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Generic name: obinutuzumab
Brand name: Gazyva
Dosage form: intravenous (infusion) injection
Drug class: CD20 monoclonal antibodies

Medically reviewed by Philip Thornton, DipPharm. Last updated on Apr 4, 2023.

What is obinutuzumab?

Obinutuzumab is a type of targeted chemotherapy drug for the treatment of certain blood cancers.

Obinutuzumab is a biological drug called a monoclonal antibody that targets and attaches to CD20, a protein found on the surface of a type of white blood cells called B-cells.

B-cells, or B-lymphocytes as they are also known, usually help your body fight off infection, but some people produce abnormal numbers of B-cells which leads to cancer.

Obinutuzumab works by binding to normal and cancerous B-cells, marking them for destruction. Obinutuzumab works by calling in your own immune system cells to attack and break apart the marked B-cells, and by activating processes within the B-cells that instruct them to die.

Obintuzumab was approved by the US Food and Drug Administration (FDA) in 2013. No biosimilars of obintuzumab have been approved. Biosimilars are highly similar versions of the drug that are designed to have the same effect on a person, but a biosimilar is not identical to the original version of the drug.

What is obinutuzumab used for?

Obinutuzumab is a prescription medication used in combination with:

  • chlorambucil, for the treatment of patients with previously untreated chronic lymphocytic leukemia.
  • bendamustine followed by obinutuzumab alone, for the treatment of patients with follicular lymphoma who relapsed after, or are refractory to, a rituximab-containing regimen.
  • chemotherapy followed by obintuzumab alone in patients achieving at least a partial remission, for the treatment of adult patients with previously untreated stage II bulky, III or IV follicular lymphoma.

Important information

Obintuzumab can cause serious side effects including:

  • Hepatitis B Virus (HBV): Hepatitis B can cause liver failure and death. If you have a history of hepatitis B infection, obintuzumab could cause it to return. You should not receive obintuzumab 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 with obintuzumab. 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. Your doctor will watch for symptoms. Symptoms of PML include: confusion, difficulty talking or walking, dizziness or loss of balance, and vision problems

Who should not receive obinutuzumab?

Do not receive obinutuzumab if you have had an allergic reaction (e.g., anaphylaxis or serum sickness) to obinutuzumab. Tell your healthcare provider if you have had an allergic reaction to obinutuzumab or any other ingredients in it in the past. See below for a complete list of ingredients in obintuzumab.

What should I tell my doctor before receiving obinutuzumab?

Before receiving obinutuzumab, tell your healthcare provider about all of your medication conditions, including if you:

  • have recently received or are scheduled to receive a vaccine. People who are treated with obinutuzumab should not receive live vaccines
  • have a history of hepatitis B virus infection
  • have high blood pressure
  • have a bleeding disorder

How should I receive obinutuzumab?

  • When preparing to receive obinutuzumab follow all of the instructions your healthcare professional has given you, which may include adjusting when you take other medications.
  • Before your obinutuzumab infusion is given you may receive other medications to help reduce the chances of certain side effects or an allergic reaction.
  • Obinutuzumab is administered by a healthcare professional at a treatment center.
  • Obinutuzumab is given by intravenous infusion, which means it goes directly into your vein through a needle in your arm. It will be administered over a period of 3-5 hours to begin with, but in some cases the infusion time may be able to be shortened to 90 minutes.
  • Depending on the type of cancer you have, obinutuzumab will be administered alone or in combination with other treatments on a 21 or 28 day cycle for 6 months.
  • Depending on the type of cancer you have and your response to treatment, you may be offered treatment with obinutuzumab for up to 2 years after your initial 6-month course. Obinutuzumab is given every 2 months in this situation.
  • Your healthcare professional will tell you which treatment schedule is right for you.
  • Your healthcare professional may order blood tests to check for side effects.

What happens if I miss a dose?

If you miss a dose of obinutuzumab it should be administered as soon as possible. Your healthcare professional will discuss with you what adjustments need to be made to your treatment schedule if you miss a dose.

What should I avoid while receiving obinutuzumab?

While receiving treatment with obinutuzumab you should avoid vaccination with live viral vaccines.

