Tolebrutinib Wins EU Approval as First nrSPMS Disability-Targeting Therapy Amid Ongoing US Regulatory Stall

Tolebrutinib Wins EU Approval as First nrSPMS Disability-Targeting Therapy Amid Ongoing US Regulatory Stall

On June 23, 2026, the European Commission approved Sanofi's Cenrifki (tolebrutinib) for the treatment of adult patients with non-relapsing secondary progressive multiple sclerosis (nrSPMS) who have not experienced relapses in the last two years.

This represents an important regulatory milestone: Cenrifki is the first-ever therapy specifically approved to target disease and disability progression in this distinct progressive MS population. However, the approval highlights a growing regulatory divergence between Europe and the United States, where the drug's regulatory path remains stalled.

The Science: Penetrating the Blood-Brain Barrier

Unlike older-generation disease-modifying therapies (DMTs) that target peripheral immune cells, tolebrutinib is an oral, brain-penetrant Bruton's tyrosine kinase (BTK) inhibitor. It is designed to cross the blood-brain barrier to modulate microglial and B-cell signaling directly within the central nervous system (CNS). This mechanism targets "smoldering" neuroinflammation, which drives irreversible axonal injury and disability accumulation in progressive MS, even in the absence of active peripheral inflammatory relapses.

Robust Phase 3 HERCULES Efficacy

The European approval is primarily based on results from the Phase 3 HERCULES trial, which randomized 1,131 patients with nrSPMS (2:1 ratio) to daily tolebrutinib 60 mg or placebo:

• Confirmed Disability Progression (CDP): Tolebrutinib achieved a statistically significant 31% relative risk reduction in 6-month CDP compared with placebo (HR, 0.69; P = .0026).
• Confirmed Disability Improvement: Patients on tolebrutinib were nearly twice as likely to achieve confirmed disability improvement compared to those on placebo (10% vs 5%; HR, 1.88).
• Biomarker Subgroup Benefit: Post-hoc analyses showed a 54% reduction in 6-month disability worsening among patients in the highest quartile of paramagnetic rim lesions (PRLs)—a radiographic marker of chronic active CNS lesions.

Safety and Hepatotoxicity Risk

Tolebrutinib's clinical trials revealed a risk of drug-induced liver injury (DILI). In the HERCULES trial, liver transaminase elevations greater than three times the upper limit of normal (>3x ULN) occurred in 4.1% of tolebrutinib-treated patients compared to 1.6% in the placebo group. Consequently, European prescribing guidelines require strict, regular hepatic monitoring. Sanofi will commercially launch Cenrifki first in Germany, accompanied by a robust Risk Management and Patient Support Program.

The US Regulatory Stall and Divergence

Cenrifki's successful European launch stands in stark contrast to its ongoing uncertainty in the United States:

• FDA Review Extension: In September 2025, the FDA extended its review of Sanofi's NDA for tolebrutinib after a major amendment pushed the PDUFA date to December 28, 2025. This date passed without an approval decision.
• Confirmatory PPMS Trial Failure: In December 2025, the Phase 3 PERSEUS trial evaluating tolebrutinib in primary progressive MS (PPMS) failed to meet its primary endpoint of delaying 6-month composite confirmed disability progression, forcing Sanofi to redact its PPMS regulatory plans.
• Ongoing Stagnation: While European, Australian, and UAE regulators have accepted the HERCULES data as sufficient for nrSPMS approval, the FDA has yet to make a final decision, leaving American nrSPMS patients without any approved disease-modifying treatment¹ targeting underlying disability progression.

"Unlike earlier-generation BTK inhibitors developed for oncology, tolebrutinib crosses the blood-brain barrier, allowing it to inhibit microglial and B-cell signaling within the CNS, where compartmentalized inflammation is thought to sustain irreversible axonal injury in SPMS. This mechanism distinguishes it from existing disease-modifying therapies, most of which target peripheral immune activity with limited effect on progression in the absence of active relapses." — NeurologyLive, June 29, 2026