Overview

• YCT-529 selectively blocks retinoic acid receptor α in the testes to halt sperm production without altering testosterone levels or libido.
• In a randomized, double-blind Phase I study of 16 vasectomized men, single oral doses up to 180 mg produced no serious adverse events or clinically relevant hormonal changes.
• Pharmacokinetic data showed blood concentrations matching those needed for reversible infertility in animal models, with half-lives of 51–76 hours and a modest food effect.
• The ongoing trial will administer daily doses for 28 and 90 days in more than 50 participants to confirm long-term tolerability and degree of sperm suppression.
• Preclinical studies demonstrated over 99 percent effectiveness in mice and nonhuman primates with full restoration of fertility after treatment cessation.