Kesimpta (ofatumumab)

Kesimpta (ofatumumab) is a disease modifying drug (DMD) for relapsing remitting MS.

You take Kesimpta as an injection under the skin once a month. It reduces the number of relapses by about two thirds (70%).

Common side effects include injection site reactions, injection-related reactions, head colds, chest infections and urinary tract infections.

What is Kesimpta used for in MS?

Kesimpta is a disease modifying drug (DMD) for active relapsing remitting and very active relapsing remitting MS. You have fewer relapses than you might have had without treatment and any relapses you do have should be less severe. Disease progression is slowed.

Kesimpta is a highly effective (category 2.0) DMD; in clinical trials, people taking Kesimpta had 50-59% fewer relapses than people taking Aubagio. In clinical trials, MRI scans showed that people taking Kesimpta had fewer, smaller or no new areas of active MS (lesions). Kesimpta also slowed down the build-up of disability associated with MS.

Who can take Kesimpta?

Kesimpta can be prescribed for adults with active relapsing remitting MS and very active relapsing remitting MS.

Kesimpta has been approved for use on the NHS since 2021. It can only be prescribed by a neurologist.


It’s important that you tell your MS team if you have any health problems or are taking other medicines.  Kesimpta may not be appropriate if you have existing medical conditions including cancer, a serious infection such as hepatitis B, severe problems with your immune system or are taking other medicines which suppress the immune system.

Conception and pregnancy

Pregnancy is not recommended during treatment with Kesimpta. If you plan to start a family discuss your specific circumstances with your MS team.

Women of child-bearing age must use an effective method of contraception during treatment and for 6 months after stopping Kesimpta.

If you become pregnant while taking Kesimpta, contact your neurologist or MS nurse. This is because Kesimpta can reduce the number of immune cells (B cells) in both the mother and unborn baby.

How do I take Kesimpta?

You self-inject Kesimpta under the skin (subcutaneous) once a month. Kesimpta is supplied as a ready-filled automatic injection pen.

You start treatment with one dose per week for the first three weeks (week 0, week 1 and week 2) and then you skip a week (week 3). After that you move on to one dose per month starting at week 4.

Your MS nurse will show you how to do the injections, discuss the practicalities and offer advice or training and ongoing support if you should need it.

My experiences with Kesimpta

I like having the control of doing the injections myself, it is quick and easy and I am well supported by both my GP surgery and MS team. 

Person with MS

Read the personal story: My experiences with Kesimpta (ofatumumab)

What side effects could I get with Kesimpta?


Common side effects include:

  • injection-site reactions, such as redness, pain, itching and swelling at the injection site
  • injection-related reactions, such as fever, headache, muscle pain, chills and tiredness

Most people treated with Kesimpta experience injection-site reactions or injection-related reactions. These are generally mild to moderate and clear-up the same or following day. They are mostly associated with the first injection and less frequent with subsequent injections.

  • infections including coughs, colds, chest infections and cold sores (oral herpes)

Kesimpta suppresses part of the immune system so you will be more vulnerable to infections such as colds and viruses. Your MS team should give advice on ways to minimise the risk of infections.

Common side effects (affecting more than 1 person in 100)

  • injection-site reactions (redness, pain, itching, and swelling)
  • injection-related reactions (fever, headache, muscle pain, chills and tiredness)
  • head colds
  • chest infections
  • urinary tract infections
  • cold sores (oral herpes)
  • decreased blood levels of immunoglobulins which help protect against infection

A full list of side effects is included in the manufacturer's Patient Information Leaflet.

Assessment before treatment

Before starting Kesimpta, you will have tests to check for hepatitis B. Your white blood cell levels may also be checked. Your doctor will check if you need any vaccinations before you start treatment with Kesimpta. If you need a live or live-attenuated vaccine it should be given at least 4 weeks before you start Kesimpta. Other types of vaccines should be given at least 2 weeks before you start Kesimpta.

Assessment during treatment

There is no need for routine tests during treatment, but your MS nurse will arrange regular appointments to check how you are coping with Kesimpta.

How does Kesimpta work?

Kesimpta is a monoclonal antibody, a type of drug developed to attack specific targets in the immune system.

Kesimpta has been designed to target a particular marker (CD20) on the surface of B cells, a type of white blood cell (lymphocyte) which is thought to be involved when the immune system attacks the myelin around nerve cells. The targeted B cells are destroyed.

Kesimpta research

Evidence for the effectiveness of Kesimpta has come from two large studies:

ASCLEPIOS I and II - Kesimpta compared to Aubagio (teriflunomide) (2020)

These studies recruited 1,882 people with relapsing MS. Participants took either Kesimpta every four weeks or Aubagio (teriflunomide) once daily for an average of 1.6 years. Compared to Aubagio, Kesimpta reduced the number of relapses by 50-59%. Kesimpta also significantly reduced the number or people experiencing a worsening of disability which lasted for 3 months and 6 months by 32-34%.

Find out more

National Institute for Health and Care Excellence (NICE)
Ofatumumab for treating relapsing multiple sclerosis
NICE technology appraisal guidance TA699
Full guideline (link is external)
Scottish Medicines Consortium (SMC)
Ofatumumab (Kesimpta)
SMC 2357
Full guideline (link is external)
Hauser SL, et al.
Ofatumumab versus teriflunomide in multiple sclerosis.
New England Journal of Medicine 2020; 383:546-57
Full article (link is external)
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