Nexviazyme achieves all primary and secondary endpoints in Sanofi’s infantile-onset Pompe disease Phase 3 trial

Encouraging findings from the Baby-COMET Phase 3 single-arm, open-label study have confirmed that Nexviazyme  satisfied its primary endpoint: the proportion of treatment-naïve paediatric participants aged six months and under with infantile-onset Pompe disease who remained alive and free of invasive ventilation after 52 weeks of treatment. Every secondary endpoint was also achieved, among them the proportion of participants alive and free of invasive ventilation at 12 and 18 months of age, alongside numerical gains across additional markers of disease progression at the 52-week timepoint.

The findings will be presented on July 8, 2026 at the 19th International Congress on Neuromuscular Diseases in Florence, Italy. The dataset will also underpin a regulatory submission for a label extension in the US, which Sanofi anticipates filing in the second half of 2026.

Pompe disease is a rare inherited progressive neuromuscular condition arising from a deficiency of the acid alpha-glucosidase enzyme, which plays a vital role in muscle function throughout the body. Infantile-onset Pompe disease represents the most severe form of the condition, with symptoms escalating rapidly within the first months of life. Without treatment, it gives rise to serious and potentially life-threatening complications affecting the heart, breathing, and movement.

Nexviazyme has been developed as a potential therapeutic option for infantile-onset Pompe disease, engineered to enter cells and improve uptake of the GAA enzyme. This mechanism may help clear the excess glycogen that accumulates in muscle cells and drives damage to both skeletal and cardiac muscle tissue.

Throughout the Baby-COMET study, Nexviazyme was well tolerated and the safety profile remained consistent with what has already been established for avalglucosidase alfa. No serious treatment-related adverse events, deaths, or discontinuations were recorded, and infusion-associated reactions, which arose in 29.4% of participants, were considered manageable.

“Infantile-onset Pompe disease is a devastating, rapidly progressive condition that presents within the first days or weeks of life, making early intervention critical to help improve invasive ventilator-free survival beyond one year,” said Priya S. Kishnani, MD, C.L. and Su Chen Professor of Pediatrics, Medical Director of the YT and Alice Chen Pediatrics Genetics and Genomics Center, and Division Chief of Medical Genetics at Duke University Medical Center. “The Baby-COMET study shows the potential of avalglucosidase alfa to support ventilator-free survival in infants, alongside encouraging cardiac and motor outcomes, offering important insights that may help advance the treatment landscape for these patients.”

“These positive results offer the potential to expand access of Nexviazyme to more patients and families facing a condition with limited treatment options in the earliest months of life,” said Christopher Corsico, Global Head of Development at Sanofi. “The Baby-COMET findings are consistent with previous studies and reflect years of our scientific research aimed at translating deep biological understanding into clinical advances for the Pompe community.”

Nexviazyme holds approval across multiple countries for the treatment of Pompe disease, with the precise indications varying by market. Within the US, the medicine received approval in 2021 for late-onset Pompe disease in patients aged one year and above. Across Europe, where it is marketed as Nexviadyme, approval was granted in 2022 covering long-term enzyme replacement therapy in both late-onset and infantile-onset Pompe disease.

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Nexviazyme®, Phase 3 trial, Sanofi