Logo

OpiCalc

FavoritesSpecialtiesDrugsGuidelinesMost Used

Quick Access

Favorites
Most Used

All Specialties

OpiCalc Logo
Clinical CalculatorsDrugsGuidelines
SpecsDrugsGuides
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
OpiCalc Logo

OpiCalc

Easy, fast, and private medical tools for clinicians. Always free.

No Login Required
Ready for the Bedside

Resources

About UsEditorial PolicyMedical DisclaimerPrivacy PolicyTerms of UseCookie Policy

Support

Contact Us

Clinical Notice:OpiCalc is not a substitute for professional clinical judgment. Always verify dosages and guidelines.

OpiCalc © 2026

•

All Rights Reserved

Registry Hub
CD20-directed Monoclonal Antibody/Prescription

GAZYVA

GAZYVA

Clinical safety rating

caution

Comprehensive clinical and safety monograph for GAZYVA (GAZYVA).


What is GAZYVA?

Comprehensive clinical and safety monograph for GAZYVA (GAZYVA).

Indications & Uses

Chronic lymphocytic leukemia (CLL) in combination with chlorambucilFollicular lymphoma (FL) in combination with bendamustine followed by obinutuzumab monotherapy for patients with relapsed or refractory FLPreviously untreated follicular lymphoma in combination with chemotherapy

Compare GAZYVA vs OCREVUS →View all CD20-directed Monoclonal Antibody drugs →

Mechanism of Action

Obinutuzumab is a type II anti-CD20 monoclonal antibody that binds to the CD20 antigen on B cells, inducing direct cell death, antibody-dependent cellular cytotoxicity, and antibody-dependent cellular phagocytosis.

What the body does with it

MetabolismObinutuzumab is a monoclonal antibody expected to be degraded into small peptides and amino acids via catabolic pathways, similar to endogenous immunoglobulins; not metabolized by CYP450 enzymes.
ExcretionObinutuzumab is eliminated primarily through intracellular catabolism, with no significant renal or biliary excretion. <1% of the dose is excreted unchanged in urine.
Half-lifeThe terminal elimination half-life is approximately 28 days (range 14-42 days) following the last dose, supporting a 6-month dosing interval for maintenance therapy.
Protein bindingObinutuzumab binds specifically to CD20 antigen on B-cells; plasma protein binding is negligible (<1%) as it is a monoclonal antibody.
Volume of DistributionThe volume of distribution is approximately 3.8 L (0.05 L/kg for a 70 kg adult), reflecting limited extravascular distribution primarily to lymphoid tissues.
BioavailabilityObinutuzumab is only administered intravenously; oral bioavailability is 0%. Subcutaneous formulations are not available.
Onset of ActionIntravenous administration: Maximum plasma concentration is reached at the end of infusion. Pharmacodynamic effects (B-cell depletion) are observed within 24 hours.
Duration of ActionB-cell depletion persists for at least 6 months after the last dose. Recovery of B-cell counts begins after 9-12 months, with normalization typically within 12-18 months.
Molecular Weight146000

Classification & Brands

Dosing & administration

100 mg intravenously on day 1, 8, 15 of cycle 1, then 100 mg on day 1 of subsequent 28-day cycles for 6 cycles total.

Dosage formINJECTABLE
Renal impairmentNo dose adjustment required for mild to moderate renal impairment (CrCl >=30 mL/min). Safety and efficacy not established in severe renal impairment (CrCl <30 mL/min).
Liver impairmentNo dose adjustment required for mild hepatic impairment (Child-Pugh A). Not recommended for moderate to severe hepatic impairment (Child-Pugh B or C).
Pediatric useSafety and efficacy not established in pediatric patients.
Geriatric useNo specific dose adjustment required; monitor for infusion-related reactions and hematologic toxicities more frequently.

Use during pregnancy

1st trimesterAvoid use during first trimester due to risk of fetal B-cell depletion based on known effects of anti-CD20 antibodies.
2nd trimesterAvoid use during second trimester due to potential fetal B-cell depletion and variable placental transfer.
3rd trimesterAvoid use during third trimester due to risk of neonatal B-cell depletion and immunosuppression.

Clinical note

Comprehensive clinical and safety monograph for GAZYVA (GAZYVA).

Placental transferIgG monoclonal antibodies, such as obinutuzumab, are known to cross the placenta; transfer increases as gestation progresses, with the highest levels in the third trimester.
BreastfeedingIt is not known whether obinutuzumab is excreted in human milk. Given the potential for adverse reactions in the breastfed infant, including B-cell depletion, women should discontinue breastfeeding during treatment and for at least 18 months after the last dose.
Lactation RatingL5
Teratogenic RiskFirst trimester: limited human data, but based on mechanism (anti-CD20 monoclonal antibody), potential B-cell depletion in fetus. Second/third trimesters: IgG crosses placenta; fetal B-cell depletion and cytopenias possible. Avoid unless benefit outweighs risk.
Fetal MonitoringMonitor maternal CBC with differential, LFTs, and hepatitis B serology before and during treatment. For pregnant women, fetal ultrasound for growth and amniotic fluid assessment; consider monitoring for neonatal cytopenias and infections after birth.
Fertility EffectsNo human data. In animal studies, no significant adverse effects on male or female fertility observed; however, B-cell depletion in reproductive tissues may occur.

Warnings & precautions

■ FDA Black Box Warning

Hepatitis B virus reactivation, including fulminant hepatitis, hepatic failure, and death; Progressive multifocal leukoencephalopathy (PML) resulting in death.

Side Effect Profile

Serious Effects

Absolute Contraindications

Known hypersensitivity to obinutuzumab or any of its excipientsActive hepatitis B infection

Clinical Precautions

PrecautionsInfusion reactions (including severe and life-threatening reactions), Tumor lysis syndrome, Neutropenia and thrombocytopenia, Infections (including severe and opportunistic infections), Hepatitis B reactivation, Progressive multifocal leukoencephalopathy (PML), Immunization with live viral vaccines
Food/DietaryNo known food interactions. Grapefruit and other CYP3A4 inhibitors are not expected to affect obinutuzumab as it is a monoclonal antibody cleared by non-renal, non-hepatic mechanisms.

Clinical Tips & Counseling

Clinical PearlsAdminister premedication (acetaminophen, antihistamine, corticosteroid) for infusion reactions. Monitor for tumor lysis syndrome (TLS) and provide prophylaxis (hydration, uric acid reducers) in high-risk patients. Do not administer live vaccines during treatment. Screen for hepatitis B virus (HBV) infection before initiation. Use in CLL patients with del(17p) or TP53 mutation is an NCCN category 1 recommendation.
Patient AdviceYou will receive premedication before each infusion to reduce infusion reactions. · Report any fever, chills, rash, or difficulty breathing during or after infusion immediately. · Do not receive live vaccines during treatment and for at least 6 months after last dose. · Your doctor will monitor for signs of tumor lysis syndrome (e.g., nausea, vomiting, muscle cramps, seizures). · You may be at increased risk of infections; report any signs of infection (fever, cough, sore throat). · This drug can lower blood counts; you may need regular blood tests.

GAZYVA Interactions

Loading safety data…

This overview is compiled from peer-reviewed clinical sources and FDA labeling. It's here to support — not replace — clinical judgment. Always verify dosing against your institution's current protocols before prescribing.

On this page

Mechanism of ActionDosing & administrationUse during pregnancyWarnings & precautionsDrug interactions

Compare with

OCREVUSOCREVUS ZUNOVO

External sources

DailyMed (NIH) PubMed OpenFDA