Bristol Myers Squibb Presents 56-Week SCOUT-HCM Results Supporting Camzyos in Pediatric Patients With Obstructive Hypertrophic Cardiomyopathy
Bristol Myers Squibb has announced positive 56-week results from the Phase 3 SCOUT-HCM clinical trial evaluating Camzyos (mavacamten) in pediatric patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM). The updated findings were presented in a late-breaking session at the Hypertrophic Cardiomyopathy Medical Society (HCMS) Scientific Sessions on November 6, 2026, in Chicago, Illinois. The results provide additional evidence supporting the efficacy and safety of Camzyos in patients aged 12 to younger than 18 years with this serious cardiovascular condition.
The 56-week findings are consistent with the previously reported 28-week results from SCOUT-HCM and demonstrate sustained reductions in left ventricular outflow tract (LVOT) gradients among patients receiving mavacamten. Patients who initially received placebo and subsequently switched to active treatment also achieved a similar degree of gradient reduction during the study’s treatment period. Both groups demonstrated meaningful improvements across several secondary endpoints, with no new safety signals reported.
These findings add to the clinical evidence supporting Camzyos, which Bristol Myers Squibb describes as having the broadest indication of any cardiac myosin inhibitor (CMI). It is also the first cardiac myosin inhibitor approved for pediatric patients with symptomatic oHCM in the United States.
The company is presenting additional clinical and real-world evidence at the American Heart Association’s (AHA) Scientific Sessions 2026, taking place November 6–9, 2026, in Chicago. These presentations include analyses of long-term safety, cardiac structure and function, cardiovascular risk and real-world treatment outcomes in adults with symptomatic oHCM. Together, the findings are intended to provide healthcare professionals with a broader understanding of the use of mavacamten across different patient populations and treatment settings.
SCOUT-HCM Evaluates Mavacamten in Pediatric oHCM
SCOUT-HCM is a randomized, double-blind, placebo-controlled Phase 3 clinical trial designed to evaluate the efficacy and safety of Camzyos compared with placebo in pediatric patients aged 12 to younger than 18 years who have symptomatic obstructive hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is a condition in which the heart muscle becomes abnormally thick, potentially making it more difficult for the heart to pump blood effectively. In obstructive hypertrophic cardiomyopathy, thickening of the heart muscle can interfere with blood flow from the left ventricle into the aorta. This obstruction can contribute to symptoms and limitations in physical activity.
For pediatric patients with symptomatic oHCM, treatment decisions require careful consideration of disease severity, symptoms, cardiac function and the potential risks associated with therapy. The availability of a treatment specifically approved for eligible pediatric patients represents an important development in addressing the needs of this population.
Camzyos is a cardiac myosin inhibitor designed to target the underlying mechanisms involved in excessive cardiac muscle contraction. By modulating cardiac myosin activity, mavacamten is intended to reduce excessive contraction and improve the hemodynamic effects associated with left ventricular outflow tract obstruction.
The SCOUT-HCM study was designed to assess whether this treatment approach could provide clinical benefits in adolescents with symptomatic oHCM. The trial included an initial 28-week double-blind, placebo-controlled period, followed by an active treatment period extending through Week 56.
A total of 44 participants were randomized in the study. Of these, 43 patients completed the double-blind placebo-controlled period and entered the active treatment period. The treatment groups included 23 patients initially assigned to mavacamten and 20 patients initially assigned to placebo.
At Week 28, all 43 participants who completed the initial study period were assigned to receive Camzyos through Week 56. This allowed investigators to evaluate the longer-term effects of treatment in patients who had initially received mavacamten as well as those who transitioned from placebo to active therapy.
Sustained Reductions in Left Ventricular Outflow Tract Gradient
The 56-week results demonstrated significant reductions in Valsalva left ventricular outflow tract gradients among patients in both study groups following treatment with mavacamten.
Patients initially assigned to mavacamten who continued treatment through Week 56 experienced a mean change from baseline of -48.1 mmHg in the Valsalva LVOT gradient after 56 weeks of treatment.
Patients who initially received placebo and subsequently switched to mavacamten also experienced a similar degree of LVOT gradient reduction after beginning active treatment.
The Valsalva LVOT gradient is an important measure in obstructive hypertrophic cardiomyopathy. It assesses the pressure difference across the left ventricular outflow tract during the Valsalva maneuver, which can help reveal the degree of obstruction affecting blood flow from the heart.
Reducing this gradient is an important treatment objective because elevated LVOT gradients are associated with the mechanical obstruction characteristic of oHCM. The sustained reduction observed in patients receiving mavacamten through Week 56 provides additional evidence of the treatment’s pharmacological activity in pediatric patients.
