San Carlos, California-based Glycomine, Inc. has received US FDA Breakthrough Therapy Designation (BTD) for GLM101, an investigational liposomal mannose-1-phosphate (M1P) substrate replacement therapy for phosphomannomutase 2 congenital disorder of glycosylation (PMM2-CDG), a multisystem disorder for which no approved treatments currently exist.
GLM101 bypasses loss-of-function mutations in the PMM2 enzyme by delivering mannose-1-phosphate directly into cells via a liposomal nanoparticle, restoring the N-glycosylation pathway without requiring functional PMM2 activity. Glycomine had previously received Fast Track Designation for GLM101 on September 18, 2024, also for PMM2-CDG.
The BTD is grounded in data from an open-label Phase IIa study, in which nine adult and adolescent patients treated with GLM101 showed a mean 11.9-point improvement on the International Cooperative Ataxia Rating Scale (ICARS; scored 0–100, higher scores indicating greater impairment) over 24 weeks. No serious adverse events were reported in the Phase IIa study; all adverse events were characterized as mild-to-moderate in severity.
The BTD enables more frequent interactions with the FDA as Glycomine analyzes data from the ongoing POLAR study and determines next steps for GLM101, according to CEO Steven Axon. GLM101 is currently being evaluated in POLAR (NCT06892288), a global, randomized, double-blind, placebo-controlled Phase IIb study that enrolled 43 pediatric and adult patients across 15 sites in the US, UK, and Europe, with ataxia improvement as measured by ICARS as the primary endpoint. Topline data from the randomized portion of POLAR are expected in Q4 2026.