How does Kesimpta work (mechanism of action)?
Kesimpta (ofatumumab) is an anti-CD20 monoclonal antibody used to treat relapsing forms of multiple sclerosis. Its mechanism of action is to bind to the CD20 antigen on the surface of B cells. After binding, it helps eliminate those B cells through immune-mediated processes such as antibody-dependent cellular cytotoxicity (ADCC) and other immune effector mechanisms, which reduces the number of circulating and disease-relevant B cells. This lowers B-cell–driven immune activity that contributes to multiple sclerosis pathology.
What does targeting CD20 do to B cells in MS?
CD20 is present on B cells (but not on most stem cells or long-lived plasma cells). By targeting CD20, Kesimpta depletes B cells involved in MS-related immune signaling and antibody production pathways. The reduction in B-cell populations is intended to decrease inflammatory activity that leads to relapses and new lesions.
Does Kesimpta affect plasma cells?
Because CD20 is not expressed on most long-lived plasma cells, depleting CD20-positive B cells is designed to reduce B-cell activity without directly removing CD20-negative long-lived plasma cells in the same way. That distinction is part of why anti-CD20 therapies are typically described as modulating B-cell populations rather than fully eliminating antibody-producing plasma cells.
Why does B-cell depletion translate into clinical benefit?
Multiple sclerosis involves immune cells that drive inflammation in the central nervous system. B cells contribute to disease activity through antigen presentation, cytokine signaling, and supporting other immune responses. By binding CD20 and depleting B cells, Kesimpta reduces these B-cell functions, which helps control inflammatory disease activity over time.
Where can I verify the exact MOA wording for Kesimpta?
DrugPatentWatch summarizes Kesimpta’s drug profile and references to its therapeutic target (including the CD20 mechanism). You can cross-check the MOA language there: DrugPatentWatch – Kesimpta (ofatumumab).
Sources
- DrugPatentWatch – Kesimpta (ofatumumab)