Prime Medicine (PRME) investor relations material

Company progress and strategic focus

• Preparing to initiate first in vivo liver-directed clinical programs for Wilson disease and alpha-1 antitrypsin deficiency, with regulatory filings expected in the first half and middle of the year, respectively.

• Advancing cystic fibrosis program with support from the Cystic Fibrosis Foundation, aiming for preclinical proof of concept data this year.

• Ex vivo CAR T therapies progressing in collaboration with BMS, with up to $185 million in preclinical milestones tied to the partnership.

• Announced intent to file a BLA for the Chronic Granulomatous Disease (CGD) program, reversing a prior discontinuation decision due to evolving FDA guidance and strong clinical data.

• Cash runway extends into 2027, covering major upcoming data events and clinical milestones.

Clinical pipeline updates

• Wilson disease program targets high unmet need, aiming to restore normal copper metabolism and reduce patient burden; initial clinical data expected in 2027.

• Alpha-1 antitrypsin deficiency program leverages Prime Editing to revert mutated genes to wild type, with initial clinical results also anticipated in 2027.

• Cystic fibrosis program focuses on patients not eligible for standard therapies, with lead optimization underway and preclinical progress ongoing.

• Ex vivo CAR T cell therapy development is outsourced to BMS, allowing focus on core in vivo programs.

Regulatory and commercial strategy

• CGD BLA filing planned, with timing dependent on further alignment with FDA; decision influenced by potential for expedited approval in rare diseases.

• Wilson disease trial will use biomarkers such as radiolabeled copper PET and urinary copper to demonstrate proof of concept and support potential accelerated approval.

• For Wilson disease, initial Prime Editor targets H1069Q mutation (30%-50% of Western patients), with plans to expand to cover up to 60% globally; different editors will address regional mutation prevalence.

• Arbitration with Beam Therapeutics over Prime Editing rights expected to resolve in the first half of the year.