How it is administered

Ofatumumab is administered as an intravenous (IV) infusion. It is supplied as a clear, colorless, preservative-free liquid concentrate for IV use. The medication is diluted in a saline solution and infused slowly into a vein, typically in a hospital or clinic setting where you can be closely monitored.

The dosing schedule depends on the specific condition being treated and may involve an initial lower dose followed by higher doses at regular intervals. For blood cancers like chronic lymphocytic leukemia (CLL), it is often given in cycles, with the first dose being 300 mg, followed by 1,000 mg doses on specific days. Pre-medication with acetaminophen, antihistamines, and corticosteroids is recommended to reduce the risk of infusion reactions.

How it works

Ofatumumab is a monoclonal antibody that targets a protein called CD20, which is found on the surface of B-cells (a type of white blood cell). By binding to CD20, ofatumumab helps the immune system recognize and destroy these B-cells, including cancerous B-cells found in certain blood cancers.

Once attached, ofatumumab triggers the destruction of B-cells through two main mechanisms: complement-dependent cytotoxicity (which activates a part of the immune system called the complement system to kill the cell) and antibody-dependent cell-mediated cytotoxicity (which attracts other immune cells to attack and kill the targeted B-cell). This leads to a reduction in the number of abnormal B-cells, helping to control the disease.

The depletion of B-cells can be profound and sustained, which is why monitoring and supportive care are important during treatment.

Who Should take it

Ofatumumab is indicated for adults with certain types of blood cancers, particularly chronic lymphocytic leukemia (CLL). It may be used:

• In combination with other chemotherapy drugs (like chlorambucil, fludarabine, or cyclophosphamide) for patients with previously untreated or relapsed CLL.
• As a single agent for patients with CLL who have not responded to other treatments (refractory CLL).
• For extended treatment in patients who have responded to prior therapy for recurrent or progressive CLL.

Ofatumumab may be considered when other standard treatments are not appropriate or have not been effective. The decision to use this medication should be made by your healthcare provider based on your specific diagnosis, overall health, and treatment history.

Who should not take it

Ofatumumab should not be used in patients with a known hypersensitivity to the drug or any of its components. While there are no absolute contraindications listed, caution is advised in certain situations:

• Patients with active hepatitis B infection should not receive ofatumumab due to the risk of reactivation and potentially severe liver problems.
• Patients with severe, uncontrolled infections should avoid starting treatment until the infection is resolved.
• The safety and effectiveness in children have not been established.

Your healthcare provider will screen for hepatitis B and assess your overall health before starting treatment. If you have a history of severe allergic reactions to monoclonal antibodies, discuss this with your doctor.

Commonly used with

Ofatumumab is often used in combination with other chemotherapy agents for blood cancers:

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

These combinations are chosen based on the specific type and stage of the blood cancer, as well as patient factors such as age and other health conditions.

Commonly tested with

Ofatumumab has been tested in clinical trials with:

• Chlorambucil (for first-line treatment of CLL)
• Fludarabine and cyclophosphamide (for relapsed CLL)

It has also been studied as a single agent in patients with refractory CLL. These combinations have been shown to improve outcomes in certain groups of patients with blood cancers.