The results also demonstrate that patients who transitioned from placebo to mavacamten experienced improvements after beginning active treatment. This provides further information about the response to therapy across both original randomization groups.
In addition to the improvements in LVOT gradient, patients in both study arms demonstrated meaningful improvements in several secondary endpoints. These findings suggest that the observed effects extended beyond the primary hemodynamic measure evaluated in the study.
The company reported that the 56-week results were consistent with the previously announced 28-week findings, supporting the continued evaluation of mavacamten as a treatment option for adolescents with symptomatic obstructive hypertrophic cardiomyopathy.
Safety Profile Remained Consistent Through Week 56
Bristol Myers Squibb also reported safety findings from the extended treatment period. The safety profile of Camzyos in SCOUT-HCM remained consistent with previously reported trial results and with findings from Phase 3 studies evaluating mavacamten in adults.
Treatment-related treatment-emergent adverse events (TEAEs) and serious TEAEs were reported at low levels in the study.
In the group initially assigned to mavacamten and subsequently continuing mavacamten treatment, five treatment-related TEAEs and two serious TEAEs were reported over 56 weeks of treatment.
In the group initially assigned to placebo and subsequently receiving mavacamten, one treatment-related TEAE and no serious TEAEs were reported over the initial 28-week placebo-controlled treatment period, as described in the reported results.
An important safety observation was that no patient in the trial experienced a left ventricular ejection fraction (LVEF) below 50% during the 56-week period.
LVEF measures the percentage of blood pumped out of the left ventricle with each heartbeat and is an important indicator of cardiac pumping function. Monitoring LVEF is particularly relevant during treatment with cardiac myosin inhibitors because changes in cardiac contractility may affect ventricular function.
The absence of reported LVEF measurements below 50% during the study period provides additional safety information for the pediatric population evaluated in SCOUT-HCM.
Overall, the company reported no new safety signals during the extended treatment period. These findings add to the available understanding of mavacamten’s safety profile in adolescents, although continued monitoring and additional clinical experience remain important as treatment use expands.
Clinical Experts Highlight the Importance of Pediatric Data
Cordula Wolf, M.D., associate professor at the Technical University of Munich (TUM) University Hospital German Heart Centre, highlighted the significance of the updated SCOUT-HCM findings.
Dr. Wolf noted that the 56-week study provides additional information about the potential impact of Camzyos in pediatric patients with symptomatic oHCM. She emphasized that this is the first time a cardiac myosin inhibitor has been evaluated in this patient population over this length of time in a double-blind study that included a 28-week placebo-controlled period.
According to Dr. Wolf, the findings represent an important resource for healthcare providers and patients when discussing treatment plans and considering the potential benefits of Camzyos.
The extended follow-up is particularly relevant because pediatric patients with symptomatic oHCM have historically had fewer treatment options specifically evaluated in their age group. Clinical evidence from a controlled study can help inform discussions about treatment selection, expected outcomes and safety monitoring.
Dr. Wolf also highlighted the importance of Camzyos as the first approved treatment option in the United States for pediatric patients with symptomatic oHCM.
Cristian Massacesi, M.D., executive vice president, chief medical officer and head of Development at Bristol Myers Squibb, said symptomatic oHCM is a serious condition for which effective and safe treatment options are important.
Dr. Massacesi noted that the additional SCOUT-HCM results provide further confidence in Camzyos as healthcare professionals consider treatment options for pediatric patients. He also emphasized the company’s continued commitment to researching and developing treatments for cardiovascular diseases.
According to Dr. Massacesi, clinical and real-world evidence presented at the scientific meetings will contribute to a better understanding of symptomatic oHCM and the potential role of Camzyos in improving outcomes for patients and their families.
Additional Evidence to Be Presented at AHA Scientific Sessions 2026
Beyond the pediatric SCOUT-HCM results, Bristol Myers Squibb is presenting additional clinical and real-world analyses at the American Heart Association’s Scientific Sessions 2026.
These presentations expand the evidence base supporting Camzyos in adults with symptomatic obstructive hypertrophic cardiomyopathy. Several analyses focus on long-term treatment experience, cardiac structure and function, cardiovascular risk assessment and outcomes across patient subgroups.
One presentation reports safety findings from the Camzyos Risk Evaluation and Mitigation Strategy (REMS) program after four years of follow-up. The analysis showed safety findings consistent with those observed in clinical trials.
The REMS program is designed to support the safe use of Camzyos through risk-management measures and appropriate monitoring. Longer-term information from the program provides additional insight into the treatment’s safety profile outside the controlled environment of individual clinical trials.
