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Targeted and precisely delivered B-cell therapy

Watch the mechanism of action video

This animated video brings the immune system to life with a molecule's eye view of KESIMPTA 

KESIMPTA® (ofatumumab) mechanism of action

KESIMPTA is thought to work by selectively binding to sites on both the small and large extracellular loops of CD20.1

  • KESIMPTA causes CD20+ B cells to be vulnerable to both immediate and delayed B-cell lysis by mechanisms such as complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity1

Bcell Lymph

B cells in the lymph nodes

Preclinical studies showed that SC delivery preferentially targeted B cells in the lymph nodes2-4

Bcell Spleen

B cells in the spleen

SC delivery of KESIMPTA is thought to spare B cells in the spleen to help maintain immune function, based on preclinical evidence5

The precise mechanism by which KESIMPTA exerts its therapeutic effects is unknown.

The clinical relevance of these data is unknown.

Rapid and sustained B-cell depletion

Subcutaneous, targeted, and precisely delivered therapy that provides rapid B-cell depletion6,7

B-cell depletion sustained over the dosing period

This chart shows B-cell depletion sustained over the dosing period.
  • Reduction in B cells was seen as early as 1 week after treatment initiation2

  • B-cell counts remained below LLN for 97% of patients in ASCLEPIOS I and 92% of patients in ASCLEPIOS II from 12 weeks through 120 weeks2

B-cell repletion as early as 6 months after treatment discontinuation2
  • Data from ASCLEPIOS I and II indicate a median time of 24.6 weeks to B-cell recovery (either to LLN or baseline value) post treatment discontinuation

  • Modeling and simulation for B-cell repletion corroborate these data, predicting median time to B-cell recovery of 23 weeks post treatment discontinuation

“I knew I needed to make a change to have a better chance at beating RMS. I’m glad my doctor agreed.” – Kristin: mother, real estate agent, Kesimpta patient.

"When my neurologist provided the data for me for KESIMPTA, it gave me hope."

Kristin: mom, real estate agent, KESIMPTA patient

Actual patient taking KESIMPTA who was compensated for time. Individual results may vary.

LLN, lower limit of normal; MOA, mechanism of action; SC, subcutaneous.


Contraindication: KESIMPTA is contraindicated in patients with active hepatitis B virus (HBV) infection.

Warnings and Precautions

Infections: Serious, including life-threatening or fatal, bacterial, fungal, and new or reactivated viral infections have been observed during and following completion of treatment with anti-CD20 B-cell depleting therapies....


KESIMPTA is indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults...

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References: 1. Gupta IV, Jewell RC. Ofatumumab, the first human anti-CD20 monoclonal antibody for the treatment of B cell hematologic malignancies. Ann NY Acad Sci. 2012;1263(1):43-56. 2. Kesimpta. Prescribing information. Novartis Pharmaceuticals Corp. 3. Huck C, Leppert D, Wegert V, et al. Low-dose subcutaneous anti-CD20 treatment depletes disease relevant B cell subsets and attenuates neuroinflammation. J Neuroimmune Pharmacol. 2019;14(4):709-719. 4. Torres JB, Roodselaar J, Sealey M, et al. Distribution and efficacy of ofatumumab and ocrelizumab in humanized-CD20 mice following subcutaneous or intravenous administration. P2.2.052. Poster presented at: American Academy of Neurology Annual Meeting; May 4-10, 2019; Philadelphia, PA. 5. Theil D, Smith P, Huck C, et al. Imaging mass cytometry and single-cell genomics reveal differential depletion and repletion of B-cell populations following ofatumumab treatment in cynomolgus monkeys. Front lmmunol. 2019;10:1-11. 6. Hauser SL, Bar-Or A, Cohen JA, et al. B-cell depletion and efficacy outcomes with ofatumumab: subgroup analysis from the pooled phase 3 ASCLEPIOS I and II trials. P7.1-013. Poster presented at: American Academy of Neurology Annual Meeting; 2020; Philadelphia, PA. 7. Hauser SL, Bar-Or A, Cohen JA, et al; for the ASCLEPIOS I and ASCLEPIOS II trial groups. Ofatumumab versus teriflunomide in multiple sclerosis. Supplemental appendix. N Engl J Med. 2020;383(6):546-557.