Zenas Biopharma reported a midstage (MoonStone) trial result showing a ~95% reduction in new Gd‑enhancing brain lesions at Weeks 8–12 with obexelimab versus placebo in relapsing multiple sclerosis. The bifunctional monoclonal antibody achieved near‑complete lesion suppression and delivered a safety profile consistent with prior data, the company said. Investors pushed Zenas shares higher on the readout; the result validates the drug’s B‑cell directed mechanism and supports ongoing development programs across autoimmune indications. Zenas plans to report 24‑week data that will include additional secondary and exploratory endpoints relevant to disability and longer‑term outcomes. Obexelimab’s subcutaneous formulation and self‑administration profile were highlighted as pragmatic advantages if later‑stage trials confirm clinical benefit and durability.