Prime Medicine, Inc. (Nasdaq: PRME) announced that New Zealand's Medicines and Medical Devices Safety Authority (Medsafe) has cleared the company's Clinical Trial Application for PM577a, an investigational Prime Editing therapy targeting Wilson Disease (WD).

According to the company, the clearance marks the first clinical authorization for an in vivo Prime Editing therapy from Prime Medicine. The company said it expects to initiate a Phase 1/2 clinical trial in the second half of 2026, with initial clinical data anticipated in 2027.

PM577a targets the H1069Q mutation in the ATP7B gene, which the company states accounts for approximately 30–50% of WD-associated variants in the United States and Europe. The therapy is delivered via a single intravenous infusion using a lipid nanoparticle (LNP) formulation.

The planned Phase 1/2 study is an open-label, first-in-human trial designed to evaluate safety, tolerability, biological activity, and efficacy of ascending doses in adults and adolescents with WD. The study will initially enroll adults who are clinically stable on standard-of-care therapy.

Wilson Disease is a rare genetic disorder affecting an estimated 1 in 30,000 individuals globally. Current treatments, including copper chelators and zinc salts, require lifelong daily dosing and are non-curative. Liver transplantation is currently the only curative option.

Prime Medicine said a follow-on candidate targeting the R778L mutation, the most common mutant allele in East Asian populations, is in preclinical development using the same LNP delivery platform.

"Wilson Disease is a well-characterized, serious genetic disorder with no approved curative option," said Allan Reine, M.D., Chief Executive Officer of Prime Medicine, in a statement based on the press release.