Efficacy of Aficamten in Patients with Obstructive Hypertrophic Cardiomyopathy and Mild Symptoms: Results from the SEQUIOA-HCM Trial

Abstract Background and Aims Patients with obstructive hypertrophic cardiomyopathy (oHCM) treated with aficamten in SEQUOIA-HCM (NCT05186818) demonstrated marked improvement in symptoms and functional capacity. This analysis explores whether oHCM and mild symptoms experience similar clinical benefit with aficamten as patients with more advanced limitation. Methods Patients in SEQUOIA-HCM (N=282) were grouped at baseline according to symptom severity. Mild symptoms (n=118) were defined as New York Heart Association (NYHA) class II and Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS) ≥80, and moderate to severe symptoms (n=150) as NYHA class II/III/IV and KCCQ-CSS <80. Primary endpoint was change in peak oxygen uptake (pVO2) from baseline to Week 24; secondary endpoints included change in NYHA class, KCCQ-CSS, outflow tract gradients, and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Results In aficamten-treated patients, change at Week 24 was not different between moderate to severe (1.8 mL/kg/min; n=71) and mild (1.6 mL/kg/min; n=62) symptom groups (p=0.8). Likewise, the change in secondary endpoints (NYHA class, resting or Valsalva gradients, and NT-proBNP) did not differ significantly between the two symptom groups. Both groups experienced statistically significant improvements in KCCQ-CSS, but the extent of improvement was greater in the advanced symptom group (p=0.02 for interaction). Treatment-emergent serious adverse events were infrequent in both groups. Conclusions Patients with oHCM and mild symptoms treated with aficamten achieved significant improvement across a range of clinically relevant outcomes, and generally similar to patients with more advanced symptoms. Less severely symptomatic patients could be considered for aficamten treatment.