As more studies solidify the link between Invokana (or canagliflozin) and diabetic ketoacidosis (DKA), more patients are filing lawsuits alleging that drugmaker Janssen failed to warn adequately about these side effects. Hundreds such lawsuits comprise the Invokana multi-district litigation (MDL) in New Jersey.
These cases received a boost earlier this year when the U.S. Food and Drug Administration (FDA) added a black box warning highlighting Invokana’s heightened risks of foot and leg amputations.
Amputation Risk May Be Twice as High
“Some patients had more than one amputation, some involving both limbs.”
The FDA required that warning after two different clinical trials, CANVAS and CANVAS-R, “showed that leg and foot amputations occurred about twice as often in patients treated with canagliflozin compared to patients treated with placebo.”
Each trial took place over the course of a year. The CANVAS study found:
- Out of every 1,000 patients taking placebos, 2.8 required amputations
- Out of every 1,000 patients taking canagliflozin, 5.9 (more than twice as many) required amputations
While the CANVAS-R study was not quite as grim, it also found an elevated amputation risk for patients taking Invokana:
- Out of every 1,000 patients taking placebos, 4.2 required amputations
- Out of every 1,000 patients taking canagliflozin, 7.5 required amputations (a 79 percent increase)
The most common amputations were of the foot or toe. Alarmingly, the FDA also notes, “Some patients had more than one amputation, some involving both limbs.”
Sales Dip in Light of Frightening Studies
Another study, which appeared in The Lancet Diabetes & Endocrinology, also proved worrisome for Invokana users.
That study, which appeared in August 2017, found that of the 66 SGLT2 inhibitor-related amputations, “Most of the available reports (57 [86%] of 66) listed canagliflozin as a suspect or concomitant drug.”
In the first quarter of 2017, Invokana sales dropped by 10 percent.
The FAERS assessment finds that the rate of amputation among patients on canagliflozin is “significantly higher” than others, and concludes, “…use of canagliflozin, but not dapagliflozin or empagliflozin, might be associated with an increased risk of amputations.”
Not surprisingly, the CANVAS and FAERS analyses compelled some doctors to take their patients off Invokana. Dr. Steve Nissan told MedPage Today that he is “uncomfortable prescribing [canagliflozin] in view of the amputation risk.”
From 2014 to 2015 Invokana sales more than doubled, from $586 million to $1.31 billion. But from 2015 to 2016 sales barely increased, and in the first quarter of 2017 they dropped by 10 percent.
With a new black box warning, scientists sounding the alarm, and alternative drugs emerging, Invokana is likely past its prime in terms of prescriptions and sales. But what about all the patients who have already taken it and suffered life-altering side effects?
Invokana Bellwether Trials Set for Fall 2018
Hundreds of Invokana patients have filed lawsuits against Janssen Pharmaceuticals (a subsidiary of Johnson & Johnson). They allege that Janssen misrepresented the drug’s risks and failed to warn patients about side effects like lower extremity amputations.
The recent $28 million Xarelto verdict could compel J&J to settle.
Bellwether trials are not scheduled to begin until September 2018, but major losses like the recent $28 million Xarelto verdict could compel J&J to settle these cases before they make it to court.