What the label lists and what reports show
Blinatumomab side effects
Blinatumomab's FDA label: “The most common adverse reactions (≥ 20%) are pyrexia, infusion-related reactions, headache, infection, musculoskeletal pain, neutropenia, nausea, anemia, thrombocytopenia, and diarrhea.” FAERS holds 10,373 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is pyrexia (1,160 reports).
- No generic listed
- Boxed warning
Check it at the source: the blinatumomab FDA label on DailyMed (effective April 14, 2026, Amgen, Inc); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of BLINCYTO?BLINCYTO may cause serious side effects, including: See “ What is the most important information I should know about BLINCYTO? ” Infections. BLINCYTO may cause life-threatening infections that may lead to death. Tell your healthcare provider right away if you develop any signs or symptoms of an infection. Tumor Lysis Syndrome (TLS). TLS is caused by the fast breakdown of cancer cells. TLS can be life-threatening and may lead to death. Tell your healthcare provider right away if you have any symptoms of TLS during treatment with BLINCYTO, including: nausea and vomiting confusion shortness of breath irregular heartbeat dark or cloudy urine reduced amount of urine unusual tiredness muscle cramps Low white blood cell counts (neutropenia). Neutropenia is common with BLINCYTO treatment and may sometimes be life-threatening. Low white blood cell counts can increase your risk of infection. […]
Source: FDA drug label, Amgen, Inc, effective April 14, 2026 (SPL set 38b482a8-960b-4591-9857-5031ecb830aa), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse reactions (≥ 20%) are pyrexia, infusion-related reactions, headache, infection, musculoskeletal pain, neutropenia, nausea, anemia, thrombocytopenia, and diarrhea.
Table 6. Adverse Reactions Occurring at ≥ 10% Incidence for Any Grade or ≥ 5% Incidence for Grade 3 or Higher in BLINCYTO-treated Adult Patients with MRD-Positive B-cell Precursor ALL
| Reaction | Adverse Reaction Any Grade Grading based on NCI Common Terminology Criteria for Adverse Events (CTCAE)… | BLINCYTO (N = 137) Grade ≥ 3 n (%) |
|---|---|---|
| Neutropenia Neutropenia includes febrile neutropenia, neutropenia, and neutrophil count… | 21 (15) | 21 (15) |
| Leukopenia Leukopenia includes leukopenia and white blood cell count decreased. | 19 (14) | 13 (9) |
| Thrombocytopenia Thrombocytopenia includes platelet count decreased and thrombocytopenia. | 14 (10) | 8 (6) |
| Arrhythmia Arrhythmia includes bradycardia, sinus arrhythmia, sinus bradycardia, sinus… | 17 (12) | 3 (2) |
| Pyrexia Pyrexia includes body temperature increased and pyrexia. | 125 (91) | 9 (7) |
| Chills | 39 (28) | 0 (0) |
| Infections - pathogen unspecified | 53 (39) | 11 (8) |
| Infusion-related reaction Infusion-related reaction is a composite term that includes the… | 105 (77) | 7 (5) |
| Decreased immunoglobulins Decreased immunoglobulins includes blood immunoglobulin A… | 25 (18) | 7 (5) |
| Weight increased | 14 (10) | 1 (< 1) |
| Hypertransaminasemia Hypertransaminasemia includes alanine aminotransferase increased,… | 13 (9) | 9 (7) |
| Back pain | 16 (12) | 1 (< 1) |
| Headache May represent ICANS. | 54 (39) | 5 (4) |
| Tremor , Tremor includes essential tremor, intention tremor, and tremor. | 43 (31) | 6 (4) |
| Aphasia | 16 (12) | 1 (< 1) |
| Dizziness | 14 (10) | 1 (< 1) |
| Encephalopathy , Encephalopathy includes cognitive disorder, depressed level of… | 14 (10) | 6 (4) |
| Insomnia , Insomnia includes initial insomnia, insomnia, and terminal insomnia. | 24 (18) | 1 (< 1) |
| Cough | 18 (13) | 0 (0) |
| Rash Rash includes dermatitis contact, eczema, erythema, rash, and rash maculopapular. | 22 (16) | 1 (< 1) |
| Hypotension | 19 (14) | 1 (< 1) |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described elsewhere in the labeling: Cytokine Release Syndrome [see Warnings and Precautions (5.1) ] Neurological Toxicities, including Immune Effector Cell-Associated Neurotoxicity Syndrome [see Warnings and Precautions (5.2) ] Infections [see Warnings and Precautions (5.3) ] Tumor Lysis Syndrome [see Warnings and Precautions (5.4) ] Neutropenia and Febrile Neutropenia [see Warnings and Precautions (5.5) ] Effects on Ability to Drive and Use Machines [see Warnings and Precautions (5.6) ] Elevated Liver Enzymes [see Warnings and Precautions (5.7) ] Pancreatitis [see Warnings and Precautions (5.8) ] Leukoencephalopathy [see Warnings and Precautions (5.9) ] The most common adverse reactions (≥ 20%) are pyrexia, infusion-related reactions, headache, infection, musculoskeletal pain, neutropenia, nausea, anemia, thrombocytopenia, and diarrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Amgen Inc. at 1-800-77-AMGEN (1-800-772-6436) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Source: FDA drug label, Amgen, Inc, effective April 14, 2026 (SPL set 38b482a8-960b-4591-9857-5031ecb830aa), via openFDA; the full label on DailyMed
What do FAERS reports show?
10,373 reports list blinatumomab among the medicines taken, each a report of something that happened, not proof the medicine caused it; 1,893 are coded as a death and 2,787 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 21 reactions below, 13 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Blinatumomab: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions