Evaluating the Efficacy, Safety, and Tolerability of Serelaxin When Added to Standard Therapy in Asian Patients With Acute Heart Failure: Design and Rationale of RELAX-AHF-ASIA Trial

Background Acute heart failure (AHF), a common and growing health concern worldwide, is associated with high risk of post-discharge rehospitalization and mortality. Existing evidence indicates potential therapeutic benefits of serelaxin in Caucasian AHF patients, but corresponding data in Asians remain scarce. RELAX-AHF-ASIA, a multinational, randomized, double-blind, placebo-controlled, phase III trial, will evaluate the effects of serelaxin on symptom relief and clinical outcomes in Asian AHF patients, with the use of novel assessments. Methods and Results Patients with AHF, systolic blood pressure ≥125 mm Hg, and mild to moderate renal dysfunction will be randomized within 16 hours of presentation to receive 48-hour intravenous infusion of 30 µg ⋅ kg⁻¹ ⋅ d⁻¹ serelaxin or placebo in addition to standard therapy. The composite primary end point includes: (1) treatment success (moderate/marked improvement in patient-reported dyspnea and physician-assessed signs of congestion on day 2); (2) treatment failure (in-hospital worsening of signs and/or symptoms of heart failure [HF] requiring intensification of intravenous HF therapy or mechanical ventilation, renal/circulatory support, rehospitalization due to HF/renal-failure, or death through day 5); and (3) unchanged status. Secondary end points include time to in-hospital worsening HF through day 5 and all-cause and cardiovascular deaths through day 180. Conclusions RELAX-AHF-ASIA, the largest randomized clinical trial in Asian AHF patients to date, has a novel composite primary end point and the potential to become a hallmark of AHF trials.