Long-Term Data Confirms CAMZYOS® Efficacy and Safety in Symptomatic oHCM Patients

Bristol Myers Squibb recently revealed long-term follow-up results from the EXPLORER-LTE cohort of the MAVA-Long-Term Extension (LTE) study, assessing CAMZYOS® (mavacamten) in adults with symptomatic obstructive hypertrophic cardiomyopathy (oHCM) classified as New York Heart Association (NYHA) class II-III. The new data, showcased at the European Society of Cardiology (ESC) Congress in London, confirm the drug's established efficacy and safety profile. CAMZYOS, a cardiac myosin inhibitor, is recommended in ESC and AHA/ACC clinical guidelines for symptomatic oHCM when first-line therapy fails. This positions CAMZYOS as a standard care option for the condition.

Patients undergoing continuous treatment with CAMZYOS for up to 3.5 years (180 weeks) showed consistent and sustained improvements in several echocardiographic measures and biomarkers. Notable improvements were observed in resting left ventricular outflow tract (LVOT) gradient, Valsalva LVOT gradient, left atrial volume index, and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels. Furthermore, patients reported enhanced symptoms and functional capacity, with many achieving NYHA class I status. The drug's safety profile remained consistent over the 3.5-year period, with no new safety issues noted.

Dr. Pablo García-Pavia, head of the Inherited Cardiac Diseases and Heart Failure Unit at Hospital Universitario Puerta de Hierro and a professor at the Spanish Cardiovascular Research Institute, emphasized the significance of these findings. "The consistent and sustained improvements in multiple cardiac measures over more than three years with CAMZYOS show that this therapy meets an important treatment need for patients with symptomatic obstructive HCM," he said. García-Pavia highlighted the long-term benefits of CAMZYOS and its inclusion in ESC clinical guidelines as essential for managing this chronic condition.

The study's data cutoff showed that 211 of 231 patients initially enrolled in MAVA-LTE, part of which is the EXPLORER-LTE cohort, were on CAMZYOS. Of these, 185 and 99 patients reached Week 156 and Week 180, respectively. Key findings indicated sustained improvements in echocardiographic measures and biomarkers from baseline to Weeks 156 and 180. Specifically, there was a reduction of 55.3 mmHg in the Valsalva LVOT gradient at both weeks and a reduction of around 40 mmHg in mean resting LVOT gradient. The left atrial volume index also decreased notably, while the mean left ventricular ejection fraction (LVEF) remained within the normal range despite a slight decrease.

At Week 180, most patients (66.3%) achieved NYHA class I. Nearly half of the patients (46.8%) attained a complete response, defined as NYHA class I and a Valsalva LVOT gradient of ≤30 mmHg, maintained until data cutoff. Patient-reported outcomes via the HCM Symptom Questionnaire (HCMSQ) indicated notable improvements in shortness of breath scores from baseline, sustained through Weeks 156 and 180.

Dr. Roland Chen, senior vice president and head of Immunology, Cardiovascular & Neuroscience Development at Bristol Myers Squibb, remarked on the significance of these long-term results, stating, "These results, representing the longest duration of follow-up of the Phase 3 EXPLORER study to date, further reinforce the established safety and efficacy profile of CAMZYOS." Chen highlighted that CAMZYOS is the first and only approved cardiac myosin inhibitor for symptomatic obstructive HCM, with thousands of patients treated globally.

The EXPLORER-LTE analysis revealed no new safety concerns with CAMZYOS treatment. A total of 20 patients (8.7%) experienced temporary reductions in LVEF below 50%, all of whom recovered after treatment interruption, with 14 patients resuming CAMZYOS therapy.

CAMZYOS, the first cardiac myosin inhibitor approved in the U.S. for treating adults with symptomatic NYHA class II-III oHCM, has also received regulatory approvals across multiple countries. The drug functions by modulating myosin activity to reduce dynamic LVOT obstruction and improve cardiac filling pressures in HCM patients.