Progress and setbacks in Alzheimer’s disease, ALS and psychiatry have dominated most of the newsflow in neuroscience over the past two years. 

However, a positive data readout for Sanofi’s frexalimab may revive interest in the multiple sclerosis pipeline.

Frexalimab, an anti-CD40L antibody, met its primary endpoint in a Phase 2 trial involving 129 patients with relapsing MS, the French drugmaker said Wednesday. At the three-month mark, patients taking the drug saw 89% fewer T1 brain lesions, as seen with gadolinium-enhanced (GdE) MRI, than those taking placebo. 

A lower-dose treatment arm rang up a 79% reduction compared with placebo. Based on the results, Sanofi said it plans to initiate pivotal trials in MS in early 2024.

Finding treatment approaches with unique MOAs that have the potential to slow or halt disability “remains one of the greatest unmet medical needs in multiple sclerosis today,” stated Erik Wallström, the French drugmaker’s global head of neurology development.

Frexalimab, according to Sanofi, is the first so-called second-generation anti-CD40L antibody to show efficacy in the disease. The treatment is thought to work by blocking the CD40/CD40L cellular pathway, which is pivotal to the way the disease manifests.  

In the trial, patients were randomized to receive either higher or lower doses of frexalimab or matching placebo. In addition to the 12-week reductions in total GdE T1-lesions, both groups treated with frexalimab showed decreases in new or enlarging T2-lesions. 

At week 24, 96% of participants in the higher-dose frexalimab arm were free of new GdE T1-lesions, Sanofi said, and the drug was well-tolerated. The open-label Part B, which includes patients in the placebo cohort who have since been switched to respective frexalimab arms, is currently ongoing. 

Sanofi licensed frexalimab, originally dubbed SAR441344, from ImmuNext, a small biotech based in New Hampshire. The antibody is in Phase 2 clinical trials for primary Sjögren’s syndrome and systemic lupus erythematosus, also in collaboration with Sanofi.

The positive MS study was the latest successful clinical data readout for Sanofi. Earlier this month, a Phase 3b trial involving its respiratory syncytial virus (RSV) vaccine showed an 83% reduction in RSV-related infant hospitalizations. The Food and Drug Administration is set to decide on the shot later this year.

Also this month, the drugmaker prevailed in a patent case against Amgen that went all the way to the Supreme Court. The high court rejected Amgen’s appeal of a lower court’s ruling that Sanofi’s PCSK9-inhibiting cholesterol drug, Praluent, did not violate additional patents filed by Amgen for its PCSK9 rival, Repatha.