Beam base editing therapy gets orphan drug status in AATD

The U.S. FDA has granted Beam Therapeutics orphan drug designation for BEAM-302, a liver-targeting lipid-nanoparticle formulation of a guide RNA and an mRNA encoding a base editor designed to correct the disease-causing mutation in patients with alpha-1 antitrypsin deficiency (AATD).

AATD is an inherited genetic disorder — with no approved curative treatments — that affects the lungs and/or liver, leading to early onset emphysema and liver disease. There is significant unmet need for effective therapies that can treat the entire spectrum of disease.

A number of genetic mutations cause AATD, but it’s estimated that approximately 100,000 individuals in the U.S. have the PiZZ genotype. Patients with this genotype have very low circulating levels of functional alpha-1 antitrypsin (AAT) protein, all of which is the mutant form, known as Z-AAT, which accumulates and causes liver toxicity. By correcting the PiZ mutation at the DNA level, BEAM-302 has the potential to be a one-time therapy that simultaneously reduces the amount of Z-AAT in circulation, generates therapeutic levels of corrected protein (M-AAT), and increases total and functional AAT in circulation above the 11µM protective threshold, thereby addressing the underlying pathophysiology of both the liver and lung disease.

Beam previously announced the clearance of its IND application for BEAM-302 in March 2025. Just prior to that, Beam shared initial safety and efficacy data from the ongoing phase 1/2 trial outside of the U.S. as it readied to expand patient enrollment and activate new clinical sites in the U.S. Preliminary results from the first three single-ascending dose cohorts demonstrated that BEAM-302 was well tolerated, with single doses of BEAM-302 leading to durable dose-dependent correction of the disease-causing mutation.