Chemical: Drug

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Annotated Labels

  1. FDA Label for ibritumomab and MS4A1
  2. EMA Label for ibritumomab and MS4A1

PharmGKB contains no Clinical Variants that meet the highest level of criteria.

Disclaimer: The PharmGKB's clinical annotations reflect expert consensus based on clinical evidence and peer-reviewed literature available at the time they are written and are intended only to assist clinicians in decision-making and to identify questions for further research. New evidence may have emerged since the time an annotation was submitted to the PharmGKB. The annotations are limited in scope and are not applicable to interventions or diseases that are not specifically identified.

The annotations do not account for individual variations among patients, and cannot be considered inclusive of all proper methods of care or exclusive of other treatments. It remains the responsibility of the health-care provider to determine the best course of treatment for a patient. Adherence to any guideline is voluntary, with the ultimate determination regarding its application to be made solely by the clinician and the patient. PharmGKB assumes no responsibility for any injury or damage to persons or property arising out of or related to any use of the PharmGKB clinical annotations, or for any errors or omissions.

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Generic Names
  • Ig gamma-2A chain C region, membrane-bound form
  • radiolabeled murine anti-CD20
Trade Names
  • Zevalin (IDEC Pharmaceuticals)
Brand Mixture Names

PharmGKB Accession Id





Indium conjugated murine IgG1 kappa monoclonal antibody directed against the CD20 antigen, which is found on the surface of normal and malignant B lymphocytes. Ibritumomab is produced in Chinese hamster ovary cells and is composed of two murine gamma 1 heavy chains of 445 amino acids each and two kappa light chains of 213 amino acids each.

Source: Drug Bank


For treatment of non-Hodgkin's lymphoma

Source: Drug Bank

Other Vocabularies

Information pulled from DrugBank has not been reviewed by PharmGKB.

Pharmacology, Interactions, and Contraindications

Mechanism of Action

The Fab segment of the antibody targets the CD20 epitope on B-cells, allowing the radioactive yttrium to destroy the cell via production of beta particles.

Source: Drug Bank


Ibritumomab is a murine monoclonal antibody against CD20 that has been radiolabeled with yttrium-90.

Source: Drug Bank

Absorption, Distribution, Metabolism, Elimination & Toxicity


Most likely removed by opsonization via the reticuloendothelial system when bound to B cells, or by human antimurine antibody production

Source: Drug Bank


0.8 hours (mammalian reticulocytes, in vitro)

Source: Drug Bank

Chemical Properties

Chemical Formula


Source: Drug Bank

Canonical SMILES

Not Available

Source: Drug Bank

Average Molecular Weight


Source: Drug Bank

Genes that are associated with this drug in PharmGKB's database based on (1) variant annotations, (2) literature review, (3) pathways or (4) information automatically retrieved from DrugBank, depending on the "evidence" and "source" listed below.

Curated Information ?

No Dosing Guideline available DL No Clinical Annotation available No Variant Annotation available No VIP available No VIP available

Drug Targets

Gene Description
C1QA (source: Drug Bank )
C1QB (source: Drug Bank )
C1QC (source: Drug Bank )
C1R (source: Drug Bank )
C1S (source: Drug Bank )
FCGR1A (source: Drug Bank )
FCGR2A (source: Drug Bank )
FCGR2B (source: Drug Bank )
FCGR2C (source: Drug Bank )
FCGR3A (source: Drug Bank )
FCGR3B (source: Drug Bank )
MS4A1 (source: Drug Bank )

Drug Interactions

Interaction Description
trastuzumab - ibritumomab Trastuzumab may increase the risk of neutropenia and anemia. Monitor closely for signs and symptoms of adverse events. (source: Drug Bank )
No related diseases are available


Web Resource:
Therapeutic Targets Database:

Clinical Trials

These are trials that mention ibritumomab and are related to either pharmacogenetics or pharmacogenomics.

No trials loaded.

NURSA Datasets

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No NURSA datasets available.

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Sources for PharmGKB drug information: DrugBank, PubChem.