Pfizer Halts Eplerenone HF Trial Early Due to Drug Benefit

May 28, 2010

May 28, 2010 (New York, New York) — Pfizer is to halt recruitment of patients to the EMPHASIS-HF trial testing its selective aldosterone inhibitor eplerenone (Inspra) in mild heart-failure patients because of a significant benefit of the drug [1].

The trial, comparing eplerenone with placebo, when added to usual care for HF, had intended to enroll just over 3000 patients with NYHA stage 2 HF in 30 countries, with a planned end date of October 2011. Patients were randomized to receive either eplerenone 25 mg once daily or placebo, and at four weeks the dose of study drug could be increased to 50 mg per day if required. The trial was planned to continue until a total of 813 adjudicated primary end-point events were reported.

An interim analysis has shown that those treated with eplerenone have a significant reduction in risk of the primary end point, cardiovascular death or HF hospitalization, compared with those on placebo, according to a Pfizer statement.

The company says it is now working to ensure that all patients are informed of this decision, and an amendment to the protocol will be requested to allow all consenting patients to start treatment with eplerenone in an open-label extension of the study, after completing a close-out visit ending the double-blind, placebo-controlled phase.

Eplerenone, which has been called a "cleaner, safer" version of spironolactone, is approved for hypertension and for use in addition to optimal medical therapy early after acute MI in patients with congestive heart failure (CHF), on the basis of the Eplerenone Post-AMI Heart Failure Efficacy and Survival Study (EPHESUS) study. But eplerenone is not yet approved for use in the patient population being studied in EMPHASIS-HF, those with mild HF.