NCT06564311

A Study of Obexelimab in Patients With Relapsing Multiple Sclerosis (MoonStone)

A Phase 2, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of Obexelimab in Patients With Relapsing Multiple Sclerosis

• Status: Active Not Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 93 (estimated)
• Sponsor: Zenas BioPharma (USA), LLC · Industry
• Sex: All
• Age: 18 Years – 60 Years
• Healthy volunteers: Not accepted

Summary

This study aims to examine the efficacy and safety of obexelimab in participants with relapsing multiple sclerosis

Detailed description

The study consists of a Screening Period (Day -28 to Day -1), a 24-week treatment period (Part A and Part B), a 52 week open label extension and an expected 12-week Follow-up Period. Patients with Relapsing Multiple Sclerosis will be randomized in 2:1 ratio to obexelimab or placebo. Randomization will be stratified by Gd lesion status at screening (≥ 1 vs 0). Part A is the 12-week Randomized Placebo-Controlled Period (RCP), during which obexelimab or placebo will be administered as weekly subcutaneous (SC) injections. Following Part A, all patients will enter the Part B, a 12-week Open-Label Period (OLP), during which all patients will receive obexelimab administered as weekly SC injections. After Part B, patients will enter Part C, a 52-week Open-Label Extension (OLE), after which they will return for an in-clinic Safety Follow-Up Visit 12 weeks after the completion of Part C (i.e. Week 88). If at this time, B cells have not returned to baseline or above the lower limit of normal (LLN), patients will be asked to return every 12 weeks until B cells return to baseline or above the LLN (at minimum). The maximum expected duration of the study is 92 weeks (Screening Period = 4 weeks, Parts A, B and C = 76 weeks, Follow-up Period = 12 weeks).

Conditions

• Relapsing Multiple Sclerosis

Interventions

Type	Name	Description
DRUG	Obexelimab	Obexelimab is a monoclonal antibody that simultaneously binds CD19 and FcyRIIb, resulting in down regulation of B cell activity
DRUG	Placebo	Placebo

Timeline

• Start date: 2024-08-26
• Primary completion: 2025-08-28
• Completion: 2026-02-01
• First posted: 2024-08-21
• Last updated: 2025-11-17

Locations

47 sites across 12 countries: United States, Austria, Belgium, China, Croatia, Czechia, Denmark, Greece, Italy, Poland, Spain, United Kingdom

Regulatory

• FDA-regulated drug study