PBGM01 is an adeno-associated viral vector serotype Hu68 carrying GLB1, the gene encoding for human beta-galactosidase, formulated as a solution for injection into the cisterna magna. This is a global interventional, multicenter, single-arm, dose escalation, adaptive design study of PBGM01 delivered as a one-time dose administered into the cisterna magna to patients with infantile GM1 gangliosidosis. There are two infantile subtypes of GM1 gangliosidosis: early onset infantile (Type 1) and late onset infantile (Type 2a) which are defined by the age of onset of disease symptoms.~Early Onset Infantile (Type 1):~Onset <6 months of age~Age at enrollment: >4 to <24 months of age~Late Onset Infantile (Type 2a):~Onset >6 to 18 months of age~Age at enrollment: >6 to <36 months of age (except Cohort 1 will be >12 to <36 months of age)~In Part 1 of the study, two dose levels of PBGM01 will be studied separately in patients with either Type 1 or Type 2a GM1 gangliosidosis (see table below). The cohorts for patients with Type 1 and Type 2a will be assessed independently from each other. Part 1 will enroll a total of four cohorts, enrolled sequentially with separate dose-escalation cohorts for Type 1 GM1 and Type 2a GM1. Enrollment will initiate in Cohort 1. Following completion of Cohort 1, simultaneous enrollment in Cohort 2 and Cohort 3 will occur. Cohort 4 will follow completion of cohort 3.~Part 2 of the study will test the safety and efficacy of PBGM01 in confirmatory cohorts for Types 1 and Type 2a GM1 gangliosidosis with a dose chosen based on the data obtained in part 1 of the study. This will be a 2-year study with a 3-year safety extension.
PBGM01 is a gene therapy for GM1 gangliosidosis intended to deliver a functional copy of the GLB1 gene to the brain and peripheral tissues. This study will assess in a 2-stage design the safety, tolerability and efficacy of this treatment in patients with early onset infantile (Type 1) and late onset infantile (Type 2a) GM1 gangliosidosis. Results from the Type 1 and Type 2a groups will be assessed separately.