Bristol Myers Squibb Reports Positive Phase 3 SCOUT-HCM Results for Camzyos in Adolescents with Symptomatic oHCM
Bristol Myers Squibb has announced compelling results from its pivotal Phase 3 SCOUT-HCM clinical trial, highlighting the potential of Camzyos (mavacamten) as a transformative therapy for adolescents living with symptomatic obstructive hypertrophic cardiomyopathy (oHCM). The findings mark a significant milestone in pediatric cardiology, as this is the first large-scale study evaluating a cardiac myosin inhibitor (CMI) in patients aged 12 to under 18 years with this rare and potentially life-threatening heart condition.
The late-breaking results were presented at the prestigious American College of Cardiology Annual Scientific Session and Expo 2026 and simultaneously published in The New England Journal of Medicine, underscoring the importance of the data within the global cardiovascular research community.
Addressing a Critical Gap in Pediatric Cardiovascular Care
Obstructive hypertrophic cardiomyopathy (oHCM) is a genetic cardiac disorder characterized by abnormal thickening of the heart muscle, particularly the left ventricle. This thickening can obstruct blood flow out of the heart, leading to a range of symptoms including shortness of breath, chest pain, fatigue, dizziness, and in severe cases, sudden cardiac death.
While advances in the treatment of adult oHCM have accelerated in recent years, pediatric patients have historically faced limited therapeutic options. Current pharmacological approaches for adolescents are largely extrapolated from adult data, with no therapies specifically approved for this younger population. This gap has created an urgent need for targeted treatments that address the unique physiological and developmental considerations of pediatric patients.
The SCOUT-HCM trial was designed to address this unmet need by evaluating the efficacy and safety of Camzyos, a first-in-class cardiac myosin inhibitor that directly targets the underlying hypercontractility of the heart muscle—a hallmark of oHCM.
SCOUT-HCM Trial Design and Patient Population
The Phase 3 SCOUT-HCM study enrolled 44 adolescent patients between the ages of 12 and less than 18 years, all of whom had symptomatic oHCM classified as New York Heart Association (NYHA) class II or III. These classifications indicate moderate to marked limitation in physical activity due to cardiac symptoms.
Participants were randomized to receive either Camzyos or placebo over a 28-week treatment period. The trial’s primary objective was to assess the change from baseline in Valsalva left ventricular outflow tract (LVOT) gradient—a key measure of the degree of obstruction in the heart—at Week 28.
Secondary endpoints included a range of functional, structural, and clinical measures, such as resting and post-exercise LVOT gradients, diastolic function, left ventricular wall thickness, mitral valve function, and NYHA functional class.
Primary Endpoint Achievement: Significant Reduction in LVOT Gradient
The SCOUT-HCM trial successfully met its primary endpoint, demonstrating a statistically significant and clinically meaningful reduction in Valsalva LVOT gradient in patients treated with Camzyos compared with placebo at Week 28.
The least-squares mean difference between the treatment and placebo groups was −48.0 mm Hg (95% confidence interval: −67.7 to −28.3), with a highly significant p-value of less than 0.0001. This magnitude of reduction reflects a substantial alleviation of the obstruction that impairs blood flow from the heart, which is central to the disease’s pathology.
Importantly, reductions in LVOT gradient are closely associated with improvements in symptoms and overall cardiac function, suggesting that Camzyos may offer meaningful clinical benefits beyond hemodynamic changes.
Robust Improvements Across Secondary Endpoints
In addition to achieving its primary endpoint, Camzyos demonstrated consistent and clinically relevant improvements across multiple secondary endpoints, further reinforcing its therapeutic potential.
Resting and Post-Exercise LVOT Gradients
Patients receiving Camzyos experienced significant reductions in both resting and post-exercise LVOT gradients compared to placebo:
- Resting LVOT gradient: LS mean difference of −47.0 mm Hg (95% CI: −62.7 to −31.4; nominal p < 0.0001)
- Post-exercise LVOT gradient: LS mean difference of −41.7 mm Hg (95% CI: −59.7 to −23.7; nominal p < 0.0001)
These findings indicate that the drug effectively reduces obstruction both at rest and during physical activity, which is particularly important for improving exercise tolerance and daily functioning in adolescents.
Achievement of Clinically Meaningful Thresholds
A key supportive measure of efficacy was the proportion of patients achieving a maximal LVOT gradient of less than 30 mm Hg—a threshold often associated with reduced symptom burden and improved outcomes. A significantly greater proportion of patients in the Camzyos group reached this target compared to those receiving placebo.
Structural and Functional Cardiac Improvements
Beyond hemodynamic benefits, Camzyos also demonstrated favorable effects on cardiac structure and function, addressing the underlying disease process.
Reduction in Left Ventricular Wall Thickness
Treatment with Camzyos led to a statistically significant reduction in maximal left ventricular wall thickness, with an LS mean difference of −1.8 mm (95% CI: −3.4 to −0.2; nominal p = 0.0269). This finding suggests a reversal, or at least attenuation, of the pathological hypertrophy that characterizes oHCM.
Improvement in Diastolic Function
Camzyos also improved diastolic function, as measured by the E/e’ ratio—a key echocardiographic parameter that reflects the heart’s ability to relax and fill properly. The LS mean difference was −3.4 (95% CI: −5.1 to −1.6; nominal p = 0.0002), indicating enhanced ventricular relaxation and reduced filling pressures.
