Tectonic Therapeutic has completed enrollment of 191 patients in APEX, a Phase 2 trial testing TX45, a Fc-relaxin fusion protein designed to reduce pulmonary vascular resistance in heart failure with preserved ejection fraction. The trial's enriched design—72% of participants with elevated baseline resistance—positions it to detect meaningful improvements in a mechanistically distinct phenotype of heart failure that remains therapeutically limited.
Key Points
- 191-patient trial completed across 14 countries with 72% elevated resistance
- TX45 targets RXFP1 receptor with vasodilatory and anti-fibrotic mechanisms
- Primary endpoint measures pulmonary vascular resistance reduction over 24 weeks
Longevity Analysis
Heart failure with preserved ejection fraction represents a growing segment of the aging population with limited therapeutic options, particularly when combined with pulmonary hypertension. TX45's dual action on vascular resistance and myocardial stiffness addresses a fundamental constraint in this phenotype: the inability of the heart to relax and fill properly during diastole. Success here would validate targeting the relaxin pathway as a strategy to improve hemodynamic efficiency and exercise tolerance in older adults—outcomes that directly influence functional capacity and survival in this population.
Original published by Longevity.Technology.