Tolebrutinib in Nonrelapsing Secondary Progressive Multiple Sclerosis.

Area of Science:

• Neuroscience
• Immunology
• Pharmacology

Background:

• Multiple sclerosis (MS) can lead to progressive neurological impairment known as disability accrual.
• Current MS therapies have limited efficacy against non-relapse-associated disability accrual, often driven by chronic neuroinflammation.
• Tolebrutinib, an oral Bruton's tyrosine kinase inhibitor, targets myeloid cells and B cells, addressing central nervous system inflammation.

Purpose of the Study:

• To evaluate the efficacy of tolebrutinib in patients with nonrelapsing secondary progressive multiple sclerosis (SPMS).
• To assess the impact of tolebrutinib on confirmed disability progression in SPMS.
• To determine the safety and tolerability of tolebrutinib in this patient population.

Main Methods:

• A Phase 3, double-blind, placebo-controlled, event-driven trial.
• 1131 participants with nonrelapsing SPMS were randomized 2:1 to receive tolebrutinib (60 mg daily) or placebo.
• Primary endpoint: confirmed disability progression sustained for at least 6 months, analyzed by time-to-event.

Main Results:

• Tolebrutinib significantly reduced the risk of confirmed disability progression (22.6% vs. 30.7%; HR 0.69; P=0.003).
• Median follow-up was 133 weeks.
• Serious adverse events were higher in the tolebrutinib group (15.0% vs. 10.4%), as were elevations in alanine aminotransferase levels (4.0% vs. 1.6%).

Conclusions:

• Tolebrutinib demonstrated a reduced risk of disability progression in patients with nonrelapsing SPMS compared to placebo.
• The findings suggest tolebrutinib as a potential new therapeutic option for nonrelapsing SPMS.
• Further monitoring for adverse events, particularly liver enzyme elevations, is warranted.