Bristol Myers Squibb Showcases Landmark Real-World Data on Camzyos in Obstructive Hypertrophic Cardiomyopathy at ESC Congress 2025
Bristol Myers Squibb (NYSE: BMY) unveiled new results from its global COLLIGO-HCM study at the European Society of Cardiology (ESC) Congress 2025 in Madrid, Spain. The study, presented during an oral session, represents one of the most comprehensive real-world evaluations to date of Camzyos® (mavacamten), the first and only approved cardiac myosin inhibitor, in patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM).
The data demonstrated that treatment with Camzyos was associated with meaningful reductions in left ventricular outflow tract (LVOT) obstruction and sustained improvements in symptom burden across a racially and geographically diverse population. Importantly, the outcomes align with those previously reported in randomized controlled clinical trials, reinforcing Camzyos as a global standard of care for patients with New York Heart Association (NYHA) class II–III symptomatic oHCM.
Understanding the Burden of Obstructive HCM
Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease, affecting approximately one in 500 individuals worldwide. In its obstructive form, the condition is characterized by abnormal thickening of the heart muscle, leading to LVOT obstruction, reduced cardiac output, and a broad spectrum of symptoms, ranging from breathlessness and chest pain to dizziness, syncope, and risk of sudden cardiac death.
Patients with Bristol symptomatic oHCM often experience a significant decline in quality of life. Standard first-line therapies—including beta blockers, calcium channel blockers, or disopyramide—are frequently inadequate to fully control symptoms. Surgical or catheter-based interventions, such as septal myectomy or alcohol septal ablation, may be required, but these procedures carry risks and are not universally accessible.
Camzyos, by directly targeting cardiac myosin, addresses the underlying pathophysiology of HCM by reducing excessive contractility and improving cardiac filling. The therapy represents a major shift in treatment strategy, and its real-world validation has been eagerly awaited by the cardiology community.
The COLLIGO-HCM Study
The COLLIGO-HCM study forms part of the broader WAYFARER-HCM program (Worldwide AnalYsis on eFfectiveness AcRoss divErse populations for Real-world mavacamten use in patients with Hypertrophic CardioMyopathy). Through WAYFARER-HCM, Bristol Myers Squibb is collecting extensive global real-world evidence across seven countries—the United States, Canada, Germany, United Kingdom, Netherlands, Australia, and Israel—with data representing more than 3,000 patients to date.
COLLIGO-HCM Bristol specifically analyzed outcomes from 278 patients with symptomatic oHCM treated across four continents. What distinguishes this study from traditional clinical trials is its ability to capture outcomes in a racially diverse, real-world population, including groups that are often underrepresented in clinical research.
At baseline, 54.7% of patients were classified as NYHA class II, while 45.3% were NYHA class III, underscoring the Bristol significant symptom burden within the study cohort. Importantly, the patient pool included 23.2% Black, 5.4% Asian, and 4.3% Middle Eastern or North African participants, reflecting a truly global representation.
Key Findings
Symptom Improvements
One of the most encouraging findings was the consistent improvement in NYHA functional class:
- 59.9% of patients achieved at least a one-class improvement by week 24.
- By week 12, 86.5% of patients had improved to NYHA class II or below.
- By week 24, this proportion rose to 94.4%, including nearly one-third (30.9%) who improved to NYHA class I, meaning they were essentially asymptomatic.
- Improvements were durable, with benefits sustained through 96 weeks of follow-up.
These findings are particularly meaningful in a condition where symptom burden directly impacts daily functioning, exercise capacity, and psychological well-being.
LVOT Gradient Reduction
Equally important were the results related to hemodynamic improvements:
- By week 36, 90.3% of patients achieved mean resting LVOT gradients of ≤30 mm Hg.
- Under Valsalva provocation, 76.8% of patients also achieved gradients of ≤30 mm Hg.
- These reductions were durable, persisting through week 96.
LVOT gradient reduction is a key Bristol therapeutic goal in oHCM, as it correlates strongly with both symptom relief and improved long-term outcomes.
Background Medication Adjustments
Another notable finding was the reduction in reliance on concomitant therapies:
- 7.2% of patients initiated Camzyos as monotherapy.
- Among those receiving background medications at baseline (n=258), 26.4% discontinued at least one therapy, and 5% down-titrated after starting Camzyos.
This suggests that Camzyos not only provides symptom relief but may also simplify treatment regimens and reduce polypharmacy, an important factor in chronic disease management.
