Prime Medicine clears path for two liver programs, gains RMAT for PM359

Prime Medicine reported second quarter 2026 results on August 6, 2026, with several pipeline advances announced alongside the financials.

Following clearance of the Company's Investigational New Drug (IND) application in the United States and Clinical Trial Application (CTA) in New Zealand, PM577a is progressing into a global Phase 1/2 program and study startup activities are underway.¹ The IND clearance came in July 2026, and opened participation to patients in the United States, where the ATP7B H1069Q variant that PM577a targets is the single most common cause of WD.¹ The open-label, first-in-human study will evaluate the safety, tolerability, biological activity and efficacy of ascending doses of PM577a in adults and adolescents with WD, initially enrolling adults who are clinically stable on standard-of-care therapy.¹ Initial clinical data are anticipated in 2027.¹

In Alpha-1 Antitrypsin Deficiency, Prime Medicine announced in July 2026 a positive, binding resolution of its previously disclosed arbitration with Beam Therapeutics, Inc., in which the Tribunal declared that PM647 is within Prime Medicine's "Field" as defined by the parties' 2019 agreement, that Prime Medicine did not breach the agreement, and that no monetary damages are owed.¹ The company expects to submit an IND and/or CTA for PM647 in AATD in the third quarter of 2026, with initial clinical data from both programs expected in 2027.¹

For chronic granulomatous disease, the FDA granted Regenerative Medicine Advanced Therapy designation to PM359 in June 2026 based on Phase 1/2 clinical data, including data previously published in The New England Journal of Medicine.¹ Prime Medicine continues to engage with the FDA on the most efficient path to a BLA submission planned for the first half of 2027.¹

On financials, cash, cash equivalents, investments, and restricted cash were $108.8 million as of June 30, 2026, compared to $191.4 million as of December 31, 2025.¹ The company said this is expected to fund operations into 2027.¹