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What is Arzerra used for and how does it work?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on March 14, 2023.

Official answer


Arzerra (ofatumumab) is approved by the FDA to treat patients with chronic lymphocytic leukemia (CLL), a type of slowly progressing cancer in your blood and bone marrow. In CLL, the white blood cells (lymphocytes) made by your bone marrow are damaged which can lead to an increased risk of infections. It may be used with other cancer treatments.

Specifically, Arzerra is used:

  • in combination with chlorambucil in untreated patients with CLL who cannot use fludarabine-based therapy.
  • in combination with fludarabine and cyclophosphamide for the treatment of patients with CLL that has come back (relapsed).
  • for extended treatment (maintenance) of patients with CLL who have had a complete or partial response after at least two lines of therapy for CLL.
  • for the treatment of patients with CLL who did not respond to previous treatment (refractory) to fludarabine and alemtuzumab.

It is given on various dosing schedules (cycles) as an intravenous (IV) infusion based on your diagnosis.

Arzerra is manufactured by Novartis.

What is the mechanism of action of Arzerra?

Arzerra (ofatumumab) is in a class of medicines known as human monoclonal antibodies.

Arzerra is designed to target (bind to) the CD20 molecule found on the surface of cancerous B cells and normal B lymphocytes. CD20 is a protein commonly found on the surface of cancer cells in patients with chronic lymphocytic leukemia (CLL). Arzerra can kill the cancer cells but may also attack healthy B cells in the body, which can lead to side effects.

In conjunction with the immune system, Arzerra is thought to eliminate the cancerous CD20-positive B cells by two mechanisms: destroying the cancer cell through lysis (complement-dependent cytotoxicity) and by helping to release molecules from immune cells (like NK cells) that can enter and kill the cancer cell (antibody-dependent, cell-mediated cytotoxicity).

These mechanisms kill the cancerous and healthy B cells. However, over time, healthy B cells are developed from blood-forming “stem cells” that reside in the bone marrow and then are released to the blood.

This is not all the information you need to know about Arzerra (ofatumumab) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

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