Kesimpta (ofatumumab)

Kesimpta® (ofatumumab) has been approved to treat relapsing forms of multiple sclerosis (RMS) in adults. This includes clinically isolated syndrome, relapsing-remitting disease (RRMS), and active secondary progressive disease. Kesimpta is a subcutaneous (under the skin) injection.1

How is Kesimpta administered?

Kesimpta is a first-line treatment option for people RMS. People with RMS can self-administer the medication with a Sensoready® autoinjector pen. Kesimpta is the first B-cell therapy that can be self-administered at home. Kesimpta studies have shown the drug to be highly effective when administered at home.1

Novartis Pharmaceuticals makes Kesimpta. It is expected to be available in September 2021. The active ingredient in Kesimpta is ofatumumab.1

How does Kesimpta work?

Kesimpta belongs to a class of drugs called monoclonal antibodies. Monoclonal antibodies are proteins that are made in a lab. They act like human antibodies to restore, enhance, or mimic the immune system’s attack on cells.1,2

The exact way Kesimpta works in people with MS is unknown. Doctors think it sticks to the protein CD20 on the surface of B cells. These are cells that play a key role in the body’s immune response. In people with MS, B cells damage nerves in the brain and spinal cord. Kesimpta works to kill these cells, which reduces inflammation and helps slow down nerve damage.1,2

What are the possible side effects of Kesimpta?

The most common side effects of Kesimpta include:1,2

  • Upper respiratory tract infection
  • Headache
  • Injection-relation reaction, such as fever, chills, headache, muscle pain, fatigue. These usually occur during the first 24 hours and after the first injection
  • Local injection site reaction, such as redness, swelling, itching, pain

Other less common side effects include:1,2

  • Urinary tract infection
  • Back pain
  • Lab abnormalities

Contact your doctor right away if you have any signs of infection, such as fever, chills, cough, or painful urination.2

These are not all the possible side effects of Kesimpta. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with Kesimpta.

Things to know about Kesimpta

Kesimpta may reactivate hepatitis B infection. Do not use Kesimpta if you have an active hepatitis B infection. Your doctor will screen you for hepatitis B before prescribing Kesimpta. Your doctor will also screen you for serum immunoglobulins.2

Risk of PML

A rare, life-threatening brain infection known as progressive multifocal leukoencephalopathy (PML) has occurred in people with chronic lymphocytic leukemia (CLL) who have taken Kesimpta. The doses of Kesimpta given to these people for their CLL were higher than the doses for MS. While no cases of PML occurred in Kesimpta clinical trials, this is still a possible risk. If you have any symptoms like weakness, clumsiness, vision problems, confusion, or personality changes, contact your doctor right away.2

Live vaccines

You should not get live vaccines during treatment with Kesimpta and for some time after the last dose. Talk to your doctor option your options for vaccines while taking Kesimpta.2


Kesimpta can harm an unborn baby. Women who can become pregnant should use birth control during treatment and for some time after the last dose of Kesimpta. Women should also not breastfeed during treatment with Kesimpta and for some time after the last dose. Talk to your doctor about your options for birth control and breastfeeding while taking Kesimpta.2

Have your doctor or nurse teach you how to use Kesimpta and how to dispose of syringes and needles.2

Before beginning treatment for multiple sclerosis, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

For more information, read the full prescribing information of Kesimpta.

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Written by: Karen Berger | Last reviewed: March 2021