A clinical trial that aims to determine the efficacy and tolerability of gene therapy using adeno-associated virus vectors for treating infantile-onset Pompe disease (PD) is now recruiting participants.

This interventional study is initiating a single-arm, open-label, multicenter, nonrandomized trial. Approximately 6 participants, from newborns to 6-month-old infants of either sex, previously diagnosed with PD, will be part of this research.

The intervention consists of administering escalating doses of GC301, an adeno-associated virus 9 that will deliver a functional copy of the human GAA gene. The initial dose cohort will consist of 1.2×1014 vg/kg of the compound, followed by a second dose of 2.4×1014 vg/kg in an intravenous formulation.

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The study will measure the overall tolerability and safety over time, during at least 1 year of follow-up, as the primary outcome. To assess this, the researchers will record the type and frequency of adverse events and serious adverse events, as well as modifications from laboratory test values.

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As for the secondary outcomes, the trial will evaluate the proportion of patients that survived without ventilatory support after receiving the gene therapy, variations in left ventricular mass, and creatine kinase after 26 and 52 weeks.

Other outcome measures at both timeframes will include changes from baseline in glycogen content in muscle tissue and acid alpha-glucosidase enzyme in muscle and blood. Likewise, the Hammersmith Infant Neurological Examination score will address motor function improvement at 52 weeks. Finally, all participants will undergo an evaluation of the adeno-associated virus viral load at various checkups after administration.

Patients younger than 6 months, with a confirmed diagnosis of PD, and whose legal guardian voluntarily consented after a complete understanding of the study’s purpose and risk may become part of the sample.

Individuals with organ dysfunction unrelated to PD, such as liver abnormalities, encephalopathy, neuropsychiatric symptoms, toxic tympanic bowels, hyperalbuminemia of 171 μmol/L or more, creatinine of 110 μmol/L of higher, or glomerular filtration rate lower than 100 mL/min cannot participate.

Likewise, infants born with organ agenesis, primary immunodeficiency, positive infection with human immunodeficiency virus, hepatitis B virus, hepatitis C virus, or treponema pallidum, or evidence of glucocorticoid allergy will not be part of the study.

This clinical trial is anticipated to start in August 2022 and is expected to be completed by September 2025.


Clinical exploration of adeno-associated virus (AAV) expressing human acid alpha- glucosidase (GAA) gene therapy for patients with infantile-onset Pompe disease. ClinicalTrials.gov. October 5, 2022. Accessed October 6, 2022.