The U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to venglustat, an investigational oral therapy developed by Sanofi, for the treatment of neurological symptoms associated with type 3 Gaucher disease (GD3), a rare genetic disorder with limited treatment options.

The decision is based on findings from the Phase 3 LEAP2MONO study, where patients treated with venglustat showed statistically significant improvements in neurological function compared to those receiving standard enzyme replacement therapy (ERT), imiglucerase. The improvements were measured using a composite global test score that assessed both motor coordination and cognitive function.

According to the study results, venglustat demonstrated a favorable safety profile, with no new safety concerns identified. Common side effects included headache and nausea, while some patients also reported spleen enlargement and diarrhea. Overall tolerability was comparable to the existing ERT treatment.

Gaucher disease is a rare inherited condition caused by a deficiency of the enzyme glucocerebrosidase, leading to the buildup of fatty substances known as glycosphingolipids in various organs. Type 3 Gaucher disease is characterized by both systemic symptoms—such as enlarged liver and spleen, anemia, and bone complications—and progressive neurological involvement.

While current therapies like ERT are effective in managing systemic symptoms, they do not address neurological complications, leaving a significant unmet medical need. Venglustat is designed to cross the blood-brain barrier and reduce the accumulation of harmful substances in the central nervous system, targeting the root cause of neurological damage.

“This designation underscores the urgent need for treatments that address neurological decline in patients with type 3 Gaucher disease,” said Karin Knobe, Global Head of Clinical Development for Rare Diseases at Sanofi. She added that the company will continue working closely with the FDA to advance the therapy through the regulatory process.

The LEAP2MONO trial enrolled 43 patients aged 12 and older, all of whom had been on ERT for at least three years prior to the study. Participants were randomly assigned to receive either once-daily oral venglustat or continued ERT over a 52-week period. The trial is ongoing, with additional results from its open-label phase expected in the future.

Venglustat has previously received Fast Track and Orphan Drug designations in multiple regions, including the United States, European Union, and Japan. Sanofi plans to pursue global regulatory filings for the therapy in 2026.

Breakthrough Therapy designation is intended to accelerate the development and review of drugs that show substantial improvement over existing treatments for serious or life-threatening conditions. The latest move signals growing momentum for venglustat as a potential first-in-class option for addressing the neurological burden of type 3 Gaucher disease.