RedHill Biopharma, Ltd., recently announced the conclusion of the last dosing and patient follow-up visit for its Phase 2a proof-of-concept study to assess the efficacy and safety of the experimental drug RHB-104 as an add-on therapy to interferon beta-1a in patients with relapsing-remitting multiple sclerosis (RRMS).

MS is a demyelinating disease in which the insulating covers (myelin) of the nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to communicate, resulting in a wide range of signs and symptoms.

RRMS is characterized by clearly defined attacks of worsening neurological function. The attacks — called relapses, flare-ups or exacerbations — are followed by partial or complete recovery periods (remissions), during which symptoms improve partially or completely, and there is no apparent disease progression. Approximately 85% of MS patients are initially diagnosed with RRMS, and 10-15% with progressive forms of the disease.

RHB-104 is an antibiotic combination therapy, in oral capsule formulation, with potent anti-mycobacterial, anti-inflammatory, and intracellular properties.

The open label CEASE-MS Phase 2a clinical trial is being conducted in two medical centers in Israel. The 18 patients with RRMS enrolled received treatment with RHB-104 for the full 24 weeks set out in the trial and are currently being assessed for another 24 weeks. The trial’s primary endpoint is the number of unique active lesions, assessed at baseline through week 24. Other outcome measures include the safety and tolerability of the antibiotic therapy, relapse rate, changes in cytokines, Expanded Disability Status Scale (EDSS), and the number of participants with adverse events.

RedHill Biopharma is expecting to announce top-line interim data early in 2016. A full analysis and the final Clinical Study Report (CSR) are anticipated by mid-year.

Clara Fehrmann, RedHill’s director of Clinical Operations, said in a press release: “The completion of the final dosing in the active treatment phase of the Phase IIa CEASE-MS study is an important milestone in RedHill’s RHB-104 development program. Top-line interim results will become available in the coming months and we are hopeful that they will support the hypothesis that RHB-104 may counterbalance a dysregulated immune system which plays a critical role in the pathogenesis of multiple sclerosis.”

Prior to this Phase 2a clinical trial, RedHill conducted several successful preclinical studies which demonstrated that RHB-104 was able to inhibit production of the pro-inflammatory cytokines IL-6 and TNF, supporting the drug use as a potential treatment option for patients with inflammatory conditions in which these specific cytokines play a pathological role.

RHB-104 is also being assessed as a possible treatment for patients with Crohn’s disease.