Pronunciation: oh-bin-u-tuz-u-mab
Generic name: obinutuzumab
Brand name: Gazyva
Dosage form: single-dose vial for intravenous infusion (1000 mg/40 mL)
Drug class: CD20 monoclonal antibodies

Medically reviewed by Carmen Pope, BPharm. Last updated on Mar 16, 2025.

What is Obinutuzumab?

Obinutuzumab is used to treat chronic lymphocytic leukemia (CLL) or follicular lymphoma (FL) in patients who meet certain criteria. It is a targeted immunotherapy cancer treatment that works with your immune system and is given by a healthcare provider through an IV infusion alongside other cancer treatments.

Obinutuzumab (brand name Gazyva) gained FDA approval on November 1, 2013. There is no obinutuzumab generic or biosimilar.

FDA Approvals and Clinical Trials

Obinutuzumab is a prescription medicine that is FDA-approved in adults for:

• First-time treatment of CLL in combination with chlorambucil
• Follicular lymphoma in combination with bendamustine in patients who have relapsed or not responded to a rituximab-containing regimen. This is then followed by obinutuzumab alone as maintenance therapy
• First-time treatment of stage II bulky, III or IV follicular lymphoma. Used with chemotherapy first, then obinutuzumab alone if the treatment works.

The GALLIUM clinical trial compared obinutuzumab to rituximab for previously untreated follicular lymphoma (FL).

• After 7.9 years of follow-up, obinutuzumab showed a 7-year PFS (progression-free survival) rate of 63.4% versus 55.7% for rituximab.
• Time-to-next anti-lymphoma treatment was also better with obinutuzumab.
• While overall survival was similar, patients achieving complete molecular response had improved outcomes.

Other clinical trials have reported that in patients with CLL receiving obinutuzumab + chlorambucil:

• Almost 80% had a partial or complete response to treatment compared to 66.3% of those receiving a rituximab product + chlorambucil
• It took almost 1 year longer for their cancer to worsen (26.7 months compared to 14.9 months with a rituximab product + chlorambucil).

Mechanism

Obinutuzumab works by targeting a protein called CD20 that is found on normal and cancerous B-lymphocytes. Obinutuzumab binds to this protein which helps our immune system to identify and destroy the marked cells (see What is Gazyva (Obinutuzumab) used for and how does it work?).

Although obinutuzumab affects both healthy and cancerous B-cells, stem cells (young cells in the bone marrow that develop into various types of cells) are protected, which means your body maintains the ability to produce healthy blood cells throughout treatment.

Obinutuzumab belongs to the drug class called CD20 monoclonal antibodies. It may also be called a biologic, a targeted treatment, or immunotherapy.

Obinutuzumab side effects

The most common side effects of obinutuzumab are:

• infusion-related reactions
• low white blood cell counts.

Serious side effects and warnings

Obinutuzumab carries a Boxed Warning for hepatitis B reactivation and progressive multifocal leukoencephalopathy (PML) – a type of brain infection.

Hepatitis B Virus (HBV). If you have a history of hepatitis B infection, obinutuzumab could cause it to return which may result in liver failure or death. You should not receive obinutuzumab if you have active hepatitis B liver disease. Your doctor or healthcare team will need to screen you for hepatitis B before and monitor you during and after, your treatment. Sometimes this will require treatment for hepatitis B. Symptoms of hepatitis include: worsening of fatigue and yellow discoloration of skin or eyes.

Progressive Multifocal Leukoencephalopathy (PML). PML is a rare and serious brain infection caused by a virus. PML can be fatal. Your weakened immune system could put you at risk. Symptoms of PML include: confusion, difficulty talking or walking, dizziness or loss of balance, and vision problems.

