Sanofi’s Tolebrutinib Shows Mixed Results in Phase 3 MS Trials, Plans for FDA Filing Remain

Mixed Trial Results:
Tolebrutinib, Sanofi's experimental drug for multiple sclerosis (MS), failed to meet its primary endpoint in two out of three Phase 3 trials (GEMINI 1 and 2) aimed at reducing annualized relapse rates in relapsing forms of MS.

Success in HERCULES Trial:
However, tolebrutinib met its primary endpoint in the HERCULES Phase 3 trial by delaying the onset of confirmed disability progression in patients with non-relapsing secondary progressive MS (nrSPMS), a form of MS with significant unmet medical need.

Mechanism of Action:
Tolebrutinib is a Bruton’s tyrosine kinase (BTK) inhibitor, which modulates B-cells and microglia associated with MS disease progression.

Liver Safety Concerns:
Despite previous concerns about liver toxicity, preliminary analysis of liver safety in the HERCULES trial was consistent with earlier studies.

Regulatory Plans:
Sanofi plans to discuss these findings with regulatory bodies and aims to submit for approval by the end of 2024.

Market Context:
The success in the HERCULES trial is crucial for Sanofi, as it seeks to compensate for revenue declines following the patent expiration of its existing MS drug, Aubagio.