How it is administered

Obinutuzumab is administered as an intravenous (IV) infusion. It is not given as a push or bolus injection. The medication comes as a liquid concentrate that is diluted and infused through a vein by a healthcare professional in a clinic or hospital setting.

For chronic lymphocytic leukemia (CLL), the typical dosing schedule is:

• Cycle 1: 100 mg on day 1, 900 mg on day 2, and 1,000 mg on days 8 and 15.
• Cycles 2–6: 1,000 mg on day 1 of each 28-day cycle.

Premedication with glucocorticoids, acetaminophen, and antihistamines is required before each infusion to reduce the risk of infusion-related reactions.

How it works

Obinutuzumab is a monoclonal antibody that targets a protein called CD20 found on the surface of certain B cells, including those involved in chronic lymphocytic leukemia (CLL). By binding to CD20, obinutuzumab helps the immune system recognize and destroy these cancerous B cells.

It works through several mechanisms: it directly activates cell death pathways inside the B cells, triggers immune cells to attack and kill the B cells (a process called antibody-dependent cellular cytotoxicity and phagocytosis), and can also activate the complement system, which further helps eliminate the targeted cells. Obinutuzumab was engineered to have enhanced activity compared to similar medications, leading to more effective depletion of B cells. This reduction in abnormal B cells helps control the progression of CLL.

Who Should take it

Obinutuzumab is approved for adults with previously untreated chronic lymphocytic leukemia (CLL), in combination with another medication called chlorambucil. It is also used for certain types of follicular lymphoma, but its main use in CLL is for patients who have not received prior treatment.

It is especially considered for patients who may not be able to tolerate more intensive chemotherapy due to age or other health conditions. Your doctor will decide if obinutuzumab is right for you based on your specific diagnosis, overall health, and other medications you may be taking.

Who should not take it

You should not take obinutuzumab if you have had a severe allergic reaction (such as anaphylaxis) or serum sickness to obinutuzumab or any of its ingredients. It is also contraindicated in patients with known hypersensitivity to any of the excipients in the formulation.

Obinutuzumab should not be given to patients with active infections. If you have a history of hepatitis B infection, your doctor will need to monitor you closely, as the medication can cause reactivation of the virus. It is not recommended to receive live vaccines during treatment and until your immune system has recovered.

Commonly used with

In chronic lymphocytic leukemia, obinutuzumab is most commonly used in combination with chlorambucil. This combination has been shown to improve outcomes compared to either medication alone.

For other blood cancers, such as follicular lymphoma, it may be used with bendamustine or other chemotherapy regimens. Your doctor will choose the best combination based on your specific disease and health status.

Commonly tested with

Obinutuzumab has been tested in combination with chlorambucil for CLL, and with bendamustine, CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone), or CVP (cyclophosphamide, vincristine, prednisone) for follicular lymphoma.

Clinical studies have compared obinutuzumab combinations to other standard treatments, such as rituximab-based regimens, to determine effectiveness and safety.