# Gemtuzumab ozogamicin

Source: https://onco.cc/drugs/gemtuzumab-ozogamicin/  
OnCo record `gemtuzumab-ozogamicin` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Gemtuzumab ozogamicin (Mylotarg) is an anti-CD33 antibody linked to the DNA-cutting payload calicheamicin, the first ADC approved, in 2000 for relapsed acute myeloid leukaemia. An unstable linker and no benefit in a confirmatory trial led to withdrawal in 2010; it returned in 2017 at a lower fractionated dose, with liver toxicity, including veno-occlusive disease, its defining risk.

## Summary

Gemtuzumab ozogamicin (Mylotarg) is a humanised anti-CD33 IgG4 antibody linked through an acid-labile hydrazone to calicheamicin, a DNA cleaver that causes double-strand breaks, at a drug-to-antibody ratio of about 2 to 3. It was the very first ADC, approved in 2000 for relapsed CD33-positive AML, but this first-generation design had an unstable linker and heterogeneous conjugation, and it was withdrawn in 2010 after a confirmatory trial showed no benefit and excess deaths. Re-approval in 2017 was based on ALFA-0701, in which fractionated dosing (3 mg/m² on days 1, 4 and 7 with induction chemotherapy) improved event-free survival in CD33-positive AML. Hepatotoxicity including veno-occlusive disease, haemorrhage and infection are the key risks, so liver tests are checked before each dose. Its history shows that schedule and linker chemistry can decide the fate of a sound target.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-04
- Brand: Mylotarg
- Modality: ADC
- Mechanism: Anti-CD33 humanised IgG4 with calicheamicin; DNA double-strand cleavage.
- Payload: Calicheamicin (DNA cleaver), DAR ~2-3
- Linker: Acid-labile hydrazone
- Approvals: US 2000: Relapsed CD33+ AML (withdrawn 2010); US 2017: Newly diagnosed and relapsed CD33+ AML
- Dosing: IV infusion; Newly diagnosed AML: 3 mg/m² (max 4.5 mg) on days 1, 4, 7 of induction with daunorubicin/cytarabine; relapsed: 3 mg/m² days 1, 4, 7 as single agent

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Gemtuzumab_ozogamicin
- FDA label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?query=Gemtuzumab%20ozogamicin

## Connected records

- biomarkers: [CD33 expression (CD33-positive)](https://onco.cc/biomarkers/cd33-expression/)
- cancers: [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [Acute myeloid leukaemia in children](https://onco.cc/cancers/aml-paediatric/), [Acute promyelocytic leukaemia](https://onco.cc/cancers/apl/)
- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/)
- targets: [CD33](https://onco.cc/targets/cd33/)
- companies: [Pfizer (incl. Seagen)](https://onco.cc/companies/pfizer/)
- terms: [Acid-labile hydrazone (AcBut)](https://onco.cc/terms/hydrazone/), [Calicheamicin](https://onco.cc/terms/calicheamicin/), [DNA cleaver payloads (enediynes)](https://onco.cc/terms/dna-cleaver-payloads/)
- trials: [A Study to Compare Standard Chemotherapy to Therapy With CPX-351 and/or Gilteritinib for Patients With Newly Diagnosed AML With or Without FLT3 Mutations](https://onco.cc/trials/nct04293562/), [ALFA-0701](https://onco.cc/trials/alfa-0701/), [COG AAML0531](https://onco.cc/trials/aaml0531/)
- roadmaps: [ADC roadmap: from Mylotarg to bispecific and dual-payload ADCs](https://onco.cc/roadmaps/adc-generations/)
- key papers: [AAML0531: gemtuzumab ozogamicin added to chemotherapy for children and adolescents with acute myeloid leukaemia](https://onco.cc/key-papers/paper-aaml0531-gemtuzumab-gamis-jco-2014/)

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