Sanofi has announced positive topline results from its Phase 3 Baby-COMET study evaluating Nexviazyme (avalglucosidase alfa) in treatment-naïve infants aged six months or younger with Infantile-Onset Pompe Disease (IOPD), a rare and rapidly progressive genetic disorder.

The single-arm, open-label study achieved its primary endpoint, with participants remaining alive and free from invasive ventilation after 52 weeks of treatment. The study also met all key secondary endpoints, including survival without invasive ventilation at 12 and 18 months of age, while demonstrating numerical improvements in additional measures of disease progression after one year of therapy.

Sanofi said the findings will be presented on July 8, 2026, at the 19th International Congress on Neuromuscular Diseases in Florence, Italy. The company also plans to use the data to support a regulatory submission to expand Nexviazyme's US label for infantile-onset Pompe disease during the second half of 2026.

Pompe disease is a rare inherited neuromuscular disorder caused by a deficiency of the acid alpha-glucosidase (GAA) enzyme, resulting in the accumulation of glycogen in muscle cells. The infantile-onset form is the most severe variant, with symptoms appearing within the first weeks or months of life and rapidly progressing to life-threatening cardiac, respiratory and muscular complications if left untreated.

Nexviazyme is designed to improve the delivery of the GAA enzyme into cells, helping reduce glycogen accumulation and potentially limiting damage to skeletal and cardiac muscles.

According to the company, the therapy demonstrated a favourable safety profile in the Baby-COMET study, with no treatment-related serious adverse events, deaths or treatment discontinuations reported. Infusion-associated reactions occurred in 29.4 percent of participants and were considered manageable, while the overall safety profile remained consistent with previous studies of avalglucosidase alfa.

Priya S. Kishnani, Professor of Pediatrics and Division Chief of Medical Genetics at Duke University Medical Centre, said the findings highlight the importance of early intervention in infantile-onset Pompe disease, noting that the study showed encouraging improvements in ventilator-free survival as well as cardiac and motor function outcomes.

Christopher Corsico, Global Head of Development at Sanofi, said the results could help expand treatment options for infants diagnosed with the disease, adding that the findings reinforce the company's long-term commitment to advancing therapies for the Pompe disease community.

Nexviazyme is currently approved in several countries for Pompe disease, although approved indications vary by market. In the United States, the therapy received FDA approval in 2021 for treating patients aged one year and older with Late-Onset Pompe Disease (LOPD). In Europe, where it is marketed as Nexviadyme, the medicine was approved in 2022 for long-term enzyme replacement therapy in both late-onset and infantile-onset Pompe disease. However, the treatment remains under clinical investigation for IOPD in the United States, where its safety and efficacy for this indication have not yet been evaluated by the FDA.