Evobrutinib, also called M2951, is an investigational oral medication to treat relapsing multiple sclerosis (MS), which includes relapsing-remitting MS (RRMS) and active secondary progressive MS (SPMS). Merck KGaA (known as EMD Serono in the U.S. and Canada) is developing the treatment.

How does evobrutinib work?

MS is a neurodegenerative autoimmune condition in which the immune system produces autoantibodies that mistakenly attack the myelin sheath that surrounds and protects nerve cells. The myelin sheath insulates nerve cells and facilitates their proper functioning. The breakdown of the myelin sheath, also known as demyelination, results in brain lesions and leads to the symptoms of MS.

Immune cells such as T- and B-cells play an important role in driving inflammation and the progression of MS.

Bruton’s tyrosine kinase (BTK) is a protein present on several immune cells, such as B-cells, macrophages, and monocytes, that are important for inflammation. BTK plays a vital role in B-cell activation, development, multiplication, and function. B-cells can activate T-cells and further enhance the inflammatory process that damages the myelin sheath.

Evobrutinib is a BTK inhibitor. It blocks the BTK protein and prevents the activation and function of B-cells and subsequently curbs T-cell function and inflammation. Thus, by blocking BTK protein, researchers hope that evobrutinib can reduce the nerve cell damage seen in MS patients, and prevent relapses.

Evobrutinib in clinical trials

A placebo-controlled Phase 2 clinical trial (NCT02975349) compared the efficacy and safety of evobrutinib to that of Tecfidera, an MS treatment that the U.S. Food and Drug Administration (FDA) approved as a treatment to reduce the activation of the immune system. Researchers randomly assigned 267 patients to receive Tecfidera, a placebo, or three different doses of evobrutinib (25 mg once daily, 75 mg once daily, or 75 mg twice daily). Researchers reported no relapses in 79% of patients who received the highest treatment dose. The study also reported reduced brain lesions in MS patients after 24 weeks of treatment. This was maintained through 48 weeks of treatment.

Two ongoing Phase 3 studies — EVOLUTION RMS1 (NCT04032158 ) and EVOLUTION RMS2 (NCT04032171) — are comparing evobrutinib with Avonex, by Biogen. Avonex is a formulation of interferon beta-1a approved to treat MS. Each study plans to enroll a total of 950 RRMS patients. Researchers will randomize the participants to receive evobrutinib or Avonex. The primary objective of the studies is to measure the annual relapse rate. The secondary goals include measuring disability progression and the formation of new brain lesions. Researchers expect to complete EVOLUTION RMS2 by June 2023, and EVOLUTION RMS1 by October 2026.

Other information

Researchers also studying evobrutinib as a potential treatment for other autoimmune conditions such as systemic lupus erythematosus and rheumatoid arthritis.


Last updated: May 28, 2020


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