Pharmacologic class (EPC) · 2 drug pages

CD33-directed immunoconjugate: adverse event reports filed with FDA

3,378 reports list a drug in this class as a suspect or interacting product, 2004–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

3,378
reports across the class: 0% of all reports; 76
reports, 12 months to June 2026: 121 in the 12 months before; 97.3%
marked serious by the reporter: 57.4% across all reports; 2
drugs with a page: brand and generic names counted separately

CD33-directed immunoconjugate is a pharmacologic class (an FDA Established Pharmacologic Class) with 2 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 3,378 adverse event reports received by FDA, 0% of the database, from January 2004 to June 2026.

76 reports arrived in the 12 months to June 2026, down 37% from 121 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 97.3% of the class's reports are marked serious, 31.9% record death among the outcomes and 48.3% record hospitalisation, as reported.

Across the class the reactions recorded most often are febrile neutropenia (19.4%), pyrexia (9.1%) and sepsis (8.5%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is 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."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
MylotargGemtuzumab ozogamicin	brand	1,818	33	95.2%	Febrile neutropenia
Gemtuzumab ozogamicin	generic	1,560	43	99.7%	Febrile neutropenia

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."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Febrile neutropeniafever with low white blood cells19.4%657
Pyrexiafever9.1%306
Sepsisa severe body-wide response to infection8.5%286
Venoocclusive liver disease7.4%250
Platelet count decreasedlow platelet count6.6%223
Thrombocytopenialow platelets6.2%211
Neutropenialow neutrophils, a type of white blood cell5.3%180
White blood cell count decreasedlow white cell count5.2%176
Pneumonialung infection4.9%166
Aspartate aminotransferase increasedraised liver enzyme (AST)4.8%162
Alanine aminotransferase increasedraised liver enzyme (ALT)4.4%147
Chillschills or shivering4.4%147
Hypotensionlow blood pressure4%134
Disease progressionthe disease advanced3.8%129
Acute myeloid leukaemia3.7%126
Infusion related reactiona reaction during or soon after an infusion3.6%123
Blood bilirubin increased3.4%114
Anaemialow red blood cells3.2%107
Haemoglobin decreasedlow haemoglobin3.1%104
Weight increasedweight gain3%103
Pancytopenialow counts of all blood cells3%102
Blood alkaline phosphatase increased3%100
Drug ineffectivethe medicine did not work as expected2.9%99
Neutrophil count decreased2.9%97
Septic shockshock arising from infection2.9%97

Solid bar: share of all class reports. Hollow bar: the median share across the 2 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death31.9%1,076

Life-threatening20%676

Hospitalisation (initial or prolonged)48.3%1,633

Disability1.2%40

Congenital anomaly0%0

Other serious47.3%1,598

Not serious2.7%92

Patient age

Under 21.1%37

2 to 113.8%128

12 to 173.6%120

18 to 4413%439

45 to 6425.3%853

65 to 7414.1%475

75 and over5.8%195

Age not given33.5%1,131

Who reported

Physician47.6%1,608

Pharmacist4%134

Other health professional25.5%863

Lawyer0%0

Consumer or non-health professional3.8%130

Not given19%643

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about CD33-directed immunoconjugate reports

Which drugs are in the CD33-directed immunoconjugate class on this site?

Mylotarg and Gemtuzumab ozogamicin. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

3,378 reports through June 2026, 76 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

febrile neutropenia (19.4%), pyrexia (9.1%), sepsis (8.5%), venoocclusive liver disease (7.4%) and platelet count decreased (6.6%).

Can the members table be used to rank the drugs?

No. 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." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. 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 class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. 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.