Mitral Valve Function and NYHA Class
Additional benefits were observed in mitral valve function and NYHA functional class, suggesting that patients experienced not only objective improvements in cardiac parameters but also subjective improvements in symptoms and quality of life.
Safety and Tolerability Profile
The safety profile of Camzyos in the SCOUT-HCM trial was consistent with that observed in adult populations, with no new safety signals identified.
Key safety findings include:
- Treatment-emergent adverse events (TEAEs): Reported in 18 patients receiving Camzyos and 17 receiving placebo
- Treatment-related TEAEs: Observed in 2 patients in the Camzyos group versus 3 in the placebo group
- Treatment-emergent serious adverse events (TESAEs): Reported in 2 patients in each group
- Treatment-related TESAEs: Observed in 1 patient receiving Camzyos and none in the placebo group
Importantly, there were:
- No treatment discontinuations due to adverse events
- No deaths during the study period
- No cases of atrial fibrillation or symptomatic heart failure
- No instances of left ventricular ejection fraction (LVEF) dropping below 50%
These findings indicate that Camzyos was well tolerated in the adolescent population, with a safety profile comparable to placebo and consistent with prior adult studies.
Expert Perspectives and Clinical Significance
Clinical experts have emphasized the importance of these findings in advancing the treatment landscape for pediatric oHCM. The disease, though rare, carries significant risks and can profoundly impact quality of life for young patients and their families.
The SCOUT-HCM trial represents the first robust, randomized evidence supporting the use of a targeted therapy specifically in adolescents. By directly modulating cardiac myosin activity, Camzyos addresses the fundamental mechanism driving the disease, rather than merely alleviating symptoms.
This mechanism-based approach aligns with broader trends in precision medicine and highlights the potential for disease-modifying therapies in cardiology.
Bristol Myers Squibb’s Strategic Vision
For Bristol Myers Squibb, the SCOUT-HCM results reinforce its leadership in the emerging field of cardiac myosin inhibition. Camzyos has already established a strong presence in the adult oHCM market, and these new data extend its potential into the pediatric setting.
The company has emphasized its commitment to reshaping the understanding and management of oHCM, from diagnosis to long-term treatment. By expanding the therapeutic reach of Camzyos, Bristol Myers Squibb aims to address the needs of a broader patient population, including those who have historically been underserved.
Next Steps and Future Outlook
The SCOUT-HCM study is ongoing, with the 28-week active treatment period completed and longer-term data expected. Bristol Myers Squibb plans to collaborate with investigators to present 56-week results at an upcoming medical congress, which will provide additional insights into the durability of treatment effects and long-term safety.
The company is also expected to engage with regulatory authorities, including the U.S. Food and Drug Administration (FDA), to discuss potential pathways for approval in the adolescent population. If approved, Camzyos could become the first therapy specifically indicated for pediatric patients with oHCM, representing a major advancement in the field.
The Phase 3 SCOUT-HCM trial marks a pivotal moment in the evolution of treatment for obstructive hypertrophic cardiomyopathy in adolescents. With statistically significant reductions in LVOT gradient, meaningful improvements across multiple secondary endpoints, and a favorable safety profile, Camzyos has demonstrated strong potential as a first-in-class therapy for this vulnerable patient population.
As Bristol Myers Squibb advances its regulatory and clinical development efforts, the cardiology community will be watching closely. The possibility of introducing a targeted, disease-modifying therapy for adolescents with oHCM represents not only a scientific breakthrough but also a meaningful step forward in improving the lives of patients and families affected by this challenging condition.
About Obstructive Hypertrophic Cardiomyopathy (oHCM) in Adolescent Patients
Hypertrophic cardiomyopathy (HCM) is a primary cardiac disorder that may result from known or suspected genetic defects in sarcomeric proteins of the cardiac myocyte or be due to unknown reasons (idiopathic). Adolescents with obstructive HCM suffer substantial morbidity largely related to reduced exertional tolerance. Though available treatments can lead to improvement in symptoms, they have significant limitations for adolescent patients (e.g., side effects from beta-blockers and risks of invasive procedures).
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. In the U.S., CAMZYOS is indicated for the treatment of adults with symptomatic New York Heart Association (NYHA) class II-III obstructive hypertrophic cardiomyopathy (oHCM) to improve functional capacity and symptoms. 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 translate to improvements in symptoms for patients 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.
CAMZYOS is supported by the largest body of worldwide evidence in the CMI treatment class, with up to five years of follow up across multiple long-term evidence and real-world studies, demonstrating the consistent and sustained benefits of CAMZYOS to improve symptoms and impact cardiac structure. CAMZYOS has been prescribed by more than 4,500 healthcare providers (HCPs) to more than 22,000 patients in the U.S. alone.
Bristol Myers Squibb: Changing the Course of Cardiovascular Disease
Bristol Myers Squibb is inspired by a single vision – transforming patients’ lives through science. Cardiovascular disease is the leading cause of death worldwide, and despite major advances in how we prevent and treat it, the human and societal burden continues to worsen each year. Whether a cardiovascular disease that affects millions of people around the world, or a rarer condition, the need is the same: new and better treatment options that allow people to continue to live their fullest lives.
Bristol Myers Squibb is committed to developing new treatments to address the global burden of cardiovascular disease. Building on our 70-year legacy of discovering and delivering paradigm-changing cardiovascular medicines, we are leveraging our experience and expertise to take cardiovascular research to the next level and deliver meaningful, life‑changing outcomes for patients.
Source Link:https://www.businesswire.com/
