Beam Therapeutics expanded its liver‑targeted gene‑editing portfolio with BEAM‑304, a multi‑editor program designed to correct common PAH mutations that cause phenylketonuria (PKU). The company reported preclinical data showing normalization of plasma phenylalanine in mouse models using lipid nanoparticle delivery of base editors and said it plans an IND filing in 2026 to start a Phase I/II trial. Beam is developing multiple mutation‑specific base editors within one clinical program to address a broad patient population and aims for a one‑time therapeutic approach.