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# Beam Gets OK to Begin Clinical Testing of PKU Gene-Editing Therapy
- URL: https://www.fdaweb.com/beam-gets-ok-to-begin-clinical-testing-of-pku-gene-editing-therapy/
- Published: 2026-06-19T12:00:00.000Z
- Updated: 2026-09-14T13:41:30.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5161340

FDA has given Beam Therapeutics the green light in its IND for BEAM-304, allowing the company to begin clinical testing of its experimental base-editing treatment for phenylketonuria (PKU).

The clearance enables the launch of a Phase 1/2 trial evaluating BEAM-304, an *in vivo* gene-editing therapy designed to directly correct disease-causing mutations in the phenylalanine hydroxylase (PAH) gene, according to the company. PKU is a rare inherited metabolic disorder that causes toxic accumulation of phenylalanine, potentially leading to severe neurological and cognitive impairments if left uncontrolled.

According to Beam Therapeutics, the program is being developed under a platform-based strategy that could allow multiple mutation-specific base editors to be advanced through a single clinical program. The company says the approach aligns with emerging FDA efforts to streamline development of genome-editing therapies.

BEAM-304 uses Beam's proprietary base-editing technology and lipid nanoparticle delivery system to make precise DNA changes in liver cells. The company aims to restore PAH enzyme activity, reduce phenylalanine levels to recommended targets and potentially eliminate the need for lifelong dietary restrictions and medical foods.

The planned Phase 1/2 study will initially enroll PKU patients with the R408W mutation, one of the most common disease-causing variants. A second mutation-specific editor is expected to be evaluated later in the trial. Beam said the strategy could ultimately address mutations found in nearly half of U.S. PKU patients.