Bristol Myers Squibb (NYSE: BMY) presented long-term clinical data for Camzyos (mavacamten) at the European Society of Cardiology (ESC) Congress 2026 in Munich, Germany. The results from the EXPLORER-LTE study demonstrate sustained efficacy and safety for symptomatic obstructive hypertrophic cardiomyopathy (oHCM) patients over five years.

The late-breaker presentation highlights the longest-running clinical development experience for a cardiac myosin inhibitor (CMI) in this indication. EXPLORER-LTE is the largest evaluation of symptomatic oHCM patients treated with Camzyos, which is now considered a standard of care for patients in New York Heart Association (NYHA) class II-III. Additional real-world evidence from the COLLIGO-HCM study further supports the drug’s effectiveness across diverse patient populations.

Clinical Efficacy and Safety

EXPLORER-LTE is a single-arm, open-label extension of the Phase 3 EXPLORER-HCM study, involving 231 patients who completed the initial trial. The data confirms that Camzyos effects are sustained with continuous treatment.

At 252 weeks, treatment resulted in significant reductions in left ventricular outflow tract (LVOT) gradients:

• Mean change in resting LVOT gradient: -38.7 mm Hg
• Mean change in Valsalva LVOT gradient: -55.6 mm Hg

Nearly all patients (97.4%) achieved a Valsalva LVOT gradient ≤ 30 mm Hg, the threshold for obstruction in oHCM. Functional improvements were also notable, with 69.6% of patients improving by at least one New York Heart Association (NYHA) class and 59.2% becoming asymptomatic.

Cardiac Function Metrics

Mean left ventricular ejection fraction (LVEF) decreased by 10.2% but remained within the normal range. No new safety signals were observed beyond those reported in the primary EXPLORER-HCM study.

Real-World Evidence

Data from the COLLIGO-HCM global retrospective study reinforces these findings in real-world settings. A complementary analysis from a German observational registry showed consistent NYHA class reductions across geographic populations. Additionally, a healthcare resource utilization study in Sweden highlighted the broader disease burden of oHCM, emphasizing the importance of accurate diagnosis.

What the Numbers Show

The high rate of asymptomatic outcomes (59.2%) alongside the near-universal achievement of the obstruction threshold (97.4% at ≤ 30 mm Hg) suggests that structural improvement in LVOT gradients strongly correlates with functional symptom relief in this cohort. This alignment between echocardiographic measures and patient-reported status supports the drug’s role in managing chronic oHCM progression.

Regulatory and Safety Context

Camzyos is approved in more than 60 countries and regions. In the U.S., it is indicated for adults with symptomatic NYHA class II-III oHCM. Due to the risk of heart failure due to systolic dysfunction, the drug is available only through the Camzyos REMS Program. Prescribers must be certified, and patients must undergo regular echocardiogram assessments to monitor LVEF.

Cristian Massacesi, MD, executive vice president and chief medical officer at Bristol Myers Squibb, stated that the long-term and real-world evidence provides greater confidence in treatment decisions for patients living with oHCM.

Bristol Myers Squibb has terminated its partnership with Cellares. The company stated the Cell Shuttle system could not meet necessary requirements to make Breyanzi commercially viable.

Partnership Termination

A spokesperson for Bristol Myers Squibb confirmed the end of the collaboration. The decision stems from technical limitations identified in the partnered technology.

The Cell Shuttle system, developed in conjunction with Cellares, failed to satisfy the operational standards required for the commercialization of Breyanzi. This outcome halts the specific technological integration planned for the cell therapy product.