A closely watched drug for a serious and underdiagnosed heart condition did not meet its main goal in a large international trial, and researchers say the most instructive part may be why. Eplontersen did not significantly reduce cardiovascular deaths and repeat cardiovascular events compared with placebo in the overall study population, according to late breaking results presented at ESC Congress 2026 in Munich and published simultaneously in the New England Journal of Medicine.
The condition is transthyretin amyloid cardiomyopathy, or ATTR-CM, in which a liver protein misfolds and deposits in heart muscle, progressively stiffening it. Long considered rare, it is now recognized through better imaging as a meaningful cause of heart failure in older adults, particularly men, and is often mistaken for other cardiac conditions for years. Presenting investigator Mathew Maurer of Columbia University Irving Medical Center estimated that 300,000 to 500,000 people are living with it worldwide.
