Early data from six patients suggest a single dose of BEAM-301 may improve fasting tolerance and reduce starch requirements in glycogen storage disease type Ia.
Beam Therapeutics is preparing to present early human data from its Phase I/II study of BEAM-301, an experimental base-editing treatment for glycogen storage disease type Ia, at the 33rd Annual Congress of the European Society of Gene and Cell Therapy.
According to the company’s update, the therapy is designed to correct the R83C mutation, which it describes as one of the most common disease-causing changes linked to GSDIa and among the variants associated with the severest forms of the disorder. BEAM-301 uses a liver-targeting lipid nanoparticle, or LNP, to deliver base-editing components directly to the liver, where the disease disrupts the body’s ability to maintain blood sugar during fasting.
As of the June 2026 data cut-off, six patients had received a single intravenous dose, split evenly between the 20mg and 40mg cohorts. Beam said the treatment showed an acceptable safety profile consistent with other LNP-based therapies, while also producing signs of improved fasting tolerance. In the lower-dose group, the median time to fasting hypoglycaemia increased from 2.9 hours at baseline to 4.3 hours by day 36. In the higher-dose group, both evaluable patients reached the protocol-defined maximum controlled fasting period of at least 15 hours, which the company said was consistent with restored endogenous glucose production.
The company also reported reductions in the amount of starch prescribed each day, a standard dietary measure used to help prevent dangerous drops in blood glucose in people with GSDIa. According to Beam’s figures, patients in both dose groups needed less starch after treatment, with the largest reductions seen in the higher-dose cohort at earlier follow-up points. Triglyceride levels were broadly similar to baseline at the latest assessments.
Amy Simon, Beam’s chief medical officer, said the findings offered the first clinical evidence that BEAM-301 may correct the underlying defect in people with GSDIa and help restore the body’s own glucose production after one treatment. The results remain preliminary, but they will be closely watched as one of the first real-world tests of whether base editing can move beyond laboratory promise and into durable benefit for a rare metabolic disease.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
