The cardiovascular outcome trial results for a fourth sodium-glucose cotransporter 2 (SGLT2) inhibitor, ertugliflozin, were most notable for their consistency with the four prior, similar trials run on the three other drugs from this class on the U.S. market, canagliflozin, dapagliflozin, and empagliflozin, further solidifying the important role this drug class has recently taken on for patients with type 2 diabetes.
Dr. Christopher Cannon
But the ertugliflozin results, which showed statistically significant superiority to placebo for just one endpoint, hospitalization for heart failure, made it unclear whether clinicians will regard ertugliflozin as the top agent from this class to prescribe.
“Our big takeaway is that the findings are consistent with what’s been seen in the other studies” of cardiovascular and renal outcomes in the EMPA-REG OUTCOME study of empagliflozin (N Engl J Med. 2015 Nov 26;373[22]:2117-28 ), the CANVAS (N Engl J Med. 2017 Aug 17;377[7]:644-57) and CREDENCE (N Engl J Med. 2019 June 13;380[24]:2295-306 ) studies of canagliflozin, and the DECLARE-TIMI 58 trial with dapagliflozin (N Engl J Med. 2019 Jan 24;380[4]:347-57), Christopher P. Cannon, MD, said at the virtual annual scientific sessions of the American Diabetes Association.
The cardiovascular outcome trials (CVOTs), mandated in 2008 by Food and Drug Administration guidance for type 2 diabetes drugs that is now in the process of undergoing an update, have had the main goal of proving safety, and the primary endpoint of the new ertugliflozin trial, VERTIS-CV, was noninferiority to placebo when used on top of standard type 2 diabetes medications for the combined endpoint of cardiovascular death, nonfatal MI, or nonfatal stroke.
Key findings
Both of the tested dosages of ertugliflozin, 5 mg and 15 mg daily, met this endpoint, with event rates over a median 3.0 years of follow-up that ran very close to the placebo rate, clearly proving noninferiority. But the results showed no suggestion of superiority in a study that randomized 5,499 patients to either of the ertugliflozin regimens and 2,747 to placebo, reported Dr. Cannon, a cardiologist and professor of medicine at Harvard Medical School, Boston.
The primary outcome also showed similar event rates for each component of the composite endpoint, and subgroup analysis showed consistent results from ertugliflozin, compared with placebo, regardless of study-cohort subdivision by demographic, clinical, or treatment factors.
The trial design called for a hierarchical sequence of secondary-outcome superiority analyses, starting with the impact of ertugliflozin on cardiovascular death or heart failure hospitalization, and for this outcome ertugliflozin showed a point estimate of a 12% relative risk reduction, compared with placebo-treated patients, but this difference was not statistically significant. This meant that all subsequent superiority analyses in this trial could only be hypothesis generating and not definitive.
This negated the statistical validity of the only statistically significant treatment difference between ertugliflozin and placebo seen in VERTIS-CV, for the outcome of hospitalization for heart failure, where ertugliflozin treatment cut this outcome by 30%, compared with placebo patients. The rate of cardiovascular death alone, as well as a renal composite endpoint each showed no statistically significant benefit of ertugliflozin, compared with placebo, although the renal endpoint came close, with ertugliflozin reducing the combined rate of renal death, need for dialysis, need for renal transplant, or a doubling of serum creatinine from baseline by 19%, compared with placebo (P = .08).