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Saxagliptin, alogliptin show cardiovascular safety in randomized trials
Major finding: Percentage of treatment group vs. placebo group patients reaching a composite cardiovascular endpoint in SAVOR-TIMI 53: 7.3% vs. 7....
Signals for canagliflozin, too?
SAVOR-TIMI 53 and EXAMINE provide the first results from what are more than a dozen large studies – involving more than 100,000 patients – launched recently to look for adverse cardiovascular effects from drugs in six different diabetes drug classes, according to Dr. Sanjay Kaul, who also spoke at EASD. He presented results from a meta-analysis he performed on results from nine phase III and phase II trials of canagliflozin (Invokana), an agent from the sodium-glucose cotransporter 2 (SGLT2) inhibitor class and approved by the FDA last March for treatment of type 2 diabetes, the first drug in that class to get U.S. marketing approval.
In the largest of these trials, CANVAS – the cardiovascular-assessment study for canagliflozin set up by the drug’s developer, Janssen – treatment with canagliflozin linked with a statistically significant, sixfold increase in cardiovascular events during the first 30 days of treatment, a link that then disappeared with longer-term treatment in patients with high CV risk. (Complete results from CANVAS have not yet been reported.) But Dr. Kaul did not see a similar excess in the other eight studies.
The canagliflozin meta-analysis also showed a nonsignificant, 46% increased risk of stroke in patients on the drug, a signal not seen in any other individual cardiovascular endpoint. Dr. Kaul analyzed data from 14 phase II and III trials for a second SGLT2 inhibitor drug, dapagliflozin, which showed no suggestion of causing any cardiovascular risk.
The canagliflozin risk signals are not reasons to stop using the drug or to withdraw it from the market, said Dr. Kaul, a member of the FDA’s Endocrinologic and Metabolic Drugs Advisory Committee. The early signal of risk in CANVAS was not seen in any other study, and it may have been a statistical artifact, he said.
He said that signals of risk must be considered relative to a drug’s benefit. Applying the same standard of cardiovascular harm to drugs that are highly effective and to drugs that are not very effective "doesn’t make sense," he said. "A risk-benefit trade-off depends on the benefit. If you have a diabetes drug that lowers hemoglobin A1c by 1.5%-2% I’m willing to accept greater harm than I would from a drug that produced a 0.5% drop in hemoglobin A1c."
A final rosiglitazone thought
Dr. Kaul also made this observation about the rosiglitazone experience, which in retrospect produced "insufficient evidence to either incriminate or exonerate rosiglitazone," he said.
"That a diabetes drug [rosiglitazone] could have become a blockbuster without any established outcome benefits does not reflect well on the drug development and approval process. Equally lamentable is that this drug was virtually killed based on insufficient evidence and entrenched opinions."
Dr. Bhatt has received research grants from several companies, including AstraZeneca and Bristol-Myers Squibb (BMS), which market saxagliptin, and Takeda, maker of alogliptin. Dr. White is a safety consultant for several companies, including AstraZeneca and Takeda. Dr. Sattar is a consultant to several pharmaceutical firms, including AstraZeneca and BMS. Dr. Kaul is a consultant to Novo Nordisk, Sanofi, and Boehringer Ingelheim, and owns stock in Johnson & Johnson.
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