Early Phase I/II findings suggest a single dose of Beam Therapeutics’ base-editing therapy may restore glucose production and reduce patients’ dependence on starch supplementation.
Beam Therapeutics will present early clinical findings on BEAM-301 at the 33rd Annual Congress of the European Society of Gene and Cell Therapy, offering the first public look at how the experimental treatment is performing in people with glycogen storage disease type Ia. The company says the therapy is being developed to address the R83C mutation, a common genetic change linked to one of the more severe forms of the disorder.
In the Phase I/II study, six patients had received a single intravenous dose by the June 2026 data cut-off, with three given 20mg and three given 40mg. Beam said the treatment showed an acceptable safety profile, with effects broadly in line with other lipid-nanoparticle, or LNP, medicines, which use tiny fat-based particles to deliver genetic material into cells.
The most striking signal so far has been an improvement in fasting tolerance, which is the length of time a patient can go without food before blood sugar falls dangerously low. At baseline, the median time to fasting hypoglycaemia was 2.9 hours in the 20mg group and 2.5 hours in the 40mg group. By day 36, the median had risen to 4.3 hours in the lower-dose cohort, while both evaluable patients in the 40mg group reached the trial’s maximum controlled fasting period of at least 15 hours, a result Beam said was consistent with restored endogenous glucose production.
The company also reported reductions in the amount of starch patients needed to take each day to help keep blood glucose steady. Guided by continuous glucose monitoring, prescribed starch intake fell from baseline levels by 74% on day 128, 71% on day 227 and 11% on day 387 in the 20mg cohort. In the 40mg cohort, the reductions were 71% on day 50 and 92% on day 93. Daily starch doses also declined, and triglyceride levels remained similar to baseline at the latest follow-up.
“People living with GSDIa face a relentless daily burden, including dependence on frequent starch administration, even throughout the night, to maintain glucose levels and prevent life-threatening hypoglycaemia,” Dr Amy Simon, Beam’s chief medical officer, said. “These initial data provide the first clinical evidence suggesting that BEAM-301, a base editing therapy designed to directly correct an underlying disease-causing mutation in patients with GSDIa, restored endogenous glucose production following a single in vivo treatment.”
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