PM577

July 23, 2026: Prime Medicine, Inc. (NASDAQ: PRME) announced FDA clearance of its IND for PM577a, an investigational in vivo Prime Editor for Wilson disease (WD), allowing the program to proceed to clinical study in the U.S. The IND clearance, together with a previously cleared New Zealand Clinical Trial Application (CTA), establishes a global Phase 1/2 clinical program.

PM577a is an LNP-formulated prime editing product designed as a single IV infusion to correct pathogenic ATP7B mutations in hepatocytes, targeting the H1069Q variant (described as the most prevalent WD-causing allele in North America and Europe; ~30–50% of WD-associated variants in the U.S. and Europe).

The planned Phase 1/2 trial is an open-label, global, first-in-human, ascending-dose study in adults and adolescents with WD; initial enrollment will be adults clinically stable on standard-of-care therapy. Assessments may include 64Cu PET copper efflux, serum ceruloplasmin, non-ceruloplasmin bound copper, 24-hour urinary copper excretion, and hepatic copper by biopsy.

Timing: trial initiation expected in 2H 2026; initial clinical data anticipated in 2027. A follow-on candidate targeting R778L is noted as preclinical.