Prime Medicine (PRME) investor relations material

Executive summary

• Cleared IND and CTA for PM577a in Wilson disease in the US and New Zealand, enabling a global Phase 1/2 trial with initial clinical data expected in 2027.

• Arbitration with Beam Therapeutics resolved favorably, affirming rights to PM647 for Alpha-1 Antitrypsin Deficiency; IND/CTA submission planned for Q3 2026.

• PM359 for chronic granulomatous disease received RMAT designation, with ongoing FDA engagement toward a BLA submission in H1 2027.

• Continued progress in Cystic Fibrosis and CAR-T programs, with ongoing collaborations and business development efforts.

Financial highlights

• Net loss for Q2 2026 was $42.1M, improved from $52.6M in Q2 2025; six-month net loss was $91.2M, improved from $104.5M year-over-year.

• R&D expenses were $33.4M and G&A expenses $11.0M for Q2 2026, both down year-over-year due to workforce and facility cost reductions.

• Collaboration revenue was $1.15M for Q2 2026, up slightly from $1.12M in Q2 2025; $2.01M for the six months, down from $2.57M year-over-year.

• Cash, cash equivalents, and short-term investments totaled $95.1M as of June 30, 2026; including restricted cash and investments, total was $108.8M.

Outlook and guidance

• Existing cash and investments expected to fund operations into 2027, but substantial doubt exists about ability to continue as a going concern without additional financing.

• Initial clinical data for PM577a and PM647 anticipated in 2027; BLA submission for PM359 planned for H1 2027.