ESSA Pharma

ESSA Pharma, based in Vancouver and listed as EPIX, developed masofaniten, also known as EPI-7386, an inhibitor of the androgen receptor N-terminal domain, a target chosen because resistance to existing prostate cancer drugs often runs through that part of the receptor. Its phase 2 trial of masofaniten with enzalutamide in metastatic castration-resistant prostate cancer was terminated after a futility analysis on the PSA90 endpoint in 2024 to 2025, development was discontinued and strategic options are under review. OnCo keeps the record as an instructive failure for the AR N-terminal domain concept. Whether the target was wrong or the molecule was insufficiently potent is the question the failure leaves open. Masofaniten has its own page.