In the Phase 3 LEAP2MONO study (n=43), venglustat achieved statistically significant improvement in neurological function at week 52 versus enzyme replacement therapy in type 3 Gaucher disease, meeting its primary endpoint across a global score comprising the SARA modified total score and RBANS total index (p=0.007). The trial met three of four key secondary endpoints and matched ERT on systemic measures including spleen and liver volume and hemoglobin. Safety was consistent with prior experience, with headache, nausea, diarrhea, and spleen enlargement among the most common adverse events; no new signals emerged.
Sanofi will file globally for GD3 based on LEAP2MONO, positioning venglustat as a brain-penetrant, once-daily oral option aimed at the neurologic manifestations where ERT has not demonstrated effect. The company also disclosed that PERIDOT, a Phase 3 study in Fabry disease, did not meet its patient-reported primary endpoint, though a second Phase 3 (CARAT) focused on cardiac structural outcomes remains underway. In parallel, Sanofi recently secured a U.S. label expansion for Cerezyme to include non-CNS manifestations of GD3 using real-world evidence, reinforcing its systemic ERT franchise as it advances an oral, CNS-penetrant agent.
Strategically, this is a calculated bid to redefine standard care in neuronopathic GD3 by substituting an oral GCS inhibitor for infusion-based ERT in stabilized patients. LEAP2MONO’s double-dummy design and requirement for prior ERT with systemic targets achieved de-risked the substitution on visceral endpoints and created a clean head-to-head on neurologic outcomes—precisely where regulators have sought evidence and where payers will scrutinize differentiation. The Fabry miss tempers any assumption of class portability across lysosomal indications and shifts the near-term value driver squarely to GD3; CARAT’s cardiac readout becomes pivotal for whether the platform extends beyond Gaucher.
For sites and CROs, the GD3 pathway underscores the operational premium on standardized neurologic assessments and rater training across small, globally distributed cohorts. Expect renewed emphasis on instrument fidelity for SARA and RBANS and tighter data surveillance around intra-rater variability. If approved, an oral alternative could reduce infusion center dependency for eligible GD3 patients and may rebalance site portfolios toward neurology-capable centers. For sponsors and tech vendors, LEAP2MONO illustrates how small, well-controlled rare disease studies can meet regulatory expectations when anchored to clinically salient, regulator-accepted functional endpoints, with biomarker data as supportive rather than determinative. Regulators will weigh a first-in-class CNS benefit in a high-need population against the limited sample size and the outstanding key secondary endpoint not met—likely platelet count—alongside pending CSF and plasma substrate biomarker analyses.
The immediate watch items are durability and trajectory: whether neurologic gains persist or deepen in the ongoing open-label phase, how biomarkers (GL1 and lyso-GL1) track with function, and whether systemic parity holds beyond 52 weeks in patients transitioned off ERT. Review dynamics at FDA and EMA will signal how comfortable agencies are with monotherapy substitution on the basis of a 43-patient study and a composite neurologic endpoint. On the commercial and operations side, clarity on pediatric labeling, potential requirement for prior ERT stabilization, and any risk management around splenic events will shape uptake and site workflows. Beyond Gaucher, CARAT will determine whether the brain-penetrant GCSi strategy can deliver organ-level outcomes in Fabry; a second negative Phase 3 would confine venglustat’s impact to GD3 and reframe portfolio strategy around selective indications where CNS penetration confers a clear clinical edge.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
