Beam Therapeutics (BEAM) said Monday that initial data from a phase 1/2 trial of BEAM-302 show that a single dose led to "durable, dose-dependent" increases in total and functional alpha-1 antitrypsin, or AAT, protein across three initial dose levels, production of corrected protein M-AAT, and reduction in the amount of mutant protein Z-AAT in circulation.

BEAM-302 was well-tolerated at all dose levels, with an "acceptable" safety profile at all dose levels and no serious adverse events observed, the company also said.

AAT deficiency, or AATD, is a genetic disorder affecting the lungs and/or liver, leading to emphysema and liver disease.

Part A of the trial aimed to evaluate AATD in patients with lung disease, while part B will evaluate AATD patients with mild to moderate liver disease with or without lung disease, according to the company.

Beam said it intends to enroll and dose a fourth dose group in part A of the study and dose the first participant in part B in H2.

Shares of the company were down 2.6% in recent Monday premarket activity.