Secondary effects not only improved past 16 weeks, but showed a sustained improvement at week 56 of mavacamten, said Milind Desai, MD, MBA, director of the Hypertrophic Cardiomyopathy Center and vice chair of education at the Heart, Vascular & Thoracic Institute, Cleveland Clinic.
The VALOR-HCM randomized clinical trial assessed several key secondary end points, including postexercise left ventricular outflow tract (LVOT) gradient, New York Heart Association (NYHA) class, and cardiac biomarkers. According to Milind Desai, MD, MBA, director of the Hypertrophic Cardiomyopathy Center and vice chair of education at the Heart, Vascular & Thoracic Institute, Cleveland Clinic, these secondary effects not only improved past 16 weeks of mavacamten, but showed a sustained improvement at week 56.
How did the secondary end points evolve over the course of the VALOR-HCM trial?
We'll start with the principal end point, which was septal reduction therapy. At 16 weeks, 82% of people in the mavacamten arm no longer [qualified for septal reduction therapy (SRT)]. Remember, at baseline, 100% were referred for surgery. The naysayer comment could be, "This is just a short-term effect, because eventually everybody will end up with surgery." That was not the case. At week 56, [after] 56 weeks of exposure to mavacamten or 40 weeks in the placebo crossover group, 89, so 9 out of 10 patients, continued to be on mavacamten. They did not choose SRT. So the effects are sustained while on mavacamten.
Additionally, all the secondary efficacy end points—those include postexercise gradient, biomarkers, LA [left atrial] volume, LV mass, Kansas City Questionnaire, NYHA class—everything not only improved past 16 weeks in favor of mavacamten, but showed a sustained improvement at week 56. So it is not just a short-term and then everything gets back to baseline. No, it shows sustained improvement. And, importantly—I think this is going to be the important thing in the long run—it showed favorable remodeling characteristics, so the heart is also structurally remodeling in a good and a sustained way.
Were there similar trends among patients who started in the placebo group?
Yes, obviously lagging behind the 16 weeks, but we saw almost exactly the same pattern of improvement in the placebo crossover group, and that was the primary reason for designing the study the way we did.
This transcript has been lightly edited for clarity.