How it is administered

Ofatumumab is administered as an intravenous (IV) infusion. It comes in a liquid form that is diluted and given through a vein, typically in a hospital or clinic setting where you can be closely monitored. The dosing schedule and amount may vary depending on your treatment plan and the condition being treated. For chronic lymphocytic leukemia (CLL), it is often given in cycles, with the first dose being smaller and subsequent doses larger, spaced weeks apart.

Premedication with acetaminophen, antihistamines, and corticosteroids is recommended before each infusion to help reduce the risk of infusion-related reactions.

How it works

Ofatumumab is a type of medicine called a monoclonal antibody. It works by targeting a protein called CD20, which is found on the surface of certain B cells (a type of white blood cell). By binding to this protein, ofatumumab helps your immune system find and destroy these B cells.

The destruction of B cells is important in blood cancers like chronic lymphocytic leukemia (CLL), because these cancers often involve abnormal B cells that grow uncontrollably. Ofatumumab can help reduce the number of these cancerous cells, slow disease progression, and improve symptoms. The medicine works through two main mechanisms: complement-dependent cytotoxicity (activating a part of the immune system called complement to kill the cells) and antibody-dependent cell-mediated cytotoxicity (recruiting other immune cells to attack the B cells).

Who Should take it

Ofatumumab is approved for adults with chronic lymphocytic leukemia (CLL). It may be used:

• In combination with other chemotherapy medicines (like chlorambucil, fludarabine, or cyclophosphamide) for patients who have not been treated before or whose disease has come back (relapsed CLL).
• For patients who have not responded to other treatments (refractory CLL).
• For extended treatment in patients who have responded to at least two prior therapies for CLL.

While ofatumumab is not specifically approved for Waldenström's Macroglobulinemia, it works on a similar target (CD20) and may be considered in some cases of blood cancers involving B cells, but always under the guidance of a hematologist.

Who should not take it

Ofatumumab should not be used in patients who have had a severe allergic reaction (anaphylaxis) to ofatumumab or any of its ingredients.

Caution is also needed in patients with active infections, particularly hepatitis B, as ofatumumab can cause reactivation of hepatitis B virus, which may be serious or even fatal. All patients should be screened for hepatitis B before starting treatment. If you have a history of hepatitis B or other serious infections, discuss this with your doctor before starting ofatumumab.

Live viral vaccines should not be given during or shortly after treatment with ofatumumab, as your immune system may be weakened.

Commonly used with

Ofatumumab is commonly used in combination with other chemotherapy medicines, such as:

• Chlorambucil
• Fludarabine
• Cyclophosphamide

These combinations are chosen based on your specific type of blood cancer, previous treatments, and overall health.

Commonly tested with

Ofatumumab has been tested in clinical trials with other chemotherapy agents, including:

• Chlorambucil (for previously untreated CLL)
• Fludarabine and cyclophosphamide (for relapsed CLL)

It has also been studied as a single agent for patients with refractory CLL. Your doctor will decide the best combination for you based on your medical history and disease characteristics.