How it is administered

Obinutuzumab is given as an intravenous (IV) infusion, meaning it is administered directly into a vein by a healthcare professional. It is not given as a rapid injection (IV push or bolus), but rather slowly over several hours. The medication comes as a liquid concentrate that is diluted and infused via a dedicated IV line.

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

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

For follicular lymphoma (FL), the dosing is:

• Cycle 1: 1,000 mg on Days 1, 8, and 15
• Cycles 2–6 (or 2–8): 1,000 mg on Day 1 of each cycle
• Then, 1,000 mg every 2 months for up to 2 years as maintenance therapy

Premedication with steroids, acetaminophen, and antihistamines is recommended to reduce the risk of infusion-related reactions.

How it works

Obinutuzumab is a monoclonal antibody that specifically targets the CD20 protein found on the surface of certain B cells, which are a type of white blood cell involved in some blood cancers like CLL and FL.

When obinutuzumab binds to CD20, it helps the immune system recognize and destroy these B cells. It does this in several ways:

• It recruits immune cells to attack and kill the targeted B cells (antibody-dependent cellular cytotoxicity and phagocytosis).
• It can directly trigger the death of the B cells by activating internal cell death pathways.
• It can also activate the complement system, which is another part of the immune system that helps destroy cells.

Obinutuzumab is engineered to have reduced fucose content, which increases its ability to recruit immune cells and kill cancerous B cells compared to some other anti-CD20 antibodies. By depleting these abnormal B cells, obinutuzumab helps to control the progression of blood cancers.

Who Should take it

Obinutuzumab is used for adults with certain types of blood cancers:

• In combination with chlorambucil, it is indicated for patients with previously untreated chronic lymphocytic leukemia (CLL).
• In combination with bendamustine followed by obinutuzumab alone, it is used for follicular lymphoma (FL) patients who have relapsed after, or are refractory to, a rituximab-containing regimen.
• In combination with chemotherapy (such as CHOP or CVP) followed by obinutuzumab alone, it is used for adults with previously untreated stage II bulky, III, or IV follicular lymphoma.

Your doctor will determine if obinutuzumab is appropriate for you based on your diagnosis, previous treatments, and overall health.

Who should not take it

Obinutuzumab should not be used in patients who have had a known hypersensitivity reaction (such as anaphylaxis) to obinutuzumab or any of its ingredients, or who have experienced serum sickness with prior obinutuzumab use.

It should not be given to patients with active infections. Caution is also advised in patients with a history of recurring or chronic infections, as they may be at higher risk of serious infections during treatment. Pregnant women should avoid this medication due to potential harm to the fetus, and women should use effective contraception during and for 6 months after treatment. Live vaccines should not be administered during treatment and until B-cell recovery.

Commonly used with

Obinutuzumab is commonly used in combination with other chemotherapy agents, depending on the type of blood cancer being treated. For CLL, it is used with chlorambucil. For follicular lymphoma, it is used with bendamustine, CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone), or CVP (cyclophosphamide, vincristine, prednisone), followed by obinutuzumab alone as maintenance therapy.

Your doctor will decide the best combination based on your specific condition.

Commonly tested with

Obinutuzumab has been tested in clinical trials in combination with various chemotherapy regimens, including chlorambucil for CLL and bendamustine, CHOP, or CVP for follicular lymphoma. It is often compared to or used after rituximab-containing regimens in studies to determine its effectiveness and safety in patients who have relapsed or are refractory to rituximab.