Phase 3 data show significant reduction in LVOT gradient and a favorable safety profile, positioning Camzyos as a potential first targeted therapy for adolescents with oHCM
Bristol Myers Squibb has reported encouraging results from the Phase 3 SCOUT-HCM trial evaluating Camzyos (mavacamten) in adolescents with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), marking a potentially significant milestone in pediatric cardiology. The study successfully met its primary endpoint, demonstrating a clinically meaningful and statistically significant reduction in Valsalva left ventricular outflow tract (LVOT) gradient at Week 28 compared with placebo. These findings highlight the promise of Camzyos as a targeted pharmacological therapy for adolescents suffering from this rare and often life-threatening cardiac condition.
Obstructive hypertrophic cardiomyopathy is characterized by abnormal thickening of the heart muscle, which can impede blood flow and lead to symptoms such as shortness of breath, chest pain, fatigue, and in severe cases, sudden cardiac events. While treatment options exist for adults, there are currently no approved targeted therapies specifically for adolescents. As a result, treatment strategies for younger patients have largely been extrapolated from adult data, leaving a significant unmet medical need in this population.
The SCOUT-HCM trial represents the first study of a cardiac myosin inhibitor (CMI) in adolescents aged 12 to under 18 years with symptomatic oHCM. Camzyos, a first-in-class CMI, works by targeting the underlying pathophysiology of the disease, reducing excessive contractility of the heart muscle and improving cardiac function. The trial enrolled 44 patients with New York Heart Association (NYHA) class II–III symptoms and evaluated the efficacy and safety of Camzyos over a 28-week treatment period.
Results from the study demonstrated a substantial reduction in Valsalva LVOT gradient, with a least-squares mean difference of −48.0 mm Hg compared to placebo (95% confidence interval: −67.7 to −28.3; P < 0.0001). This reduction is considered both clinically meaningful and statistically significant, indicating a notable improvement in cardiac obstruction among patients receiving Camzyos.
In addition to achieving its primary endpoint, the trial also showed meaningful improvements across multiple secondary endpoints. Patients treated with Camzyos experienced reductions in resting and post-exercise LVOT gradients, with least-squares mean differences of −47.0 mm Hg and −41.7 mm Hg, respectively, both demonstrating strong statistical significance. These improvements suggest that the therapy not only reduces obstruction at rest but also enhances cardiac performance during physical activity.
Further benefits were observed in cardiac structure and function. Camzyos treatment led to improvements in maximal left ventricular wall thickness, with a mean reduction of −1.8 mm, as well as enhanced diastolic function, indicated by a reduction in the E/e’ ratio of −3.4. These structural and functional changes are particularly important, as they may translate into long-term clinical benefits and improved quality of life for patients.
The study also evaluated clinical outcomes such as NYHA functional class and mitral valve function. Patients receiving Camzyos showed improvements in symptom severity and functional capacity, reinforcing the drug’s potential to address both the physiological and symptomatic aspects of the disease.
Safety findings from the SCOUT-HCM trial were consistent with the established safety profile of Camzyos observed in adult populations. The incidence of treatment-emergent adverse events (TEAEs) was similar between the Camzyos and placebo groups, with 18 and 17 patients experiencing at least one event, respectively. Treatment-related TEAEs were also comparable, occurring in two patients in the Camzyos group and three in the placebo group.
Importantly, there were no new safety signals identified in the adolescent population. Serious adverse events were reported in two patients in each group, with only one treatment-related serious adverse event occurring in the Camzyos arm. There were no treatment discontinuations due to adverse events, no deaths, and no cases of atrial fibrillation or symptomatic heart failure during the study period.
A key safety outcome was the preservation of left ventricular ejection fraction (LVEF), a measure of the heart’s pumping ability. No patients in the trial experienced an LVEF below 50%, indicating that Camzyos did not adversely affect cardiac function. This is particularly reassuring given the concerns that can arise when modifying cardiac contractility in a younger population.
The results were presented as a late-breaking clinical trial at the American College of Cardiology’s Annual Scientific Session & Expo 2026 and were simultaneously published in a leading peer-reviewed medical journal, underscoring the significance of the findings within the scientific and medical communities.
