LAS VEGAS – Additional findings from the landmark PARADIGM-HF trial presented at the annual meeting of the Heart Failure Society of America provided what many observers deemed a persuasive case for the novel angiotensin receptor neprilysin inhibitor known for now as LCZ696 as deserving of a level I indication in the next update of the major heart failure management guidelines.
Dr. Milton Packer
At a special session added late to the meeting program in the wake of the spectacularly positive top-line results of PARADIGM-HF presented just a few weeks earlier at the European Society of Cardiology meeting in Barcelona, an international panel of heart failure heavyweights tackled questions about the study’s implications, including whether the results need replication in a second randomized controlled trial before LCZ696 can win regulatory approval. And once approved, should guidelines committees give it a level I, must-use indication? How applicable are the PARADIGM-HF results to the broader population of heart failure patients, and in particular black patients and older individuals with class III/IV heart failure? And what about patients with heart failure with preserved ejection fraction (HFpEF) ?
In other words, does PARADIGM-HF, with more than 8,400 randomized subjects, represent a true paradigm shift in heart failure management?
For coprincipal investigator Dr. Milton Packer, the answer is a resounding yes.
“For the past 25 years, the magnitude of the effect of ACE inhibitors on cardiovascular mortality – about an 18% reduction – has created an ethical mandate for their use in all patients with chronic heart failure who could tolerate treatment with these drugs. The finding that LCZ696 has a 20% greater effect on cardiovascular mortality than ACE inhibitors strongly supports the conclusion that LCZ696 should replace the current use of ACE inhibitors and angiotensin receptor blockers in the management of chronic heart failure,” said Dr. Packer, professor and chair of the department of clinical sciences at University of Texas Southwestern Medical Center, Dallas.
Naseem S. Miller/Frontline Medical News
Dr. John McMurray
His coprincipal investigator, Dr. John J.V. McMurray, cited the statistical strength of the PARADIGM-HF results for the primary composite outcome of cardiovascular death or heart failure hospitalization, which had an extraordinary P value of .0000004, in making the case that the trial findings are sufficient to win regulatory approval without a confirmatory study.
He noted that the regulatory standard in the United States and Europe is that a positive clinical trial having a P value of less than .05 requires replication in a second study that also yields outcomes with a P value of less than .05.
“If, however, you have a large single trial, you can win approval by meeting a standard of P less than .00125. The strength of the result of PARADIGM-HF, with a P of .0000004, is equivalent to between four and five single trials replicated at P less than .05. And for the endpoint of cardiovascular mortality, where the PARADIGM-HF result was significant at a P of .00008, that’s equivalent to between two and three trials replicated at P less than .05. So in my view PARADIGM-HF easily meets the criteria for a level IA indication,” said Dr. McMurray, professor of cardiology at the University of Glasgow.
He presented for the first time a new analysis with a major wow factor. This was an imputed placebo analysis providing the answer to a question many cardiologists have asked him since the presentation of the top-line PARADIGM-HF results in Barcelona: namely, how would LCZ696 have stacked up in a placebo-controlled trial?
Such a study wouldn’t be ethical now, of course, but it’s possible to make inferences by comparing LCZ696’s superiority to enalapril at 10 mg b.i.d. in PARADIGM-HF to enalapril’s performance at the same dose relative to placebo in the earlier 2,569-patient SOLVD-Treatment trial, which featured the same composite primary endpoint (N. Engl. J. Med. 1991;325:293-302).
In SOLVD-Treatment, enalapril resulted in a 28% relative risk reduction in the composite endpoint, compared with placebo. Through indirect comparison, LCZ696 would have an imputed 43% relative risk reduction, compared with placebo. For the endpoint of cardiovascular mortality, enalapril showed a 17% risk reduction relative to placebo; when the PARADIGM-HF results are factored in, this translates to an inferred 34% relative risk reduction for LCZ696 versus placebo.
Similarly, in the CHARM-Alternative trial (Lancet 2003;362:772-6), which featured 2,028 patients on more contemporary guideline–recommended background therapy than in SOLVD-Treatment, patients on the angiotensin receptor blocker candesartan showed a 23% relative risk reduction in the composite endpoint, compared with placebo, along with a 15% reduction in cardiovascular mortality. In the imputed placebo analysis, this translated to relative risk reductions of 49% and 34%, respectively, for LCZ696 versus placebo.