Beam Therapeutics expands pipeline with BEAM-304, a base editing therapy for PKU affecting 20K US patients, plus Pfizer’s opt-in to a liver-targeted program unlocking durable genetic treatments.
Written By: Sana Khan BPharm
Reviewed By: Pharmacally Editorial Team
Beam Therapeutics Inc. highlighted two key pipeline developments in its February 24, 2026, press release: the launch of BEAM-304 for phenylketonuria (PKU) and Pfizer’s opt-in to a separate liver-targeted base editing program. These moves showcase Beam’s expanding genetic medicine platform via base editing and LNP delivery, both target liver genetic diseases but remain distinct programs.
Announced alongside its Q4 2025 updates BEAM-304 addresses a critical unmet need in PKU, a rare inherited disorder affecting about 20,000 people in the U.S.
Understanding PKU and BEAM-304’s Approach
PKU stems from mutations in the phenylalanine hydroxylase (PAH) gene, causing toxic buildup of phenylalanine (Phe) in the blood. Without intervention, this leads to severe neurologic and neurocognitive damage, forcing patients into lifelong strict dietary restrictions and medical foods.
BEAM-304 tackles the root cause by directly correcting these PAH mutations in liver cells, aiming to normalize Phe levels, restore natural diet freedom, and deliver a one-time, durable treatment.
The program uses multiple mutation-specific base editors delivered via Beam’s optimized LNP system, which has shown preclinical success: in mouse models, it normalized plasma Phe at clinically relevant doses with high on-target liver editing and minimal off-target effects.
What sets BEAM-304 apart is its innovative “multi-editor” strategy within a single clinical program. This efficient design starts with the two most common U.S. variants (covering nearly half of patients), like R408W, then expands to others. Preclinical data supports broad applicability, potentially transforming care for the vast majority of PKU patients.
Clinical Path Forward
Beam plans to submit an investigational new drug (IND) application to the FDA in 2026 after pre-IND completion. The Phase 1/2 trial will first assess safety, tolerability, and Phe reduction in R408W patients, followed by a second mutation-specific editor. Success here could establish proof-of-concept for base editing in PKU and pave the way for pivotal trials.
This builds on Beam’s liver-targeted momentum. For context, lead program BEAM-302 (for alpha-1 antitrypsin deficiency) aligned with FDA on accelerated approval via biomarkers, with updated Phase 1/2 data expected by Q1 2026 end. BEAM-301 (for glycogen storage disease Ia) has dosed its first cohort, with initial data slated for 2026.
CEO John Evans emphasized the scalability: “BEAM-304 exemplifies the power of our platform to pursue efficient development for multiple patient subsets in one program; one of the first to reach the clinic.”
This expansion underscores Beam’s strategy to deploy base editing across high-need genetic diseases, leveraging proven tech for faster paths to patients.
Strategic Pfizer Collaboration
In addition to its clinical development momentum, Beam has advanced a key partnership with Pfizer. In December 2025, at the end of their four-year research collaboration on in vivo base editing programs, Pfizer opted into an exclusive worldwide license for a distinct liver-targeted development candidate employing Beam’s proprietary LNP delivery.
Pfizer now assumes full responsibility for development, regulatory approvals, manufacturing, and commercialization of this unnamed program. Beam stands to receive development, regulatory, and commercial milestones, plus royalties, with an option to opt-in post-Phase 1/2 for co-development and co-commercialization on a 35%/65% profit/cost split (Beam/Pfizer).
This non-dilutive alliance provides Beam with strategic funding and validation of its base editing platform, complementing internal efforts like BEAM-304 without overlap.
This expansion underscores Beam’s strategy to deploy base editing across high-need genetic diseases, leveraging proven tech for faster paths to patients.
Reference
Beam Therapeutics Reports Fourth Quarter and Year-End 2025 Financial Results and Announces New Liver-Targeted Genetic Disease Program in Phenylketonuria (PKU), 24 February 2026, https://investors.beamtx.com/news-releases/news-release-details/beam-therapeutics-reports-fourth-quarter-and-year-end-2025
About Writer
Sana Jamil Khan, B.Pharm
She is a pharmacy graduate with a keen interest in clinical research, pharmacovigilance, and medical writing, with a growing focus on publication and scientific content development. In her words, she is passionate about translating complex medical data into clear, evidence-based communication.