Beam Presents BEAM-302 Clinical Data in Alpha-1 Antitrypsin Deficiency, Advancing Toward Pivotal Development

May 18, 2026-

Beam Therapeutics presented recently reported clinical data from its BEAM-302 Phase 1/2 trial in alpha-1 antitrypsin deficiency (AATD) at the American Thoracic Society International Conference in Orlando. The presentation highlighted the potential of BEAM-302, a one-time investigational base editing therapy, to address AATD at its genetic root cause by correcting the disease-causing PiZ mutation in the native SERPINA1 gene.

AATD is an inherited genetic disorder that can cause both lung and liver disease. The most severe common form occurs in patients with two copies of the PiZ mutation, which causes alpha-1 antitrypsin protein to misfold and accumulate in the liver instead of being properly secreted into circulation. As a result, circulating functional AAT levels are significantly reduced, leaving the lungs vulnerable to neutrophil elastase–mediated tissue damage and increasing the risk of emphysema, liver inflammation, cirrhosis, liver failure, and transplant.

BEAM-302 is a liver-targeted lipid nanoparticle-formulated adenine base editing therapy designed to make a one-time A-to-G correction of the PiZ mutation. By correcting the native AAT gene in its normal genomic location, BEAM-302 has the potential to reduce toxic misfolded Z-AAT protein, generate functional M-AAT protein, and increase total and functional AAT levels in circulation. Importantly, Beam reported that corrected AAT expression can respond physiologically to infection and inflammation, which may represent a key distinction from currently approved protein replacement therapies.

The Phase 1/2 study is evaluating the safety, tolerability, pharmacodynamics, pharmacokinetics, and efficacy of BEAM-302. Beam previously reported topline data from 29 treated patients as of a February 10, 2026 data cutoff. At ATS, the company presented additional single-dose cohort data from the same cutoff, including detailed safety results, durability of efficacy, and reductions in human neutrophil elastase activity, a direct measure of AAT function after treatment.

Based on feedback from the U.S. FDA, Beam intends to pursue an accelerated approval pathway for BEAM-302. To support a future BLA submission, the company plans to enroll approximately 50 additional patients with AATD-associated lung disease, with or without liver disease, in an expansion of the ongoing open-label Phase 1/2 trial. Beam expects to initiate this pivotal cohort in the second half of 2026 and present additional updated data at a medical congress later in the year.

The BEAM-302 program reflects a broader shift in genetic medicine from gene addition toward precise gene correction. If successful, BEAM-302 could represent a disease-modifying approach for AATD by addressing both lung and liver manifestations through correction of the underlying DNA mutation with a one-time therapy.