What the label lists and what reports show
Tremelimumab side effects
Tremelimumab's FDA label: “Most common adverse reactions (≥ 20%) of patients with uHCC are rash, diarrhea, fatigue, pruritus, musculoskeletal pain, and abdominal pain.” FAERS holds 4,216 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 diarrhoea (290 reports).
- No generic listed
Check it at the source: the tremelimumab FDA label on DailyMed (effective August 31, 2026); 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 IMJUDO?IMJUDO can cause serious side effects, including: See “What is the most important information I should know about IMJUDO?” The most common side effects of IMJUDO when used in combination with durvalumab in adults with uHCC include: • rash • diarrhea • feeling tired • itchiness • muscle or bone pain • stomach area (abdominal) pain The most common side effects of IMJUDO when used in combination with durvalumab and platinum-containing chemotherapy in adults with metastatic NSCLC include: • nausea • feeling tired or weak • muscle or bone pain • decreased appetite • rash • diarrhea Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of IMJUDO. Ask your healthcare provider or pharmacist for more information. Call your doctor for medical advice about side effects. […]
Source: FDA drug label, AstraZeneca Pharmaceuticals LP, effective August 31, 2026 (SPL set 6690679c-be2f-4588-a2e4-89fff74dd6be), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reactions (≥ 20%) of patients with uHCC are rash, diarrhea, fatigue, pruritus, musculoskeletal pain, and abdominal pain.
Table 7. Adverse Reactions (≥ 10%) in Patients with NSCLC Who Received IMJUDO in the POSEIDON Study
| Adverse Reaction | All Grades (%) | Grade 3 or 4 (%) | All Grades (%) | Grade 3 or 4 (%) |
|---|---|---|---|---|
| Cough/Productive Cough Includes cough and productive cough. | 12 | 0 | 8 | 0.3 |
| Nausea | 42 | 1.8 | 37 | 2.1 |
| Diarrhea | 22 | 1.5 | 15 | 1.5 |
| Constipation | 19 | 0 | 24 | 0.6 |
| Vomiting | 18 | 1.2 | 14 | 1.5 |
| Stomatitis Includes mucosal inflammation and stomatitis. | 10 | 0 | 6 | 0.3 |
| Hypothyroidism Includes blood thyroid stimulating hormone increased and hypothyroidism. | 13 | 0 | 2.1 | 0 |
| Rash Includes eczema, erythema, dermatitis, drug eruption, erythema multiforme,… | 27 | 2.4 | 10 | 0.6 |
| Alopecia | 10 | 0 | 6 | 0 |
| Pruritus | 11 | 0 | 4.5 | 0 |
| Fatigue/Asthenia Includes asthenia and fatigue. | 36 | 5 | 32 | 4.5 |
| Pyrexia Includes body temperature increased, hyperpyrexia, hyperthermia, and pyrexia. | 19 | 0 | 8 | 0 |
| Edema Includes face edema, localized edema, and edema peripheral. | 10 | 0 | 10 | 0.6 |
| Musculoskeletal Pain Includes arthralgia, arthritis, back pain, bone pain,… | 29 | 0.6 | 22 | 1.5 |
| Decreased appetite | 28 | 1.5 | 25 | 1.2 |
| Pneumonia Includes lower respiratory tract infection, pneumocystis jirovecii pneumonia,… | 17 | 8 | 12 | 4.2 |
| Upper respiratory tract infections Includes laryngitis, nasopharyngitis, pharyngitis,… | 15 | 0.6 | 9 | 0.9 |
| Headache Includes headache, migraine. | 11 | 0 | 8 | 0.6 |
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 adverse reactions are discussed in greater detail in other sections of the labeling. • Immune-Mediated Adverse Reactions [see Warnings and Precautions (5.1) ]. • Infusion-Related Reactions [see Warnings and Precautions (5.2) ]. Most common adverse reactions (≥ 20%) of patients with uHCC are rash, diarrhea, fatigue, pruritus, musculoskeletal pain, and abdominal pain. Most common laboratory abnormalities (≥ 40%) of patients with uHCC are AST increased, ALT increased, hemoglobin decreased, sodium decreased, bilirubin increased, alkaline phosphatase increased, and lymphocytes decreased. ( 6.1 ) Most common adverse reactions (≥ 20%) of patients with metastatic NSCLC were nausea, fatigue, musculoskeletal pain, decreased appetite, rash, and diarrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact AstraZeneca at 1-800-236-9933 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 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. The data described in the Warnings and Precautions reflect exposure to IMJUDO 300 mg in combination with durvalumab 1,500 mg in 388 patients in HIMALAYA. …
Source: FDA drug label, AstraZeneca Pharmaceuticals LP, effective August 31, 2026 (SPL set 6690679c-be2f-4588-a2e4-89fff74dd6be), via openFDA; the full label on DailyMed
What do FAERS reports show?
4,216 reports list tremelimumab among the medicines taken, each a report of something that happened, not proof the medicine caused it; 1,203 are coded as a death and 2,043 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 23 reactions below, 16 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?
- Tremelimumab: 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