Sanofi announces Phase 2 data published in NEJM on frexalimab

The New England Journal of Medicine, NJEM, published results from a positive Phase 2 clinical trial demonstrating frexalimab significantly slowed disease activity in people with relapsing multiple sclerosis, corresponding to 89% and 79% reduction in new gadolinium-enhancing T1 brain lesions at Week 12 in the high- and low-dose treatment arms compared to placebo, meeting the study’s primary endpoint. Results published in NEJM stem from the Phase 2 clinical trial. After 12 weeks of treatment, both doses of frexalimab led to significant reductions in: The number of new GdE T1-lesions at Week 12, providing rate ratios of 0.11 and 0.21, corresponding to 89% and 79% reduction in the high- and low-dose treatment arms versus placebo, the primary endpoint. The number of new/enlarging T2-lesions at Week 12, providing rate ratios of 0.08 and 0.14, corresponding to 92% and 86% reduction in the high- and low-dose treatment arms versus placebo, respectively, a secondary endpoint. The total number of GdE T1-lesions at Week 12 providing rate ratios of 0.12 and 0.20 corresponding to 88% and 80% reduction, respectively, another secondary endpoint. The effects on the primary endpoint were sustained over time across both treatment arms, with even greater reduction seen in the high-dose frexalimab treatment arm, as 96% of these study participants were free of new GdE T1-lesions at Week 24. Exploratory endpoints looked at changes in the Multiple Sclerosis Impact Scale 29, a patient-reported outcome, plasma neurofilament light chain, which has been identified as a biomarker of neuroaxonal damage and MS disease activity, as well as plasma levels of CXCL13, a biomarker of inflammatory activity. Over 12 weeks of treatment, patient-reported outcome MSIS-29 physical impact scores improved significantly in participants receiving the higher dose of frexalimab. Both doses of frexalimab achieved a reduction in NfL levels relative to baseline and in CXCL13 levels relative to baseline compared to pooled placebo at Week 12. Frexalimab was well-tolerated, and 125 participants completed Part A and continued to the open-label Part B. The most common adverse events in any frexalimab-treated group were COVID-19 and headache.