Dosing information

  • Before administration of obinutuzumab, you will receive medication to help prevent infusion-related reactions and tumor lysis syndrome.
  • Obinutuzumab is administered by intravenous infusion. It is not administer as an intravenous push or bolus.
  • The recommended dosage for chronic lymphocytic leukemia is obinutuzumab 100 mg on day 1 and 900 mg on day 2 of Cycle 1, 1,000 mg on day 8 and 15 of Cycle 1, and 1,000 mg on day 1 of Cycles 2–6.
  • The recommended dosage for follicular lymphoma is obinutuzumab 1,000 mg on day 1, 8 and 15 of Cycle 1, 1,000 mg on day 1 of Cycles 2-6 or Cycles 2-8, and then 1,000 mg every 2 months for up to 2 years.
  • See the full prescribing information for further details about obinutuzumab dosing.

What are the side effects of obinutuzumab?

Obinutuzumab can cause serious side effects including:

  • See "Important information" above
  • Hepatitis B virus reactivation
  • Progressive multifocal leukoencephalopathy
  • Infusion-Related Reactions (IRRs): These side effects may occur during or within 24 hours of any obinutuzumab infusion. Some IRRs can be serious, including, but not limited to, severe allergic reactions (anaphylaxis), acute life-threatening breathing problems, or other life-threatening IRRs. If you have a reaction, the infusion is either slowed or stopped until your symptoms are resolved. Most patients are able to complete infusions and receive medication again. However, if the IRR is life-threatening, the infusion of obinutuzumab will be permanently stopped. Your healthcare team will take steps to help lessen any side effects you may have to the infusion process. You may be given medicines to take before each obinutuzumab treatment. Symptoms of IRRs may include:
    • fast heartbeat
    • tiredness
    • dizziness
    • headache
    • redness of the face
    • nausea, chills
    • fever
    • vomiting
    • diarrhea
    • rash
    • high blood pressure
    • low blood pressure,
    • difficulty breathing
    • 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. Obintuzumab 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
    • 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 administered obinutuzumab in combination with chemotherapy, followed by obintuzumab alone are at a high risk of infections during and after treatment. 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. Patients taking obinutuzumab plus bendamustine may be at higher risk for fatal or severe infections compared to patients taking obintuzumab plus CHOP or CVP.
  • Low White Blood Cell Count: 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 Count: Platelets help stop bleeding or blood loss. Obinutuzuamb 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 with obinutuzumab. Fatal bleeding events have occurred in patients treated with obinutuzumab. If your platelet count gets too low, your treatment may be delayed or reduced

The most common side effects seen with obinutuzumab in a study that included previously untreated follicular lymphoma patients were:

  • infusion-related reactions
  • low white blood cell count
  • upper respiratory tract infections
  • cough
  • constipation
  • diarrhea

These are not all of the possible side effects of obinutuzumab. Tell your healthcare provider about all of your side effects. Call your doctor or pharmacist for medical advice about side effects. You may report side effects to Genentech at 1-888-835-2555 or FDA at 1-800-FDA-1088 or


Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Especially tell your doctor if you take medication:

  • for high blood pressure (hypertension). Your doctor may tell you not to take your medication for high blood pressure on the day of you obinutuzumab infusion.
  • that may increase your risk of bleeding, such as blood thinners or medications to prevent clots. Check with your pharmacist if you are not sure. Your doctor may tell you not to take these medications, especially during your first treatment cycle.

Pregnancy and breastfeeding

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

Tell your doctor if you are breastfeeding or plan to breastfeed. Because of the potential risk of serious side reactions in breastfed children, women should not breastfeed while taking obinutuzumab and for 6 months after your last dose.


  • Store obinutuzumab at 2°C to 8°C (36°F to 46°F).
  • Do not use beyond expiration date stamped on carton.
  • Protect from light.
  • Do not freeze.
  • Do not shake.

Keep out of reach of children.

What are the ingredients in obinutuzumab?

Active ingredient:obinutuzumab

Inactive ingredients:histidine, histidine monohydrochloride monohydrate, trehalose dihydrate, poloxamer 188, water

Obinutuzumab is manufactured by Genentech, Inc. A Member of the Roche Group, South San Francisco, CA 94080-4990.

Frequently asked questions

Further information

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