Clinical: Beam Advances Base Editing For PKU

PKU is caused by pathogenic variants in the PAH gene, leading to accumulation of phenylalanine and potentially severe neurological consequences. BEAM-304 uses Beam’s adenine base-editing technology delivered to the liver by lipid nanoparticles (LNPs) to directly correct disease-causing PAH mutations. The initial clinical programme will focus on the common R408W variant, with plans to evaluate additional mutation-specific editors within the same development platform. According to Beam, preclinical studies in PKU mouse models showed robust on-target editing in the liver and normalisation of plasma phenylalanine levels at clinically relevant doses.

The planned Phase 1/2 open-label trial will assess safety, tolerability, pharmacological effects, blood phenylalanine reduction and dietary liberalisation. The approach reflects emerging FDA guidance intended to streamline development of genome-editing therapies that share a common editing technology, delivery system and manufacturing process. If successful, the strategy could provide a framework for treating genetically heterogeneous liver disorders through mutation-specific base editors.

The news was announced by Beam Therapeutics in a press release on 18 June 2026.