Mavacamten Benefits Hold Through 56 Weeks in Adolescents With oHCM

Reductions in left ventricular outflow tract (LVOT) obstruction with mavacamten (Camzyos; Bristol Myers Squibb) were maintained through 56 weeks in adolescents with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), with no new safety signals, according to phase 3 SCOUT-HCM (NCT06253221) results presented by Bristol Myers Squibb.¹

“These results are significant as they build upon the understanding of the meaningful impact of Camzyos in pediatric patients with symptomatic oHCM, evaluated in a 56-week study that included a 28-week placebo-controlled period,” Cordula Wolf, MD, associate professor, Technical University of Munich University Hospital German Heart Centre, said in a statement. This is the first time a cardiac myosin inhibitor has been evaluated in this patient population for this length of time and in a double-blind study. These results serve as an important resource for healthcare providers and patients when discussing their care plan and the potential of Camzyos, the first approved treatment option for pediatric patients in the US with symptomatic oHCM.”

The late-breaking data, shared at the Hypertrophic Cardiomyopathy Medical Society (HCMS) Scientific Sessions in Chicago, Illinois, follow the FDA's September 2026 approval of mavacamten for pediatric patients weighing 30 kg (66 lb) or more, which was based on 28-week results from the same trial.² The cardiac myosin inhibitor (CMI) was first approved in 2022 for adults with symptomatic NYHA class II-III oHCM and, according to the company, is now the only FDA-approved therapy for oHCM in a pediatric population.³

Gradient Reductions Sustained in Both Treatment Arms

SCOUT-HCM randomly assigned 44 patients aged 12 to younger than 18 years with symptomatic oHCM to mavacamten or placebo for a 28-week double-blind period.¹ Of those, 43 (mavacamten, n = 23; placebo, n = 20) completed the placebo-controlled period, after which all received mavacamten through week 56. At baseline, most patients were taking beta blockers (83% in the mavacamten group and 86% in the placebo group), and mean Valsalva LVOT gradients were 78 mm Hg and 81 mm Hg, respectively.

Patients who received mavacamten for the full 56 weeks had a mean change from baseline in Valsalva LVOT gradient of −48.1 mm Hg. Patients who switched from placebo to mavacamten at week 28 achieved a similar degree of gradient reduction, and both arms showed meaningful improvements in several secondary end points, according to the company. The release did not report values for those secondary end points.

The 56-week findings track closely with the primary 28-week analysis, in which mean Valsalva LVOT gradient changed by −49.4 mm Hg with mavacamten vs −1.8 mm Hg with placebo (least-squares mean difference, −48.0 mm Hg; 95% CI, −67.7 to −28.3; P < .001).²

No LVEF Declines Below 50% Through 56 Weeks

Safety findings were consistent with earlier SCOUT-HCM results and with phase 3 studies of mavacamten in adults.¹ In the mavacamten-mavacamten arm, 5 treatment-related treatment-emergent adverse events (TEAEs) and 2 serious TEAEs were reported over 56 weeks; the placebo-mavacamten arm had 1 and 0, respectively, over its 28 weeks of active treatment. No patient in the trial had a left ventricular ejection fraction (LVEF) below 50% at any point during the 56 weeks.

The LVEF finding matters for day-to-day management: mavacamten carries a boxed warning for heart failure due to systolic dysfunction, requires echocardiographic LVEF assessments before and during treatment, and should be interrupted if LVEF falls below 50% at any visit.² It remains available only through a restricted Risk Evaluation and Mitigation Strategy (REMS) program.³

SCOUT-HCM includes up to 200 weeks of treatment, with the 28-week placebo-controlled and 28-week active-treatment periods followed by an open-label extension of up to 144 weeks.¹ Bristol Myers Squibb is also presenting adult data at the American Heart Association's Scientific Sessions 2026, including 4-year findings from the Camzyos REMS Program that showed safety consistent with clinical trials and a cardiac magnetic resonance analysis of the MAVA-LTE study showing favorable changes in cardiac structure and function over up to 5 years.

“Symptomatic oHCM is a serious condition for which having effective and safe treatments is crucial. These additional SCOUT-HCM results provide added confidence in Camzyos to health care providers as they consider treatment options for their pediatric patients with oHCM,” said Cristian Massacesi, MD, executive vice president, chief medical officer, and head of development, Bristol Myers Squibb, in a statement. “BMS is committed to researching and developing new treatments to address cardiovascular disease. The data presented at these congresses helps us better understand symptomatic oHCM and the role of Camzyos in delivering more meaningful outcomes for patients and their families.”

References

1. Bristol Myers Squibb presents 56-week phase 3 data in pediatric patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM) for Camzyos (mavacamten) at the Hypertrophic Cardiomyopathy Medical Society (HCMS) Scientific Sessions. News release. Bristol Myers Squibb. November 6, 2026. Accessed November 9, 2026. https://news.bms.com/news/details/2026/Bristol-Myers-Squibb-Presents-56-Week-Phase-3-Data-in-Pediatric-Patients-with-Symptomatic-Obstructive-Hypertrophic-Cardiomyopathy-oHCM-for-Camzyos-mavacamten-at-the-Hypertrophic-Cardiomyopathy-Medical-Society-HCMS-Scientific-Sessions/default.aspx
2. The U.S. Food and Drug Administration approves expanded indication for Bristol Myers Squibb's Camzyos (mavacamten) for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (oHCM) in adults and pediatric patients. News release. Bristol Myers Squibb. September 30, 2026. Accessed November 9, 2026. https://news.bms.com/news/corporate-financial/2026/U-S--Food-and-Drug-Administration-Approves-Expanded-Indication-for-Bristol-Myers-Squibbs-CAMZYOS-mavacamten-for-the-Treatment-of-Symptomatic-Obstructive-Hypertrophic-Cardiomyopathy-oHCM-in-Adults-and-Pediatric-Patients/default.aspx
3. Steinzor P. FDA expands mavacamten label to include children with oHCM. AJMC^®. October 1, 2026. Accessed November 9, 2026. https://www.ajmc.com/view/fda-expands-mavacamten-label-to-include-children-with-ohcm