Zenas BioPharma Announces Positive Phase 2 Trial Results for Obexelimab in Relapsing Multiple Sclerosis

Zenas BioPharma, Inc. reported positive results from its Phase 2 MoonStone trial of obexelimab in relapsing multiple sclerosis (RMS). The trial met its primary endpoint, showing a 95% relative reduction in new gadolinium-enhancing T1 lesions compared to placebo, with a p-value of 0.0009. The adjusted mean number of new lesions per scan in the obexelimab group was 0.01, compared to 0.23 in the placebo group. The safety profile of obexelimab was consistent with previous trials, with mild injection site reactions being the most common adverse event. Zenas expects to report 24-week data from the MoonStone trial in the first quarter of 2026, which will include additional secondary and exploratory endpoints. The company also anticipates topline results from the Phase 3 INDIGO trial in IgG4-RD by the end of 2025 and from the Phase 2 SunStone trial in systemic lupus erythematosus in mid-2026.