Section 04 · Monograph
Ofatumumab
Reviewed Nov 2026FDA label
KesimptaAnti-CD20 mAb
- Forms
- SC pen: 20mg
- Dose
- 20mg Wk0,1,2, then 20mg monthly starting Wk4
- MOA
- Depletes CD20+ B-cells
Indications
- Relapsing forms of multiple sclerosis, including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive diseaseFDA-labeled
Mechanism of Action
- Human anti-CD20 monoclonal antibody
- Binds a distinct epitope on CD20 expressed on B lymphocytes
- Induces B-cell lysis via complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, depleting circulating B cells
Full Dosing
Adult / usual
- Initial: 20 mg subcutaneous injection at weeks 0, 1, and 2
- Maintenance: 20 mg subcutaneously once monthly starting at week 4
- Self-administered via prefilled Sensoready pen or syringe after training
Contraindications
- Active hepatitis B virus infection
Drug Interactions
- Avoid live/live-attenuated vaccines during and after treatment until B-cell repletion
- Additive immunosuppression with other immunosuppressive or immune-modulating therapies
Adverse Effects
- Injection-site reactions (erythema, swelling, pruritus)
- Upper respiratory tract infection
- Headache
- Systemic injection-related reactions (fever, myalgia, chills)
- Reduced immunoglobulin levels with long-term use
- Increased infection risk
Monitoring Parameters
- Hepatitis B screening before initiation
- Immunoglobulin levels periodically with long-term therapy
- Signs of infection
- Vaccination status prior to starting treatment
Pregnancy & Lactation
- Limited human data; may cause transient peripheral B-cell depletion in neonates
- Consider pregnancy exposure registry
- Unknown if present in human milk; weigh benefits vs risks