The four-year follow-up findings are relevant because long-term safety is an important consideration for patients with chronic cardiovascular conditions who may require ongoing treatment. Consistency between the REMS safety findings and clinical trial observations adds to the available evidence regarding the use of mavacamten in routine clinical practice.
Cardiac Magnetic Resonance Analysis Shows Favorable Changes
Another presentation at the AHA meeting will report findings from a cardiac magnetic resonance (CMR) analysis of the EXPLORER cohort in the MAVA-LTE study.
The analysis evaluated changes in measures of cardiac structure and function among patients receiving Camzyos over follow-up periods of up to five years.
According to Bristol Myers Squibb, favorable changes were observed across the assessed measures of cardiac structure and function.
CMR is an imaging technique that provides detailed information about the heart’s anatomy, tissue characteristics and function. In patients with hypertrophic cardiomyopathy, this type of assessment can help researchers examine changes in cardiac structure over time.
The findings from the MAVA-LTE analysis provide additional long-term information about the effects of mavacamten beyond changes in LVOT gradients and clinical symptoms. They also contribute to a broader understanding of how treatment may influence cardiac measurements during extended follow-up.
Proteomic Analysis Evaluates Cardiovascular Risk
Bristol Myers Squibb will also present an analysis from the EXPLORER-HCM study examining the impact of Camzyos treatment on a proteomic cardiovascular risk score.
The analysis evaluated the CV Risk SomaSignal® Test (SST) score in adults with symptomatic oHCM. This score has previously been reported to predict cardiovascular risk over a four-year period.
According to the company, treatment with Camzyos reduced the CV Risk SST score among adult patients included in the analysis.
Proteomic testing examines patterns of proteins and their associated biological signals to provide information about disease processes and potential health risks. In this analysis, the risk score was used to evaluate cardiovascular risk-related changes in patients receiving mavacamten.
The findings offer an additional perspective on the potential effects of treatment, complementing traditional assessments of symptoms, cardiac function and hemodynamic measurements.
However, a change in a proteomic risk score should be interpreted in the context of the specific analysis and does not independently establish a reduction in clinical cardiovascular events. Further research may help clarify how these biomarker findings relate to long-term patient outcomes.
MARVEL-HCM Provides Real-World Insights Across Genetic Subgroups
An additional analysis from the MARVEL-HCM study will provide real-world evidence on Camzyos use among patients categorized according to sarcomere gene variant status.
The analysis examined treatment effectiveness and safety in patients who were sarcomere gene variant-positive and those who were variant-negative.
Bristol Myers Squibb reported that effectiveness and safety results were consistent across both subgroups.
Sarcomere gene variants can be associated with the development of hypertrophic cardiomyopathy. Evaluating treatment outcomes according to genetic status may help researchers and healthcare professionals better understand whether treatment responses differ among patients with distinct genetic characteristics.
The MARVEL-HCM findings provide real-world information that complements data generated in controlled clinical trials. Consistency across the variant-positive and variant-negative groups suggests that the observed treatment outcomes were not limited to one of these genetic subgroups in the analysis.
Together with the long-term REMS, MAVA-LTE and EXPLORER-HCM findings, the MARVEL-HCM results add to the growing body of clinical and real-world evidence supporting the use of Camzyos in adult patients with symptomatic oHCM.
FDA Approval Expanded Camzyos Use to Pediatric Patients
The U.S. Food and Drug Administration (FDA) approved Camzyos in September 2026 for the treatment of pediatric patients weighing at least 30 kilograms (66 pounds) with symptomatic obstructive hypertrophic cardiomyopathy. The approval covers the use of the medicine to improve functional capacity and symptoms.
The FDA decision was based on positive 28-week results from the Phase 3 SCOUT-HCM clinical trial.
The pediatric approval represents an expansion of the medicine’s previously established use in adults. Camzyos was first approved by the FDA in 2022 for adults with symptomatic New York Heart Association (NYHA) class II–III obstructive hypertrophic cardiomyopathy.
The September 2026 decision made Camzyos the first cardiac myosin inhibitor approved for pediatric patients with symptomatic oHCM in the United States.
The new 56-week findings provide additional follow-up information beyond the 28-week results that supported the pediatric approval. Sustained reductions in LVOT gradients, improvements in secondary endpoints and the absence of new safety signals contribute to the growing clinical evidence available for the medicine in adolescents.
Bristol Myers Squibb states that Camzyos is supported by the largest body of worldwide evidence within the cardiac myosin inhibitor treatment class.
