Drugs › CD33-directed immunoconjugate
Generic name
Gemtuzumab ozogamicin: adverse event reports filed with FDA
1,560 reports list it as a suspect or interacting product, 2004–2026. Class: CD33-directed immunoconjugate. Also reported as Gemtuzumab Ozogamicin Injection.
- 1,560
- reports as suspect product
- 0% of all reports · about 69 a year
- 43
- reports, 12 months to June 2026
- 59 in the 12 months before
- 99.7%
- marked serious by the reporter
- 97.3% across the class
- 32.4%
- record death among outcomes, as reported
- 505 reports · not verified by FDA
Between January 2004 and June 2026, 1,560 adverse event reports received by FDA list gemtuzumab ozogamicin, a generic name as a suspect or interacting product. Reports that mention it only as a concomitant medication (271) are left out of every figure here.
In the 12 months to June 2026, 43 reports listed it, down 27% from 59 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 69 reports a year and 0% of the 20,646,523 reports in the database, and 46.2% of the reports for the CD33-directed immunoconjugate class. How many people take it is not in the data, so a count is not a rate of occurrence.
The MedDRA terms listed most often are febrile neutropenia (20.7%), sepsis (8.3%) and venoocclusive liver disease (7.9%). A report can list several reactions, so shares add to more than 100%; 333 different terms appear across these reports. Febrile neutropenia is recorded in 20.7% of these reports, about the same share as in the median CD33-directed immunoconjugate drug (19.5%).
99.7% of the reports are marked serious by the reporter (97.3% across the class); 32.4% record death among the outcomes and 46.1% record hospitalisation, as reported. 54% of the reports came from physicians, and the largest patient age group is 45 to 64 (23.3%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."
Reports by month, five years
Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.
By year received
2026 covers reports received through June 2026 only.
Reactions recorded in the reports
share of Gemtuzumab ozogamicin reports recording the termmedian drug in cd33-directed immunoconjugate
- Febrile neutropeniafever with low white blood cells20.7%323
- Sepsisa severe body-wide response to infection8.3%129
- Venoocclusive liver disease7.9%123
- Thrombocytopenialow platelets6.2%96
- Pyrexiafever6.1%95
- Neutropenialow neutrophils, a type of white blood cell5.4%85
- Drug ineffectivethe medicine did not work as expected5.3%83
- Pneumonialung infection4.6%72
- Off label useused for a purpose or in a way not on the label3.8%59
- Hypotensionlow blood pressure3.3%51
- Septic shockshock arising from infection3.1%49
- Platelet count decreasedlow platelet count2.7%42
- Alanine aminotransferase increasedraised liver enzyme (ALT)2.6%40
- Disease progressionthe disease advanced2.5%39
- Acute myeloid leukaemia2.4%37
- Multi-organ failure2.2%34
- Renal failurekidney failure2.2%34
- Cerebral haemorrhage2.1%33
- Deaththe patient died; cause not stated by this term2.1%33
- Respiratory failurethe lungs could not supply enough oxygen2.1%32
- Drug resistance1.9%30
- Diarrhoealoose or frequent stools1.8%28
- Chillschills or shivering1.7%27
- Mucosal inflammation1.7%26
- Pancytopenialow counts of all blood cells1.6%25
- Aspartate aminotransferase increasedraised liver enzyme (AST)1.5%24
- Infectionan infection, type not specified1.5%24
- White blood cell count decreasedlow white cell count1.5%24
- Anaemialow red blood cells1.5%23
Top 30 of 333 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 2 drugs in the cd33-directed immunoconjugate class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."
Outcomes recorded
Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 3,378 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."
Patients and reporters
Patient age
Patient sex
Who reported
Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 20.6% of reports give the United States as the country of the event or reporter.
Reason for use recorded
| Indication as recorded (MedDRA) | Reports | Share |
|---|---|---|
| Acute myeloid leukaemia | 1,018 | 65.3% |
| Acute myeloid leukaemia refractory | 33 | 2.1% |
| Myelodysplastic syndrome | 32 | 2.1% |
| Acute promyelocytic leukaemia | 29 | 1.9% |
| Acute myeloid leukaemia recurrent | 25 | 1.6% |
| Acute leukaemia | 23 | 1.5% |
The indication field is filled in by the reporter and is often blank; shares are of all 1,560 reports.
Drugs most often listed in the same reports
| Drug (any role in the report) | Reports | Share of Gemtuzumab ozogamicin reports |
|---|---|---|
| Cytarabine | 858 | 55% |
| Etoposide | 237 | 15.2% |
| Daunorubicin | 205 | 13.1% |
| Daunorubicin hydrochloride | 153 | 9.8% |
| Mitoxantrone | 151 | 9.7% |
| Ondansetron | 139 | 8.9% |
| Fludarabine | 132 | 8.5% |
| Mitoxantrone hydrochloride | 119 | 7.6% |
| Vancomycin | 104 | 6.7% |
| Cyclophosphamide | 95 | 6.1% |
Other products listed in reports where Gemtuzumab ozogamicin is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.
In context
| Measure | Gemtuzumab ozogamicin | CD33-directed immunoconjugate | All reports |
|---|---|---|---|
| Reports as suspect product | 1,560 | 3,378 | 20,646,523 |
| Share of that pool | — | 46.2% | 0% |
| Reports, latest 12 months | 43 | — | 1,332,454 |
| Marked serious | 99.7% | 97.3% | 57.4% |
| Death recorded among outcomes, per 1,000 reports | 324 | 319 | 91 |
| Hospitalisation recorded, per 1,000 reports | 461 | 483 | 213 |
| Consumer-filed share | 2.6% | 3.8% | 45.8% |
| Top term, share of reports | Febrile neutropenia 20.7% | median 19.5% | 0.3% |
Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."
Other drugs in the cd33-directed immunoconjugate class
| Drug | Name type | Reports | Latest 12 months | Marked serious |
|---|---|---|---|---|
| Mylotarg | brand | 1,818 | 33 | 95.2% |
Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.
Questions about Gemtuzumab ozogamicin reports
How many adverse event reports has FDA received for Gemtuzumab ozogamicin?
1,560 reports list Gemtuzumab ozogamicin as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 43 of them arrived in the latest 12 months. Another 271 list it only as a concomitant medication.
What reactions are recorded in Gemtuzumab ozogamicin reports?
febrile neutropenia (20.7%), sepsis (8.3%), venoocclusive liver disease (7.9%), thrombocytopenia (6.2%) and pyrexia (6.1%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Gemtuzumab ozogamicin was responsible.
How serious are the reports?
99.7% are marked serious by the reporter. Among the outcomes recorded, 32.4% of reports include death and 46.1% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.
Who files these reports?
physician (54%), other health professional (32.3%) and not given (9.8%). Most reports reach FDA through the manufacturer, which must forward reports it receives.
Are reports for Gemtuzumab ozogamicin rising?
43 reports in the 12 months to June 2026, down 27% from 59 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.
Do these reports show that Gemtuzumab ozogamicin was responsible for these reactions?
No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.
Is this a list of the side effects of Gemtuzumab ozogamicin?
No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.
How do I report an adverse event?
Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.
Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Gemtuzumab ozogamicin as a suspect or interacting product; reports listing it only as a concomitant medication (271) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.
Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.