Sanofi’s CD40L investigational monoclonal antibody frexalimab has been shown in a mid-stage study to reduce a key biomarker associated with multiple sclerosis (MS) nerve cell damage in patients with relapsing forms of the neurological disease.
Affecting approximately 2.9 million people worldwide, MS occurs when the immune system attacks the protective myelin sheath that covers the nerves and disrupts communication between the brain and the rest of the body.
About 85% of patients are initially diagnosed with relapsing MS, which is characterised by attacks of worsening neurologic function, followed by partial or complete recovery periods.
Sanofi outlined that frexalimab “has the potential to address both acute and chronic neuroinflammation in MS without causing lymphocyte depletion”.
The phase 2 study randomised 129 patients to receive one of two doses of the candidate or matching placebo for 12 weeks, after which 97% of patients entered the open-label extension and 87% remained in the study by the 48-week cut-off.
Results showed a significant reduction in plasma levels of neurofilament light chain (NfL) after one year of treatment.
Patients receiving high-dose frexalimab experienced a 41% reduction in plasma NfL levels from baseline to week 48, while those being treated with a low dose of the drug experienced a 35% reduction.
Additionally, those in the placebo-high group who switched to high-dose frexalimab at week 12 experienced a 24% reduction in plasma NfL levels from baseline to week 48 and a 39% reduction from week 12, while those in the placebo-low group who switched to low-dose frexalimab experienced a 33% reduction from baseline to week 48 and a 39% reduction from week 12.
Erik Wallström, global head of neurology development at Sanofi, said: “People with MS need new high-efficacy treatment options that target disability progression, which remains an unmet need.
“These results, alongside the previously reported phase 2 efficacy and safety results, further show that frexalimab’s novel mechanism of action has the potential to deliver meaningful improvements for people living with this chronic and debilitating disease.”
The company has already initiated phase 3 clinical trials of frexalimab in relapsing MS and non-relapsing secondary progressive MS.