BEAM-302

September 8, 2026: Beam Therapeutics (NASDAQ: BEAM) reported updated Phase 1/2 data for BEAM-302 in alpha-1 antitrypsin deficiency (AATD) at the ERS Congress 2026. In 29 single-dose patients from dose-escalation cohorts, BEAM-302 showed rapid and durable increases in total and functional AAT, reductions in mutant Z-AAT and toxic Z-polymers, and production of corrected M-AAT.

At the 60 mg dose, steady-state total AAT rose above the 11 µM protective threshold: in Part A (lung disease), mean/median 14.4/15.2 µM vs 5.0 µM baseline; in Part B (mild to severe liver disease, with or without lung disease), 13.5/13.8 µM vs 4.7 µM baseline. Functional AAT increased dose-dependently, and >80% of Part A 60 mg patients had at least one human neutrophil elastase activity measurement below quantification. Circulating Z-AAT fell 84% in both Part A and Part B 60 mg cohorts, and corrected M-AAT comprised 93% of circulating AAT at steady state.

Safety as of June 24, 2026 was described as acceptable; 41% had mild-to-moderate infusion-related reactions, with transient mostly Grade 1 ALT/AST elevations and one transient Grade 3 ALT/AST event in a Part B patient.

Beam said dosing is underway in a global pivotal cohort after first-patient dosing in July, targeting a potential accelerated approval pathway and future BLA based on 12-month AAT biomarker endpoints.