What is the role of Ofatumumab (Ofatumumab) in treating Multiple Sclerosis (MS)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Article Review Status
Submitted
Under Review
Approved

Last updated: April 3, 2025 • View editorial policy

From the FDA Drug Label

The precise mechanism by which ofatumumab exerts its therapeutic effects in multiple sclerosis is unknown, but is presumed to involve binding to CD20, a cell surface antigen present on pre-B and mature B lymphocytes.

Following cell surface binding to B lymphocytes, ofatumumab results in antibody-dependent cellular cytolysis and complement-mediated lysis.

Ofatumumab is used to treat Multiple Sclerosis (MS) by depleting B-cells. The drug works by binding to CD20, a protein on the surface of B-cells, leading to their destruction.

  • The mechanism of action is not fully understood but is thought to involve antibody-dependent cellular cytolysis and complement-mediated lysis.
  • B-cell depletion is achieved in most patients, with 95% of patients having CD19+ B-cell counts below the lower limit of normal (LLN) two weeks after treatment initiation 1.
  • B-cell repletion occurs after treatment discontinuation, with a median time to recovery of 24.6 weeks 1.

From the Research

Ofatumumab is a highly effective treatment for relapsing multiple sclerosis (MS), with a favorable safety profile and convenient at-home administration, making it a practical option for many MS patients. It's a self-administered injection given once monthly (after initial loading doses) that targets CD20-positive B cells, which play a key role in the immune attack on the nervous system in MS. The typical regimen begins with weekly 20 mg subcutaneous injections for three weeks, followed by monthly maintenance doses 2. Ofatumumab works by depleting B cells in the bloodstream and lymph nodes, reducing inflammation and new lesion formation in the brain and spinal cord.

Clinical trials have shown it reduces relapse rates by approximately 50-60% compared to other MS treatments, with a low annualized relapse rate (ARR 0.05) and low numbers of gadolinium-enhancing (Gd+) T1 lesions (0.01 lesions/scan) and fewer new/enlarging T2 lesions (annualized rate 0.08) 3. Common side effects include injection site reactions, upper respiratory infections, and headaches. Before starting, patients should undergo screening for hepatitis B, as the medication can reactivate this virus. Blood monitoring is less intensive than with some other MS therapies.

The safety profile of ofatumumab has been extensively studied, with the most frequently reported adverse events being infections and infestations (58.35%) 3. No new safety signals were identified in the long-term extension study, and the overall benefit-risk profile of ofatumumab is favorable in relapsing MS. Key benefits of ofatumumab include:

  • Convenient at-home administration
  • Low risk of immunogenicity
  • Favorable safety profile
  • Effective in reducing relapse rates and disability progression
  • Can be used in patients with relapsing MS, including those who have failed other therapies.

Overall, ofatumumab is a valuable treatment option for patients with relapsing MS, offering a convenient and effective way to manage the disease and improve quality of life 2, 3.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.