Beam doses the first patient in a pivotal base-editing trial

Beam Therapeutics disclosed on 4 August 2026, alongside its second-quarter results, that it dosed the first patient in the global pivotal cohort of the Phase 1/2 trial of BEAM-302. The dosing happened in July; the announcement is the public record of it.

BEAM-302 targets alpha-1 antitrypsin deficiency, an inherited condition in which a single mutation in SERPINA1 produces a misfolded protein that damages the liver and leaves the lungs unprotected. The therapy is a liver-targeted base editor: rather than adding a working copy of the gene or silencing the broken one, it chemically rewrites the mutated base in place, which is why the company describes it as correcting the root cause of both the lung and the liver manifestations at once.

A pivotal cohort inside a Phase 1/2 is the point where an editing programme stops being a demonstration and starts being a drug application. Updated clinical data is scheduled as a late-breaking presentation at the European Respiratory Society Congress in Barcelona, 5-9 September 2026 — which is when the result, rather than the milestone, becomes readable.

Beam held $1.2 billion at 30 June and states a cash runway into mid-2029.