Additional possible serious side effects of obinutuzumab include:

Infusion-Related Reactions (IRRs). These may occur during or within 24 hours of any obinutuzumab infusion and include severe allergic reactions (anaphylaxis), acute life-threatening breathing problems, or other life-threatening IRRs. If you react, the infusion is slowed or stopped until your symptoms are resolved. Most patients can complete infusions and receive medication again. However, if the IRR is life-threatening, the infusion of obinutuzumab will be permanently stopped. You may be given medicines before each obinutuzumab treatment to lessen this risk. Symptoms include fast heartbeat, tiredness, dizziness, headache, redness of the face, nausea, chills, fever, vomiting, diarrhea, rash, high blood pressure, low blood pressure, difficulty breathing, and chest discomfort.

Hypersensitivity Reactions Including Serum Sickness. Some people receiving obinutuzumab may have severe or life-threatening allergic reactions. This reaction may be severe, may happen during or after an infusion, and may affect many areas of the body. If an allergic reaction occurs, your doctor will stop the infusion and permanently discontinue obinutuzumab

Tumor Lysis Syndrome (TLS). Tumor lysis syndrome, including fatal cases, has been reported in patients receiving obinutuzumab. Obinutuzumab works to break down cancer cells quickly. As cancer cells break apart, their contents are released into the blood. These contents may cause damage to organs and the heart and may lead to kidney failure requiring the need for dialysis treatment. Your doctor may prescribe medication to help prevent TLS. Your doctor will also conduct regular blood tests to check for TLS. Symptoms of TLS may include nausea, vomiting, diarrhea, and tiredness

Infections. While you’re taking obinutuzumab, you may develop infections. Some of these infections may be fatal and severe, so be sure to talk to your doctor if you think you have an infection. Patients with a history of recurring or chronic infections may be at an increased risk of infection. Patients with an active infection should not be treated with obinutuzumab

Low White Blood Cell Counts. When you have an abnormally low count of infection-fighting white blood cells, it is called neutropenia. While you are taking obinutuzumab, your doctor will do blood work to check your white blood cell count. Severe and life-threatening neutropenia can develop during or after treatment with obinutuzumab. Some cases of neutropenia can last for more than one month. If your white blood cell count is low, your doctor may prescribe medication to help prevent infections.

Low Platelet Counts. Platelets help stop bleeding or blood loss. Obinutuzumab may reduce the number of platelets you have in your blood; having low platelet count is called thrombocytopenia. This may affect the clotting process. While you are taking obinutuzumab, your doctor will do blood work to check your platelet count. Severe and life-threatening thrombocytopenia can develop during treatment. Fatal bleeding events have occurred in patients treated with this medicine. If your platelet count gets too low, your treatment may be delayed or reduced.

Disseminated Intravascular Coagulation (DIC). Fatal and severe DIC has been reported in people receiving obinutuzumab. DIC is a rare and serious abnormal blood clotting condition that should be monitored and managed by your doctor as it can lead to uncontrollable bleeding.

These are not all the possible side effects of obinutuzumab. For more information, ask your doctor or pharmacist.

Tell your doctor right away about any side affects you experience. You may report side effects to the FDA at (800) FDA-1088, or www.fda.gov/medwatch. You may also report side effects to Genentech at (888) 835-2555.

Related/similar drugs

Before receiving

Do NOT receive obinutuzumab if you have had an allergic reaction (such as anaphylaxis or serum sickness) to obinutuzumab, Gazyva, or any other ingredients in the injection.

Before receiving obinutuzumab tell your doctor about all your medical conditions and treatments including if you:

• Have heart disease
• Have an infection, especially a viral infection, such as hepatitis B
• Have a lung or breathing disease
• Have recently received or are scheduled to receive a vaccine
• Take medications that treat or prevent blood clots
• Are pregnant or trying to get pregnant
• Are breastfeeding.

Pregnancy

Obinutuzumab may harm your unborn baby. Speak to your doctor about using this medicine while you are pregnant. Talk to your doctor or your child’s doctor about the safety and timing of live virus vaccinations for your infant if you received obinutuzumab during pregnancy. Women of childbearing potential should use effective contraception while taking obinutuzumab and for 6 months after you finish treatment.

