Beam Therapeutics Reports Positive Updates on BEAM-302 Trial for AATD

Beam Therapeutics announced significant updates from its Phase 1/2 clinical trial of BEAM-302 for alpha-1 antitrypsin deficiency (AATD) at the European Respiratory Society (ERS) Congress 2026. The company presented data that suggest BEAM-302, a one-time treatment designed to correct the root cause of AATD, is demonstrating long-term durability and potential to address both lung and liver manifestations of the disease.

According to John Hurst, M.D., Ph.D., a professor at University College London and an investigator in the BEAM-302 trial, "BEAM-302 is leading the way as a novel medicine that can potentially provide a genetic cure and treat both the lung and liver disease manifestations in patients living with severe AATD."

The data from 29 patients who received a single dose of BEAM-302 showed rapid and durable increases in total and functional alpha-1 antitrypsin (AAT). Specifically, a single dose of 60 mg led to steady-state circulating total AAT levels of 14.4 µM and 15.2 µM, compared to baseline levels of 5.0 µM. This increase was functional, as human neutrophil elastase (HNE) activity levels decreased in a dose-proportionate manner, with more than 80% of patients in the 60 mg cohort having at least one HNE activity measurement below the lower limit of quantification.

Moreover, BEAM-302 significantly reduced mutant Z-AAT and toxic Z-polymers, which have been linked to liver disease severity and amplification of lung inflammation. One patient in the 60 mg cohort showed evidence of AAT protein production under normal physiologic control during an upper respiratory tract infection, indicating that the treated cells can respond appropriately to inflammation.

Amy Simon, M.D., Chief Medical Officer of Beam Therapeutics, noted, "These data reinforce the potential of BEAM-302 to address AATD at its root cause by correcting the disease-causing mutation and restoring production of functional AAT needed to prevent lung and liver damage with a single treatment."

The Phase 1/2 trial, which includes a global pivotal cohort, is now enrolling patients. Based on feedback from the U.S. Food and Drug Administration (FDA), Beam intends to pursue an accelerated approval pathway for BEAM-302 based on a primary endpoint of AAT biomarkers evaluated over 12 months. 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.

As of August 17, 2026, 38 patients have been dosed with BEAM-302 across the trial's two parts: Part A, which evaluates patients with AATD-associated lung disease, and Part B, which evaluates patients with mild to severe liver disease, with or without lung disease. Mild-to-moderate infusion-related reactions (IRRs) were the most common drug-related treatment-emergent adverse events (TEAEs), occurring in 41% of all patients. Transient and predominantly Grade 1 alanine transaminase (ALT) and/or aspartate transaminase (AST) elevations were also observed. One patient with underlying AATD-related liver disease treated with 60 mg BEAM-302 experienced transient Grade 3 ALT/AST elevations, but these did not require treatment.

The safety profile of BEAM-302 remains consistent with other LNP-based therapies. The company is set to host a conference call and webcast on September 8, 2026, to review these updates. Beam's next steps involve building on its scientific and clinical leadership in the field, with the goal of transforming the AATD treatment paradigm.

The ongoing trial is expected to provide further insights into the efficacy and safety of BEAM-302, potentially paving the way for a breakthrough treatment for AATD patients who have been waiting for effective, one-time therapies.