How it is administered

Obinutuzumab is given as an intravenous (IV) infusion. It is not administered as an IV push or bolus. 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 follicular lymphoma (a type of blood cancer related to large B cell lymphoma), the typical dosing schedule is:

• 1,000 mg on days 1, 8, and 15 of the first cycle
• 1,000 mg on day 1 of cycles 2–6 (or up to cycle 8, depending on the chemotherapy regimen)
• After initial treatment, 1,000 mg every two months for up to two 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 targets a protein called CD20 found on the surface of B cells, which are a type of white blood cell involved in many blood cancers, including large B cell lymphoma. By binding to CD20, obinutuzumab helps the immune system recognize and destroy these cancerous B cells.

It works in several ways:

• It recruits immune effector cells to attack and kill the B cells (antibody-dependent cellular cytotoxicity and phagocytosis).
• It directly activates cell death pathways inside the B cells.
• It can also trigger the complement system, another part of the immune response, to destroy the B cells.

Obinutuzumab is engineered to have greater activity than some other anti-CD20 antibodies, leading to more effective killing of cancerous B cells.

Who Should take it

Obinutuzumab is approved for use in adults with certain types of blood cancers, including follicular lymphoma and chronic lymphocytic leukemia (CLL). For follicular lymphoma, it is used:

• In combination with chemotherapy for patients who have not been treated before (previously untreated)
• In combination with bendamustine for patients whose disease has returned or did not respond to previous treatment with rituximab
• As maintenance therapy after a response to initial treatment

Patients with large B cell lymphoma may sometimes receive obinutuzumab off-label or as part of clinical trials, especially if other treatments have not worked. Your doctor will determine if obinutuzumab is right for you based on your specific diagnosis and treatment history.

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 in the past.

Obinutuzumab should not be given to patients with active infections. It is also not recommended for use in people who have not recovered from previous severe reactions to this medication. If you have a history of hepatitis B infection, your doctor will monitor you closely, as this medication can cause the virus to reactivate. Obinutuzumab is not recommended during pregnancy, as it may harm the unborn baby. Women of childbearing potential should use effective contraception during treatment and for 6 months after the last dose.

Commonly used with

Obinutuzumab is commonly used in combination with chemotherapy drugs such as:

• Bendamustine
• CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone)
• CVP (cyclophosphamide, vincristine, prednisone)

After initial combination therapy, it may be continued alone as maintenance therapy to help prevent the cancer from returning.

Commonly tested with

Obinutuzumab has been tested in clinical trials with various chemotherapy regimens, including bendamustine, CHOP, and CVP, for the treatment of follicular lymphoma and other B cell lymphomas. It is often compared to rituximab, another anti-CD20 antibody, in these studies.

It is also studied in combination with other targeted therapies and immunotherapies in ongoing research for blood cancers.