Experts involved in the study emphasized the importance of these results. Pediatric hypertrophic cardiomyopathy is a rare condition with potentially severe consequences, and the lack of approved therapies has long been a challenge for clinicians. The positive outcomes from SCOUT-HCM suggest that Camzyos could become the first targeted treatment option specifically approved for adolescents with oHCM, representing a major advancement in care.
From a clinical perspective, the ability to directly address the underlying mechanism of the disease rather than simply managing symptoms could transform the treatment paradigm. For patients and their families, this could mean improved symptom control, better functional capacity, and potentially reduced risk of serious complications.
Bristol Myers Squibb also highlighted the broader implications of the trial results. The company views Camzyos as a cornerstone of its cardiovascular portfolio and a key innovation in the field of cardiac myosin inhibition. The success of the SCOUT-HCM trial reinforces its leadership in this therapeutic area and supports ongoing efforts to expand the use of Camzyos across different patient populations.
Looking ahead, the SCOUT-HCM study is continuing beyond the initial 28-week analysis period. The ongoing phase will provide additional data on the long-term efficacy and safety of Camzyos, with 56-week results expected to be presented at a future medical conference. These extended findings will be critical in further validating the durability of treatment benefits and supporting potential regulatory submissions.
In summary, the Phase 3 SCOUT-HCM trial has demonstrated that Camzyos delivers significant clinical benefits in adolescents with symptomatic obstructive hypertrophic cardiomyopathy, with a safety profile consistent with adult experience. By achieving meaningful reductions in LVOT gradient and improving multiple measures of cardiac function and patient outcomes, Camzyos shows strong potential to become the first targeted pharmacological therapy for this underserved patient group. If approved, it could mark a transformative step forward in the management of pediatric oHCM, offering new hope to patients, families, and healthcare providers alike.
About the Phase 3 SCOUT-HCM Trial
SCOUT-HCM (NCT06253221) is a Phase 3 randomized, double-blind, placebo-controlled, international trial that enrolled 44 adolescent patients (12 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 crossed over to Camzyos), and an open-label long-term extension period for up to 144 weeks.
The primary endpoint is change from baseline to Week 28 in Valsalva LVOT gradient. Secondary endpoints include efficacy parameters of resting and post-exercise LVOT gradients, peak oxygen consumption, symptoms and health status, plus safety and pharmacokinetic parameters.
Joseph Rossano, MD, is a paid consultant to Bristol Myers Squibb and served as the site principal investigator for the SCOUT-HCM study at Children’s Hospital of Philadelphia.
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.
This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 regarding, among other things, the research, development and commercialization of pharmaceutical products. All statements that are not statements of historical facts are, or may be deemed to be, forward-looking statements. Such forward-looking statements are based on current expectations and projections about our future financial results, goals, plans and objectives and involve inherent risks, assumptions and uncertainties, including internal or external factors that could delay, divert or change any of them in the next several years, that are difficult to predict, may be beyond our control and could cause our future financial results, goals, plans and objectives to differ materially from those expressed in, or implied by, the statements. These risks, assumptions, uncertainties and other factors include, among others, that future study results may not be consistent with the results to date, that Camzyos (mavacamten) may not receive regulatory approval for any additional indication described in or suggested by this release in the currently anticipated timeline or at all, any marketing approvals, if granted, may have significant limitations on their use, and, if approved, whether Camzyos for such indication will be commercially successful. No forward-looking statement can be guaranteed. Forward-looking statements in this press release should be evaluated together with the many risks and uncertainties that affect Bristol Myers Squibb’s business and market, particularly those identified in the cautionary statement and risk factors discussion in Bristol Myers Squibb’s Annual Report on Form 10-K for the year ended December 31, 2025, as updated by our subsequent Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other filings with the Securities and Exchange Commission. The forward-looking statements included in this document are made only as of the date of this document and except as otherwise required by applicable law, Bristol Myers Squibb undertakes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events, changed circumstances or otherwise.
