The US Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to tolebrutinib for the treatment of adults with non-relapsing secondary progressive multiple sclerosis (nrSPMS).
This is based on positive results from the HERCULES phase 3 study, demonstrating that tolebrutinib delayed the time to onset of 6-month confirmed disability progression (CDP), by 31% compared to placebo (HR 0.69; 95% CI 0.55-0.88; p=0.0026), with further analysis of secondary endpoints demonstrating that the number of participants who experienced confirmed disability improvement was nearly double with tolebrutinib (10%) compared to those on placebo (5%) (HR 1.88; 95% CI 1.10 to 3.21; nominal p=0.021).
FDA Breakthrough Therapy designation is designed to expedite the development and review of medicines in the US that target serious or life-threatening conditions. Medicines qualifying for this designation must show preliminary clinical evidence that the drug may demonstrate substantial improvement on clinically significant endpoints over available medicines.
Erik Wallström, MD, PhD, Global Head of Neurology Development, Sanofi, said: “This Breakthrough Therapy designation demonstrates the potential for tolebrutinib to delay disability progression, a critical unmet need for people living with multiple sclerosis. We look forward to working with the FDA during the regulatory review of this first of its kind medicine in non-relapsing secondary progressive multiple sclerosis where there are currently no approved treatments available.”
Liver enzyme elevations (>3xULN) were observed in 4.1% of participants receiving tolebrutinib compared with 1.6% in the placebo group. A small (0.5%) proportion of participants in the tolebrutinib group experienced peak ALT increases of >20xULN, all occurring within the first 90 days of treatment. All but one case of liver enzyme elevations resolved without further medical intervention. The implementation of more frequent monitoring has helped mitigate serious liver sequelae.
Regulatory submissions of tolebrutinib are currently being finalized for the US and prepared for the EU. The PERSEUS phase 3 study in primary progressive MS is currently ongoing with study results anticipated in H2 2025.
