AT THE ESC CONGRESS 2015
LONDON – Further data from two large-scale diabetes trials continue to indicate that there is no increased risk for heart failure with either lixisenatide or sitagliptin compared to placebo.
The findings from ELIXA (the evaluation of lixisenatide in acute coronary syndromes) and TECOS (the Trial Evaluating Cardiovascular Outcomes With Sitagliptin), presented at the annual congress of the European Society of Cardiology, provide reassuring evidence of the cardiovascular safety of both drugs, and add to the trials’ results previously presented at the 2015 annual scientific sessions of the American Diabetes Association, according to the key investigators for the separately-run trials.“ELIXA demonstrates the cardiovascular safety of lixisenatide,” Dr. Eldrin Lewis, associate professor of medicine at Harvard Medical School and of Brigham and Women’s Hospital in Boston. “Additional analyses indicate safety with respect to heart failure events as well as all-cause mortality, and the hazard ratio after heart failure hospitalizations demonstrate that this endpoint is very meaningful in diabetes as it is in other populations” he added. Furthermore, the neutral effects of lixisenatide were seen across a wide spectrum of heart failure risk.
TECOS investigator Dr. Paul Armstrong of the University of Alberta in Canada noted similar safety findings with sitagliptin. “We found no increase in the risk of heart failure or related adverse outcomes after sitagliptin therapy,” he said at a press briefing. “We can safely conclude that sitagliptin can be used in patients with type 2 diabetes without concern for worsening heart failure.”
ELIXA and TECOS were two phase 3, randomized, double blind placebo-controlled trials specifically designed to look at cardiovascular outcomes after treatment with the glucagon-like peptide 1 (GLP-1) receptor agonist lixisenatide (intended trade name Lyxumia) or the dipeptyl peptidase 4 (DPP-4) inhibitor sitagliptin (Januvia). The trials enrolled 6,068 and 14,671 patients, respectively, and were performed in the wake of prior trials that had suggested an increased risk for hospitalization for heart failure in patients treated with other DPP-4 inhibitors including saxagliptin (Onglyza) in the SAVOR-TIMI 53 trial and alogliptin (Nesina) in the EXAMINE (Examination of Cardiovascular Outcomes with Alogliptin versus Standard of Care) trial.Although powered to show superiority of lixisenatide versus placebo in terms of cardiovascular safety, ELIXA was only able to establish noninferiority (HR, 1.02), but results were below limits for noninferiority set by the United States Food and Drug Administration, Dr. Lewis observed. In the updated analysis of ELIXA there was no difference between treatment with the lixisenatide and placebo for the primary composite cardiovascular endpoint plus heart failure hospitalization (hazard ratio, 0.97, 95% confidence interval 0.85-1.10) after 3 years of follow-up. There were also no differences in the rates of heart failure hospitalization (HR, 0.96, 95% CI 0.75-1.23), the primary endpoint plus heart failure hospitalization and coronary revascularization (HR=1.00, 95% CI 0.90-1.11), or death from any cause (HR, 0.94, 95% CI 0.78-1.13).Although the risk for heart failure hospitalization was found to be nine times higher in patients who had a prior history of heart failure in ELIXA than in those who did not there was there was no difference between treatment with the GLP-1 agonist or placebo in patients with (9.7% vs. 10.2%, HR, 0.93, 95% CI 0.66-1.30) or without (2.4% vs. 2.5%, HR, 0.97, 95% CI 0.67-1.40) a history of the disease.
The primary findings of TECOS have been published ( doi:10.1056/NEJMoa1501352 ) and showed sitagliptin to be noninferior to placebo for the primary composite cardiovascular endpoint (HR,0.98; 95% CI, 0.88-1.09; P less than .001). Heart failure hospitalization rates were similar (HR, 1.00; 95% CI, 0.83-1.20; P = .98).
In the updated analysis of TECOS, the prespecified secondary endpoint of time to first hospitalization for heart failure did not differ between the placebo and sitagliptin arms (HR, 1.0; 95% CI, 0.84-1.20, P = .95), nor were there any differences between the treatments in terms of other prespecified secondary endpoints of hospitalization for heart failure or cardiovascular death (HR, 1.02, 95% CI 0.90-1.14, P =.74), or hospitalization for heart failure or all-cause death (HR, 1.00, 95% CI 0.90-1.11, P = .93).
Dr. Armstrong acknowledged that the findings of TECOS were in contrast to the SAVOR-TIMI 53 and EXAMINE trials but that this could be due to several factors: differences in the patients enrolled, the background care provided, and variation in the acquisition or definition of heart failure events between the trials. It could also be due to intrinsic differences among the DPP-4 inhibitors themselves or “chance.”
Dr. Gabriel Steg of Hôpital Bichat in Paris, France who provided independent comment after the presentation of the ELIXA data questioned the value of continuing to perform large-scale noninferiority studies assessing the cardiovascular safety of novel diabetes medicines. More than 150,000 patients have been studied in such trials to date which have shown noninferiority for cardiovascular outcomes.
“Non-inferiority trials are often mistakenly being interpreted as ‘lack of efficacy’ trials and can among nonspecialists generate skepticism regarding treatment of diabetes or the need to control glycemia,” he said. “My conclusion would be to suggest that it is time to stop wasting resources on noninferiority trials and to work on truly improving diabetes care.”
ELXIA was sponsored by Sanofi. Dr. Lewis disclosed receiving research funding from Sanofi, and other drug companies. TECOS was sponsored by Merck. Dr. Armstrong disclosed receiving research funding, educational grants and consulting fees from Merck as well as other companies. Dr. Steg had received research grants from and has acted as a consultant for Sanofi, Merck, and other companies.