Sanofi has announced that its investigational anti-CD40L antibody frexalimab has shown potential as a “high-efficacy therapy" for relapsing multiple sclerosis (MS), according to mid-stage results published in The New England Journal of Medicine.

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.

Sanofi frexalimab has "a unique method of action with the potential to address both acute and chronic neuroinflammation in MS without causing lymphocyte depletion,” the company said.

The phase 2 study of the candidate randomised 129 patients to receive one of two doses of frexalimab or matching placebo. 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 high- and low-dose treatment arms, respectively, versus placebo, meeting the study’s primary endpoint.

The effects on the primary endpoint were sustained over time across both treatment arms, Sanofi said, with an even greater reduction seen in the high-dose frexalimab treatment arm, as 96% of these patients were free of new gadolinium-enhancing T1-lesions at week 24.

Additionally, both groups treated with frexalimab showed significant reductions in the number of new or enlarging T2-lesions and the total number of gadolinium-enhancing T1-lesions at week 12, and 97% of patients completed part A and continued to the open-label part B.

Sanofi outlined that it has initiated phase 3 clinical trials of frexalimab in relapsing MS and non-relapsing secondary progressive MS.

Study author, Patrick Vermersch, University of Lille, CHU Lille, said the results “represent important data in not only the potential treatment of MS but to the broader MS community”.

https://www.pmlive.com/pharma_news/sanofis_investigational_frexalimab_shows_promise_in_relapsing_forms_of_ms_1508503