Multi-Center, Randomized, Double-Blinded Phase 3 Study to Evaluate the Efficacy, Safety, and Tolerability of IMU-838 versus Placebo in Adults with Relapsing Multiple Sclerosis (ENSURE-1)

This study will be a multicenter, randomized, double-blind, placebo-controlled study with a blinded Main Treatment Period (MT) and an Open Label Period (OLE) to evaluate the efficacy, safety, and tolerability of IMU-838 in adult patients with RMS. The study will consist of the following periods:

Screening Period: Approximately 28 days Main Treatment Period: Up to 72 weeks (approximately 15 months) Open Label Extension Period: Up to approximately 8 years

Inclusion Criteria:

• Male or female patient (age ≥18 to ≤55 years).

• Patients with an established diagnosis of MS according to 2017 McDonald Criteria.

• Patients with RMS comprising of relapsing remitting MS (RRMS) and active secondary progressive MS, both defined according to Lublin criteria 1996 and 2014.

• Active disease as defined by Lublin 2014 evidenced prior to Screening by:

  1. At least 2 relapses in the last 24 months before randomization, or
  2. At least 1 relapse in the last 12 months before randomization, or
  3. A positive Gd+ MRI scan (brain and/or spine) in the last 12 months prior to randomization.

• Willingness and ability to comply with the protocol.

• Written informed consent given prior to any study-related procedure.

Exclusion Criteria:

• Patients with non-active secondary progressive MS and primary progressive MS.
• Any disease other than MS that may better explain the signs and symptoms, including history of complete transverse myelitis.
• Clinical signs or presence of laboratory findings suggestive for neuromyelitis optica (NMO) spectrum disorders or myelin oligodendrocyte glycoprotein (MOG)-IgG-associated encephalomyelitis
• Any active and uncontrolled coexisting autoimmune disease, other than MS (except for type 1 diabetes mellitus and inflammatory bowel disease)
• Use of experimental/investigational drug (with the exception ofCOVID-19 vaccines approved by emergency use authorization) and/or participation in drug clinical studies within 6 months prior to Screening
• Previous or current use of MS treatments lifelong, or within a pre-specified time period.
• Use of the pre-specified concomitant medications.
• Clinically significantly abnormal and pre-specified lab values.
• History of chronic systemic infections within 6 months before the date of informed consent.
• Diagnosis or suspected liver function impairment, which may cause fluctuating liver function tests during this study.
• Known history of nephrolithiasis or underlying condition with a strong association of nephrolithiasis.
• History or clinical diagnosis of gout.
• History or presence of any major medical or psychiatric illness
• Substantial medical condition that could create undue risk to the patient, could affect adherence with the study protocol or could undesirably affect study outcomes