The neurological disease affects approximately 2.8 million people worldwide

Sanofi has reported positive new data from a mid-stage study of its investigational anti-CD40L antibody in patients with relapsing forms of multiple sclerosis (MS).

Results from the phase 2 study, being presented at the 2023 Consortium of Multiple Sclerosis Centers annual meeting, demonstrate that frexalimab significantly reduced disease activity in patients with relapsing forms of the disease.

The study randomised 129 patients to receive either higher or lower doses of frexalimab, or matching placebo, for 12 weeks. After week 12, patients receiving placebo switched to respective frexalimab arms and entered the open-label part B, which is currently ongoing.

Following 12 weeks of therapy, the number of new gadolinium-enhancing T1-lesions was reduced by 89% and 79% in the higher- and lower-dose treatment arms, respectively, compared with placebo, meeting the study’s primary endpoint.

Additionally, both groups treated with frexalimab showed reductions in new or enlarging T2-lesions and total gadolinium-enhancing T1-lesions.

Frexalimab was well-tolerated, the company said, and 97% of patients completed part A and continued to the open-label part B.

Erik Wallström, global head of neurology development at Sanofi, said: "...we are committed to growing our robust pipeline of MS therapies by exploring multiple treatment approaches with unique mechanism of actions that have the potential to slow or halt disability, which remains one of the greatest unmet medical needs in MS today.”

Affecting approximately 2.8 million people worldwide, MS is a disabling, neurological disease in which the immune system attacks the protective myelin sheath that covers the nerves and disrupts communication between the brain and the rest of the body.

Relapsing forms of MS are characterised by clearly defined, but unpredictable, attacks of worsening neurologic function, followed by partial or complete recovery periods. Approximately 85% of patients are initially diagnosed with relapsing forms of MS, compared to 15% with progressive forms of the disease.

"Frexalimab has a unique mechanism of action, blocking the CD40/CD40L costimulatory pathway thought to regulate both adaptive and innate immune cell activation and function – a pathway that is pivotal in the pathogenesis of MS,” explained Gavin Giovannoni, chair of neurology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London.

Following the positive phase 2 results, Sanofi plans to initiate pivotal trials in MS in 2024.