Cardiac Function and Safety
Safety outcomes Bristol were consistent with Camzyos’ established profile:
- Mean left ventricular ejection fraction (LVEF) remained stable at or above 61% throughout follow-up (baseline was 66%).
- Temporary treatment interruption due to LVEF ≤50% occurred in 11 patients (4%).
- Permanent discontinuation for the same reason was rare, affecting just three patients (1.1%). Importantly, all patients recovered to LVEF >50% following discontinuation.
- The incidence of new-onset atrial fibrillation was 2.9% (eight patients), in line with prior clinical trial data.
These results reinforce that Camzyos can be safely administered with careful monitoring, consistent with current regulatory guidelines. Monitoring requirements vary internationally, with a formal Risk Evaluation and Mitigation Strategy (REMS) program in place in the U.S.
Expert Perspectives
Dr. Arnon Adler, Bristol staff cardiologist at the Peter Munk Cardiac Centre (University Health Network, Toronto), and associate professor at the University of Toronto, highlighted the real-world significance of the findings:
“Obstructive HCM can lead to considerable negative impact on patients’ lives. These global real-world outcomes data, which are consistent with results from clinical trials, reinforce the overall effectiveness and safety profile of Camzyos and its benefits for diverse global patient groups, including those that are often underrepresented in clinical trials.”
Dr. Homa Dastani, Vice President, Global HEOR Immunology and Cardiovascular at Bristol Myers Squibb, emphasized the importance of complementing clinical trial evidence with real-world insights:
“Real-world outcomes data have the potential to provide important insights from clinical practice that can help inform treatment decisions. These COLLIGO-HCM real-world effectiveness and safety data build on the well-established clinical program for Camzyos, which has consistently demonstrated reduction in obstruction and effective and lasting symptom improvement. Our clinical program and long-term extension analyses span nearly six years combined, and we look forward to continuing to demonstrate the long-term effectiveness and safety of Camzyos in real-world settings across diverse patient populations as part of our global WAYFARER-HCM program.”
A New Global Standard of Care
Camzyos has already been recognized as a standard of care for symptomatic oHCM and is included in both European Society of Cardiology (ESC) and American Heart Association/American College of Cardiology (AHA/ACC) clinical guidelines. Specifically, it is recommended for patients who remain symptomatic despite first-line therapies.
The inclusion of Camzyos in guidelines reflects its status as the first therapy to directly target the underlying sarcomeric hypercontractility driving oHCM, rather than simply managing symptoms. The accumulating real-world evidence further solidifies its role in everyday cardiology practice worldwide.
Broader Implications for Cardiology
The success of Camzyos carries broader implications beyond hypertrophic cardiomyopathy:
- Validation of Targeted Myosin Inhibition
The positive Bristol outcomes validate the concept of modulating cardiac contractility at a molecular level, a strategy that could influence drug development for other forms of cardiomyopathy. - Equity in Research
The racial diversity of COLLIGO-HCM highlights the importance of including historically underrepresented groups in cardiovascular research. Such inclusivity ensures that therapies are validated across populations that reflect real-world practice. - Integration of Real-World Evidence
With increasing regulatory and payer interest in real-world data, the COLLIGO-HCM study demonstrates how post-approval evidence generation can complement trial results, support treatment guidelines, and inform clinical decision-making.
Bristol Myers Squibb remains committed to expanding its research into the long-term safety and effectiveness of Camzyos through the WAYFARER-HCM program. With Bristol over 3,000 patients enrolled globally, the program represents one of the most ambitious real-world initiatives in cardiology.
Future analyses are expected to provide even deeper insights into:
- Long-term outcomes beyond two years.
- Subgroup analyses by race, age, and comorbidities.
- Patterns of treatment initiation and discontinuation.
- Comparative outcomes between healthcare systems and regions.
The COLLIGO-HCM study, presented at ESC Congress 2025, adds a powerful layer of evidence supporting Camzyos as a transformative therapy for obstructive hypertrophic cardiomyopathy. With consistent improvements in symptom burden, robust reductions in LVOT Bristol gradients, and a reassuring safety profile across diverse populations, Camzyos continues to redefine expectations for patients living with this complex condition.
As the global Bristol cardiology community advances toward precision medicine, Camzyos serves as a model for how mechanism-based therapies, validated through both rigorous trials and real-world data, can transform the standard of care and meaningfully improve lives worldwide.
