FDA Grants Breakthrough Therapy for Sanofi’s Type 3 Gaucher Disease Drug

Rare Daily Staff

The U.S. Food and Drug Administration granted Breakthrough Therapy designation to Sanofi’s experimental drug venglustat for the treatment of neurological symptoms in type 3 Gaucher disease, a rare inherited disorder with limited options for brain-related complications.

Gaucher disease is a rare lysosomal storage disorder caused by a deficiency of the enzyme glucocerebrosidase, leading to the buildup of fatty substances called glycosphingolipids in organs such as the spleen, liver, bone marrow, and lungs. Type 3 Gaucher disease is the chronic neuronopathic form, combining these systemic problems with progressive neurological symptoms that can include difficulty with eye movements, impaired balance and coordination, seizures, and cognitive decline. People with type 3 disease can also experience anemia, thrombocytopenia, hepatosplenomegaly, bone pain, and fatigue that disrupt daily life.

Venglustat is an oral glucosylceramide synthase inhibitor designed to cross the blood-brain barrier and reduce the abnormal accumulation of glycosphingolipids that contributes to both systemic and neurological damage in type 3 Gaucher disease. While enzyme replacement therapies address many organ and hematologic complications, they do not effectively reach the brain, leaving neurological symptoms largely untreated. By targeting the underlying biochemical pathway in both the body and the central nervous system, venglustat aims to slow or modify disease progression rather than simply manage complications.

The designation is based on results from the phase 3 LEAP2MONO study, which found that patients receiving once-daily oral venglustat had statistically significant improvements in neurological function compared with those treated with the enzyme replacement therapy imiglucerase. Investigators assessed outcomes using a global test score that combined measures of balance and coordination with a standardized assessment of memory and cognition; results favored venglustat at 52 weeks.

In the trial, the drug was generally well tolerated. The most common side effects included headache, nausea, splenomegaly, and diarrhea.

Breakthrough Therapy designation is an FDA program intended to expedite the development and review of drugs for serious or life-threatening conditions when early clinical evidence suggests substantial improvement over available therapies. The designation provides more frequent interaction with regulators and access to expedited review pathways but does not replace the need for full evaluation of safety and efficacy before potential approval. Venglustat previously received Fast Track and orphan drug designations for type 3 Gaucher disease, and Sanofi plans to file for approval globally in 2026.

“This regulatory milestone recognizes the significant unmet medical need for people living with type 3 Gaucher disease, particularly those experiencing progressive neurological deterioration,” said Karin Knobe, global head of clinical development for rare diseases at Sanofi. “The positive LEAP2MONO findings are an encouraging step forward in the research and development process, and we will continue collaborating with the FDA to advance this potential treatment option.”