Continued Development and Evidence Generation
The SCOUT-HCM results and additional AHA presentations reflect Bristol Myers Squibb’s continued efforts to evaluate Camzyos across different patient populations and clinical settings.
The pediatric findings provide extended information about treatment response and safety in adolescents with symptomatic oHCM, while the adult analyses examine long-term outcomes, cardiac imaging measurements, proteomic risk assessments and real-world effectiveness across genetic subgroups.
For pediatric patients, the 56-week SCOUT-HCM results demonstrate that reductions in Valsalva LVOT gradients were maintained among those continuing mavacamten treatment. Patients who transitioned from placebo to active treatment also achieved similar reductions after starting Camzyos. The reported safety findings remained consistent with earlier results, and no patient experienced an LVEF below 50% during the 56-week period.
For adults, the additional evidence presented at the AHA Scientific Sessions provides further insight into the treatment’s long-term safety and potential effects on cardiac structure, function and cardiovascular risk-related measures.
Overall, the updated SCOUT-HCM findings strengthen the clinical evidence supporting Camzyos in pediatric patients with symptomatic obstructive hypertrophic cardiomyopathy. The results also reinforce Bristol Myers Squibb’s broader effort to expand the understanding of cardiac myosin inhibition and its role in managing this condition. As additional long-term and real-world data become available, healthcare professionals will have more information to guide treatment discussions and evaluate outcomes for patients living with oHCM.
About the Phase 3 SCOUT-HCM Trial1,2,3
SCOUT-HCM (NCT06253221) is a Phase 3 randomized, double-blind, placebo-controlled, international trial that enrolled 44 pediatric patients (12 years to <18 years old) with symptomatic oHCM. The trial includes three treatment periods totaling up to 200 weeks: a 28-week placebo-controlled period, followed by a 28-week active-treatment period (when patients randomized to placebo cross over to Camzyos), and an open-label long-term extension period for up to 144 weeks. At baseline, 83% and 86% of patients were receiving beta blockers, 13% and 10% were receiving calcium channel blockers, and 17% and 24% were receiving disopyramide, in the Camzyos and placebo groups, respectively.
Mean LVEF was 69.0% in the Camzyos group and 67.4% in the placebo group; mean Valsalva LVOT gradient was 78 mmHg in the Camzyos group and 81 mmHg in the placebo group. Patients were randomized in a 1:1 ratio and administered either Camzyos, starting dose of 2.5 mg Camzyos for body weight 35 to <45 kg, 5 mg Camzyos for body weight ≥45 kg, or placebo, once daily for 28 weeks. Dose adjustment was based on clinical echocardiogram parameters.
The primary endpoint was change from baseline to Week 28 in Valsalva LVOT gradient (mmHg). Secondary endpoints (descriptive only) included change from baseline to Week 28 in efficacy parameters of resting and postexercise LVOT gradients, peak oxygen consumption (proportion of patients achieving an increase from baseline in pVO2), symptoms (proportion of patients with at least 1 NYHA Class improvement) and HCM Symptom Questionnaire Shortness of Breath domain (HCMSQ SoB), plus safety and pharmacokinetic parameters.
About CAMZYOS® (mavacamten)
CAMZYOS® (mavacamten) is the most extensively studied cardiac myosin inhibitor (CMI), approved by regulatory bodies in more than 60 countries and regions across five continents worldwide. CAMZYOS is supported by the largest body of worldwide evidence in the CMI treatment class, with approvals resulting from several phase III clinical trials (EXPLORER-HCM, VALOR-HCM, SCOUT-HCM, as well as HORIZON-HCM in Japan and EXPLORER-CN in China), and up to five years of follow up in multiple pivotal trial long-term extensions (EXPLORER-LTE, VALOR-HCM LTE), providing additional data on the consistent and sustained results for CAMZYOS to improve symptoms and impact cardiac structure and function.
In the U.S., CAMZYOS is indicated for the treatment of symptomatic oHCM to improve functional capacity and symptoms in adults and pediatric patients weighing 30 kg (66 lbs) or more. In the European Union, CAMZYOS is indicated for the treatment of symptomatic (NYHA, class II-III) oHCM in adult patients.
A selective, reversible, allosteric inhibitor of cardiac myosin, CAMZYOS targets hypercontractility, the source of oHCM. Reduction in cardiac contractility with CAMZYOS treatment leads to reduced LVOT obstruction, improved energy consumption, and lower cardiac filling pressures in oHCM patients. These effects have translated to demonstrated symptom improvements in clinical studies for adults with symptomatic oHCM, enabling them to be more active in their daily lives. CAMZYOS can be used with or without background therapies, including for newly diagnosed patients.