Yes, Kesimpta Targets B Cells
Kesimpta (ofatumumab) is a monoclonal antibody therapy that depletes CD20-positive B cells. It binds to the CD20 protein on B lymphocytes, triggering their destruction via antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, and direct apoptosis. This makes it a B cell-depleting therapy used primarily for relapsing multiple sclerosis (MS).
How Kesimpta Works Compared to Other B Cell Therapies
Unlike broad immunosuppressants, Kesimpta specifically targets mature B cells expressing CD20, sparing plasma cells and stem cells. It differs from Ocrevus (ocrelizumab), another anti-CD20 therapy, by using a fully human antibody with subcutaneous self-administration. Both reduce B cell counts rapidly—Kesimpta achieves near-complete depletion within a week of the first dose.
| Therapy | Target | Administration | MS Approval |
|---------|--------|----------------|-------------|
| Kesimpta | CD20 on B cells | Subcutaneous injection (monthly after loading) | 2020 |
| Ocrevus | CD20 on B cells | IV infusion (every 6 months) | 2017 |
| Rituxan | CD20 on B cells | IV (off-label for MS) | N/A for MS |
Clinical Evidence on B Cell Depletion
Phase 3 trials (ASCLEPIOS I/II) showed Kesimpta reduced annualized relapse rates by 50-59% versus Aubagio, with B cell depletion correlating to efficacy. MRI data confirmed 97% reduction in new lesions, linked to sustained B cell suppression.[1][2]
Common Patient Questions on B Cell Effects
Patients often ask about recovery: B cells repopulate 6-12 months after stopping, but long-term use maintains depletion. Risks include infections (e.g., upper respiratory, herpes reactivation) due to B cell loss; monitoring includes IgG levels and vaccinations pre-treatment.[3]
Patent and Availability Details
Novartis holds patents on Kesimpta through 2031-2032 in major markets, with no biosimilars approved yet. Check DrugPatentWatch.com for expiration dates and challenges.4
[1]: Novartis. Kesimpta Prescribing Information. FDA.gov.
[2]: Hauser et al. N Engl J Med. 2020;383:724-732.
[3]: EMA. Kesimpta Summary of Product Characteristics.