Results From a Phase 2, Open-Label Study Evaluating the Safety, Tolerability, and Effect on Ataxia of GLM101 in Three Adult Patients With PMM2-CDG.

Phosphomannomutase 2 congenital disorder of glycosylation (PMM2-CDG) is a rare, autosomal recessive disease caused by PMM2 deficiency, which impairs conversion of mannose-6-phosphate into mannose-1-phosphate (M1P) and disrupts N-linked glycosylation. It typically results in a multisystem disorder in which a prominent cerebellar syndrome, characterized by ataxia among other clinical manifestations, can be assessed using the International Cooperative Ataxia Rating Scale (ICARS). GLM101 is a liposomal M1P substrate replacement therapy in clinical development. We present results conducted both within and outside the protocol-defined schedule from three adult patients enrolled in a Phase 2 study evaluating the efficacy, safety, and tolerability of GLM101 (NCT05549219). PMM2-CDG patients received weekly infusions of 30 mg/kg GLM101 for 24 weeks. Ataxia was measured by ICARS as standard of care. Absolute and percent change from baseline were calculated. Additional results reported include global impression of change scales (caregiver and clinician) and safety. Three adult patients (1 M, 2 F) completed 24 weeks of treatment. The mean (SD) baseline ICARS was 50.7 (19.0) and mean (SD) change from baseline was -14.0 (7.2) and -17.7 (3.1) at Weeks 12 and 24, respectively. Improvements were seen across all ICARS subdomains. All patients and clinicians reported global clinical improvement. GLM101 was well tolerated with no serious adverse events. Infusion-associated reactions were reported in one patient, with no need to interrupt the therapy. Safety findings showed no adverse trends. In conclusion, GLM101 was well tolerated and demonstrated potential for meaningful clinical benefit. These findings support continued evaluation of GLM101 in patients with PMM2-CDG.