Zenas BioPharma reported that its Phase 2 MoonStone trial of obexelimab met the primary endpoint in patients with relapsing multiple sclerosis, achieving a 95% relative reduction in new gadolinium‑enhancing T1 lesions versus placebo (p = 0.0009).
The 12‑week, double‑blind, placebo‑controlled study enrolled 116 patients and showed near‑complete suppression of new lesions by week 8, with an adjusted mean of 0.01 new lesions per scan in the obexelimab group compared with 0.23 in the placebo group, and sustained efficacy through week 12. The reduction also extended to new or enlarging T2‑weighted lesions, indicating a broad impact on disease burden.
Obexelimab is a bifunctional humanized monoclonal antibody that targets CD19 on B cells while engaging the inhibitory receptor FcγRIIb, thereby dampening B‑cell activity without depleting B cells. The drug was in‑licensed by Zenas from Xencor in 2021.
Safety data were consistent with prior studies, with only mild injection‑site reactions and a low incidence of infections or hypersensitivity events, underscoring the favorable tolerability profile of the subcutaneous, self‑administered antibody.
Zenas expects to report the 24‑week MoonStone data in the first quarter of 2026, which will include secondary and exploratory endpoints to assess disability progression. The company is also advancing obexelimab in a Phase 3 trial for IgG4‑related disease and a Phase 2 trial for systemic lupus erythematosus.
In addition to obexelimab, Zenas is developing orelabrutinib, a BTK inhibitor, in Phase 3 trials for primary progressive multiple sclerosis and a planned Phase 3 trial for secondary progressive multiple sclerosis in Q1 2026. The company recently secured a $75 million royalty financing from Royalty Pharma and a $120 million private placement, reinforcing its financial position.
Following the announcement, Zenas BioPharma’s shares surged, reflecting investor confidence in the trial results and the company’s broader pipeline.
The content on BeyondSPX is for informational purposes only and should not be construed as financial or investment advice. We are not financial advisors. Consult with a qualified professional before making any investment decisions. Any actions you take based on information from this site are solely at your own risk.