The LANDMARK Trial

Background: In the LANDMARK trial, the Myval balloon-expandable transcatheter heart valve (THV) series was noninferior to the most commonly used contemporary SAPIEN and Evolut Series THVs for the 30-day early safety endpoint in participants with symptomatic severe native aortic stenosis. Objectives: The current report from the LANDMARK trial describes clinical outcomes, hemodynamic performances, and quality of life at 1 year. Methods: This open-label, noninferiority trial enrolled 768 participants across 31 hospitals in Europe, New Zealand, and Brazil. Participants were randomly assigned (1:1) to receive either a Myval THV series or a contemporary THV (SAPIEN or Evolut series). The composite endpoint at 1 year included all-cause mortality, all strokes, and procedure- or valve-related hospitalizations. Clinical efficacy was defined as freedom from the composite endpoint. As recommended in Valve Academic Research Consortium-3, the previous composite endpoint combined with the assessment of quality of life at baseline and 1 year with the 12-Item Short Form Health Survey was reported as an extended composite endpoint. The noninferiority hypothesis was prespecified for the assessment of the primary endpoint at 30 days. Considering the specific 1-year composite endpoints of Valve Academic Research Consortium-3 and the event rate of 27.23% derived from recent studies, an a posteriori descriptive and exploratory noninferiority hypothesis was introduced with a noninferiority margin of 10.89%. The analysis was performed in the intention-to-treat population. Results: The mean age was 80 years, 48% were women, and the median Society of Thoracic Surgeons Predicted Risk of Mortality score was 2.6%. There was no significant difference in the Kaplan-Meier estimates of freedom from the composite endpoint at 365 days (Myval THV 87.0% vs contemporary THVs 86.9%). The Myval THV series was noninferior to the contemporary THVs for the composite endpoint (difference: −0.1%; 1-sided 95% CI: 3.9%; Pnoninferiority < 0.0001). Similarly, there were no significant differences in freedom from the extended composite endpoint (80.5% vs 77.3%; difference: 3.2%; 95% CI: −2.9% to 9.2%; P = 0.33). Conclusions: In the treatment of symptomatic severe native aortic stenosis, the clinical and hemodynamic outcomes of the Myval THV series were comparable to those of contemporary THVs for the 1-year composite of all-cause mortality, all strokes, or procedure- or valve-related hospitalizations.