NEW ORLEANS – Dapagliflozin markedly reduces the risks of both major adverse cardiovascular events and heart failure hospitalization in the subset of patients with type 2 diabetes (T2D) and prior MI, according to a new subanalysis of the landmark DECLARE-TIMI 58 trial.
Dr. Remo H.M. Furtado
The effectiveness of dapagliflozin (Farxiga), an oral sodium glucose transporter-2 inhibitor (SGLT-2i), was particularly striking with regard to prevention of recurrent MI, Remo H.M. Furtado, MD, reported at the annual meeting of the American College of Cardiology.
“The 22% relative risk reduction in recurrent MI with dapagliflozin is comparable to other established therapies used in secondary prevention after MI, like DAPT [dual-antiplatelet therapy] and intensive lipid lowering,” observed Dr. Furtado of Brigham and Women’s Hospital, Boston.
Not bad for a drug developed as a glucose-lowering agent.
The new DECLARE-TIMI 58 subanalysis provides information that’s relevant to ACC guidelines issued in late 2018. The guidelines, in the form of an “expert consensus decision pathway,” emphatically recommend that all patients with T2D and known atherosclerotic cardiovascular disease (ASCVD) should have metformin as their first-line glucose-lowering agent, while at the same time giving serious consideration to the addition of either an oral SGLT-2i or a subcutaneously injected glucagonlike peptide–1 receptor agonist (GLP-1RA) with demonstrated cardiovascular benefit as a second glucose-lowering agent (J Am Coll Cardiol. 2018 Dec 18;72[24]:3200-23). The DECLARE-TIMI 58 subanalysis bolsters that guidance and shows, more specifically, that the cardioprotective benefits of dapagliflozin are significantly greater in T2D with prior MI than in those with known ASCVD but no history of MI, the cardiologist explained.
The main results of DECLARE-TIMI 58 have been published. The trial included 17,160 patients with T2D, 6,974 of whom had established ASCVD, while the remainder had multiple ASCVD risk factors. Participants were randomized to oral dapagliflozin at 10 mg/day or placebo on top of background guideline-directed medical therapy and followed for a median of 4.2 years. The dapagliflozin group had a 27% reduction in heart failure hospitalizations, compared with controls, but there were no significant between-group differences in the composite MACE (major adverse cardiovascular events) endpoint of cardiovascular death, MI, or ischemic stroke (N Engl J Med. 2019 Jan 24;380[4]:347-57).
Dr. Furtado presented a prespecified subgroup analysis focused on the 3,584 study participants with prior MI. Their rate of the composite endpoint of cardiovascular death, MI, or ischemic stroke was 15.2%, compared with 17.8% in controls, for a statistically significant and clinically meaningful 16% relative risk reduction and an absolute 2.6% risk reduction. Of note, the risk of recurrent MI was reduced by 22%. In contrast, there was no difference in MACE risk between the dapagliflozin and placebo groups in patients with no prior MI, even if they had established ASCVD.
A noteworthy finding was that the benefit in MACE reduction in patients with prior MI was greater in those who were closer in time to their most recent MI at enrollment in the study. Those who started on dapagliflozin within 12 months of their last MI had a 34% relative risk reduction in MACE, compared with placebo, while those who enrolled 12-24 months after their last MI enjoyed an even more robust 58% relative risk reduction on dapagliflozin. In contrast, patients who enrolled 24-36 months post MI had only a 17% relative risk reduction, and the 2,400 patients who enrolled more than 36 months after their last MI had a subsequent MACE rate no different from controls.
Session cochair Nadia R. Sutton, MD, a cardiologist at the University of Michigan, Ann Arbor, commented that she found this time-dependent benefit fascinating.
“Do you think this has anything to do with the escalation of other therapies, such as Plavix [clopidogrel]?” she asked.
Dr. Furtado replied, “This is a finding that we should interpret with a little bit of caution.” For one thing, patients in the acute phase of an MI were excluded from participation in the trial, so nothing is known about how they would fare on dapagliflozin. For another, only 844 of the 3,584 patients with T2D and prior MI had their most recent MI within 24 months of enrollment, so even though the differences were statistically significant, the confidence intervals are fairly wide.
That being said, the finding does underscore a truism about cardiovascular prevention: The higher the risk, the greater the benefit of effective therapy – and, of course, the initial months following an MI are a particularly high-risk period.
“Also, this finding is a caution to the clinicians to avoid clinical inertia in prescribing an SGLT-2i, because maybe you can get an early benefit if you prescribe the drug closer to the acute phase and not wait until some months after the patient has tried diet and exercise and so on,” he added.
With regard to the second coprimary endpoint comprising cardiovascular death or heart failure hospitalization in T2D patients with prior MI, the rate in the dapagliflozin group was 8.6%, a 19% relative risk reduction and absolute risk reduction of 1.9%, compared with the 10.5% rate with placebo.
Dr. Furtado noted that the main results of DECLARE TIMI-58 are consistent with a recent systematic review and meta-analysis of three randomized cardiovascular outcome trials of SGLT-2is for primary and secondary prevention of cardiovascular and renal outcomes in T2D. The meta-analysis included more than 34,000 patients, roughly half drawn from DECLARE-TIMI 58. SGLT-2i therapy reduced MACE by 14% in patients with established ASCVD but not significantly in those without. And the agents reduced the risk of cardiovascular death/heart failure hospitalization by 23%, regardless of whether or not patients had known ASCVD or a history of heart failure (Lancet. 2019 Jan 5;393[10166]:31-9).
Dr. Furtado reported serving as a consultant to AstraZeneca, which funded DECLARE-TIMI 58, as well as receiving direct institutional research grants from half a dozen other pharmaceutical companies.
Simultaneous with his presentation at ACC 2019 in New Orleans, the subanalysis results were published online (Circulation. 2019 Mar 18. doi: 10.1161/CIRCULATIONAHA.119.039996. [Epub ahead of print]).