in the placebo groups.
Some Invokana patients suffered more than one amputation, with a portion of those patients needing amputations on both limbs.
The FDA said that the trials showed amputations occurred about twice as often in type 2 diabetes patients who were treated with the medication also called canagliflozin, as those who were given placebo.More news: Penn State's Cole Miller in contention at NCAA golf regional
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SGLT2 - sodium-glucose co-transporter 2 - is a protein that facilitates glucose reabsorption in the kidneys. It lowers blood sugar by causing the kidneys to remove sugar from the body through the urine.
Now, though, "the increasingly differentiated labels and data to date suggest that ..."
The warning comes after the agency reviewed data from two randomized, placebo controlled trials (CANVAS and CANVAS-R) that showed rates of lower-extremity amputations were doubled in the active drug groups, irrespective of dose.
J&J's Janssen subsidiary began the Canvas trial in December 2009 to examine the potential cardiovascular benefit of Invokana. Untreated, type 2 diabetes can lead to serious problems, including blindness, nerve and kidney damage, and heart disease. Jardiance was the first Type 2 diabetes drug to get approval for cutting the risk of cardiovascular death. "We believe a dramatic impact on the class is unlikely", he said, noting that the company's situation "could be further mitigated by a directionally positive result" from the outcomes studies on CV risk reduction.
"So even if Jardiance were to capture 100% of Invokana's estimates sales of $1 billion in 2017 in the immediate future, a major slowdown in category growth likely would be a bigger issue relative to consensus estimates", he said.