BEAM-304

June 18, 2026: Beam Therapeutics Inc. (NASDAQ: BEAM) announced FDA clearance of its IND for BEAM-304, an in vivo, liver-targeted lipid nanoparticle (LNP) base-editing therapy for phenylketonuria (PKU) caused by mutations in the phenylalanine hydroxylase (PAH) gene. The program uses a “platform” development approach intended to efficiently advance multiple mutation-specific base editors within a single clinical program, aligned with emerging FDA efforts to accelerate genome editing therapy development.

Beam said BEAM-304 is designed to durably correct PAH mutations to restore PAH enzyme activity and reduce toxic plasma phenylalanine (Phe) toward guideline levels (≤360 µmol/L), potentially enabling diet normalization.

Preclinical data cited showed normalization of plasma Phe in PKU mouse models at clinically relevant doses with robust on-target liver editing. Updated preclinical data are planned for presentation at the FASEB Genome Engineering: Research and Applications Conference (July 6–9, 2026; Porto, Portugal).

The planned Phase 1/2 trial will initially assess safety, tolerability, blood Phe reduction, and diet liberalization in patients with the R408W mutation, then evaluate a second mutation-specific editor.