Milestone Pharmaceuticals (MIST) Study update summary

Overview of study and clinical context

• Etripamil is an investigational drug under FDA review for paroxysmal supraventricular tachycardia (PSVT), with a decision expected by the end of March next year.

• The event featured a fireside chat with two key opinion leaders, Dr. George Mark (electrophysiologist) and Dr. Vivek Sailam (clinical cardiologist), discussing PSVT management in a community-based setting.

• Both physicians emphasized the importance of community providers in managing the majority of PSVT patients and highlighted the need for practical, patient-centered interventions.

• The discussion included insights from the RAPID phase III pivotal trial and the NODE-303 open-label safety study for etripamil.

Disease burden and patient experience

• PSVT affects a diverse patient population, often undiagnosed for years, with episodes ranging from adolescence to old age.

• Patients frequently experience anxiety and loss of control due to unpredictable episodes, leading to significant quality-of-life impacts.

• Beta blockers, the most common chronic therapy, are associated with undesirable side effects and delayed onset, causing dissatisfaction.

• Ablation is effective but often considered a last resort due to procedural risks and patient reluctance.

Current treatment landscape and unmet needs

• Most PSVT patients are initially managed by general cardiologists, with only a subset referred to electrophysiologists for ablation.

• Chronic prophylaxis with beta blockers or calcium channel blockers is widely used but often ineffective or poorly tolerated.

• Pill-in-the-pocket strategies are limited by slow onset and practicality, especially during acute episodes.

• There is a clear unmet need for a rapid-acting, self-administered therapy that empowers patients to manage episodes outside the hospital.