Prime Medicine selects PM647 as development candidate for Alpha-1 Antitrypsin Deficiency

Prime Medicine/PM647

Prime Medicine announced PM647 as its development candidate for Alpha-1 Antitrypsin Deficiency (AATD), an inherited liver disease where the SERPINA1 gene produces faulty alpha-1 antitrypsin. The candidate uses Prime's universal liver lipid nanoparticle to deliver prime editors that correct the E342K (Pi*Z) mutation. In humanized mouse models, PM647 achieved high editing efficiency and restored corrected AAT protein to normal healthy levels at clinically relevant doses.

• Targets the E342K (Pi*Z) mutation, the most common disease-causing variant in AATD.
• Preclinical efficacy: up to 72% precise correction in humanized mouse hepatocytes with M-AAT restored to healthy serum levels.
• IND and/or CTA filing planned for Q3 2026; initial clinical data expected in 2027.
• Builds on Prime's universal liver LNP platform, which the company is adapting for multiple genetic liver diseases.