BMS Reports 3.5 Years of Sustained Efficacy for Camzyos in Cardiomyopathy

Bristol Myers Squibb has unveiled new long-term follow-up results for its cardiac myosin inhibitor, Camzyos (mavacamten), in patients with obstructive hypertrophic cardiomyopathy (oHCM). These findings, presented at the European Society of Cardiology (ESC) Congress, illustrate sustained improvements in echocardiographic measures, biomarkers, and symptoms for up to 3.5 years. This comes as competition from Cytokinetics' investigational drug, aficamten, looms.

Camzyos received FDA approval in 2022 to enhance functional capacity and symptoms in adults with symptomatic NYHA class II-III oHCM, based on data from the Phase III EXPLORER-HCM trial. In this trial, 37% of patients treated with Camzyos achieved the primary composite endpoint at 30 weeks. This endpoint included either a noticeable improvement in exercise capacity plus at least one NYHA class reduction or a significant enhancement in exercise ability without worsening of their condition. By contrast, only 17% of patients in the placebo group achieved the primary goal.

The new data from the MAVA-LTE study builds upon these initial findings. The cumulative analysis of up to 3.5 years of treatment shows sustained improvements in various echocardiographic measures, such as resting and Valsalva left ventricular outflow tract (LVOT) gradients. Additionally, the study reported consistent reductions in the left atrial volume index and NT-proBNP levels, alongside continued improvements in symptoms and functional capacity.

Specifically, 66.3% of patients had improved to NYHA class I by week 180, indicating a substantial symptom benefit. Investigators also observed that while the mean left ventricular ejection fraction (LVEF) decreased by 11% from the study's start to week 180, the average LVEF value during this period (63.9%) remained within the normal range. LVEF reductions of less than 50% occurred in 20 patients (8.7%) during long-term therapy, but these instances were described as "transient and reversible." Overall, 14.3% of patients experienced atrial fibrillation, 6.1% had episodes of cardiac failure, and 5.6% permanently discontinued treatment due to adverse events.

Meanwhile, Cytokinetics has provided detailed results from the Phase III SEQUOIA-HCM trial for its investigational cardiomyopathy drug, aficamten. The trial demonstrated that aficamten significantly improved exercise capacity and achieved statistical significance on all 10 secondary endpoints, indicating benefits in symptoms and function as early as two weeks after the first dose. Cytokinetics plans to submit an FDA filing this quarter and an EU application by the end of the year. The company positions aficamten as a potentially safer alternative to Camzyos, emphasizing that no instances of worsening heart failure or treatment interruptions due to low LVEF were observed during the SEQUOIA-HCM trial.

Following the SEQUOIA-HCM data release, a recent poll of US cardiologists revealed insights into the competitive landscape. Over 60% of respondents indicated they would be inclined to prescribe aficamten if it had less restrictive REMS requirements. However, a narrow majority expressed a preference for Camzyos over aficamten, possibly due to familiarity with the first-to-market drug.

These findings highlight the evolving landscape in the treatment of oHCM, with Bristol Myers Squibb's Camzyos demonstrating sustained long-term benefits and Cytokinetics' aficamten emerging as a potential competitor.