Breastfeeding

Because of the potential risk of serious side reactions in breastfed children, women should not breastfeed while taking obinutuzumab and for 6 months after their last dose.

How is obinutuzumab administered?

Obinutuzumab is given as an infusion by a healthcare provider in a clinic or infusion center.

• It is given for 6 cycles (also called rounds) of treatment.
• Each cycle will last 28 days
• Each dose is the same except for the first 2 days of cycle 1. This is done to help reduce side effects you may have during the infusion.

Most people will complete their obinutuzumab treatment in about 6 months.

Patient information is available for obinutuzumab for:

• Previously Untreated Follicular Lymphoma (FL)
• Relapsed/Refractory Follicular Lymphoma (FL)
• Untreated Chronic Lymphocytic Leukemia (CLL)

Preparing for a obinutuzumab infusion

On the days you receive obinutuzumab, you should expect to spend most of the day at the clinic or infusion center.

1 week before your obinutuzumab infusion

• Tell your doctor about all the medicines you take, including prescription and non-prescription medicine, vitamins, and herbal supplements.
• Speak to your doctor if you take medications to control your blood pressure. Your doctor may instruct you not to take them on the day of your infusion.
• Arrange a ride. After your infusion, you may feel drowsy or dizzy. It is a good idea to have someone else drive you home.

1 day before your obinutuzumab infusion

• Remember to follow any changes your doctor has made to your regular medication schedule.

Infusion day

• Wear or bring loose clothing so you can be comfortable during your infusion.
• Pack food and drink—bringing some snacks or a packed meal can help you get through the day.
• Bring a book or activities to help pass the time.

1 hour before the infusion

Your doctor may give you medications to take one hour before your infusion. These are called premedications and may include:

• Acetaminophen
• Antihistamines
• Steroid medications.

Taking these medications before treatment may reduce the chance of possible side effects during your obinutuzumab infusion.

During the infusion

Relax during your infusion, but be aware of what is happening to your body. Tell your doctor or nurse right away if you feel any side effects, including the symptoms of an infusion reaction.

Once you begin treatment, your doctor will need to regularly check:

• Symptoms
• Size of your lymph nodes, liver, or spleen
• Blood count measures.

Obinutuzumab dosing schedule

The dose of obinutuzumab is gradually increased during Cycle 1 to reduce the risk of infusion-related reactions and other side effects.

• For Cycles 2 through 6, you will receive obinutuzumab on the first day of each cycle (1 time every 28 days).
• If you have CLL, you will receive chlorambucil on Day 1 and Day 15 of Cycles 1 through 6.

Cycle 1

• Day 1 infusion: 100 mg
• Day 2 infusion: 900 mg
• Day 8 infusion: 1000 mg
• Day 15 infusion: 1000 mg
• Day 16 to 28: No infusion

Cycle 2

• Day 1 infusion: 1000 mg
• Day 2 to 28: No infusion

Cycles 3 through 6

• Day 1 infusion: 1000 mg
• Day 2 to 28: No infusion

What should I avoid while receiving obinutuzumab?

Do not receive live vaccines (such as the BCG, MMR, MMRV, rotavirus, or varicella vaccines) while you are being treated with obinutuzumab.

Manufacturer

Obinutuzumab is manufactured under the brand name Gazyva by Genentech, which is a subsidiary of Roche. Genentech is based in South San Francisco, California, while Roche's global headquarters is in Basel, Switzerland. Notable drugs from Genentech/Roche include:

Cancer Treatments:

• Avastin (bevacizumab)
• Herceptin (trastuzumab)
• Rituxan (rituximab)
• Tecentriq (atezolizumab)
• Perjeta (pertuzumab)

Other Key Medicines:

• Actemra (tocilizumab) for rheumatoid arthritis
• Ocrevus (ocrelizumab) for multiple sclerosis
• Lucentis (ranibizumab) for eye conditions
• Xolair (omalizumab) for asthma and allergies
• Hemlibra (emicizumab) for hemophilia A.

Obinutuzumab Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for obinutuzumab.

Popular FAQ

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer