[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Immune checkpoint inhibitors](https://durgical.com/en/pharmacology/classes/immune-checkpoint-inhibitors/) › Ipilimumab

# Ipilimumab

## Immune checkpoint inhibitors?

Immune checkpoint inhibitors

## High alert?

An error with this medicine can cause serious harm: double checks and protocols are used.

Anti-CTLA-4 antibody for melanoma, often with nivolumab. It causes more immune toxicity (colitis, hypophysitis) than anti-PD-1 drugs.

Updated Nov 1, 2026

Also called: anti-CTLA-4 antibody

## Quick facts

**Group**
[Immune checkpoint inhibitors](https://durgical.com/en/pharmacology/classes/immune-checkpoint-inhibitors/)

**Target**
Cytotoxic T-lymphocyte antigen 4 (CTLA-4)

**Used for**
Advanced melanoma · With nivolumab · With nivolumab

**Key effects**
Rash · Diarrhoea · Fatigue

**Monitor**
Thyroid function · Glucose · Stool frequency

**ATC**
L01FX04

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Cytotoxic T-lymphocyte antigen 4 (CTLA-4)**Ipilimumab

ⓘ The crystal shows human CTLA-4 bound by the ipilimumab Fab, which covers the surface CTLA-4 uses to bind B7 ligands.

**Target in 3D:** Cytotoxic T-lymphocyte antigen 4 (CTLA-4). PDB structure 5TRU (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/5TRU) · Drag to rotate · pinch to zoom

CTLA-4 on T cells binds the B7 ligands of antigen-presenting cells and dampens T-cell priming in lymph nodes. Ipilimumab blocks CTLA-4: more T cells are primed, the T-cell repertoire widens and regulatory T cells are less able to suppress the response. The broader, stronger activation explains both durable responses in melanoma and frequent immune toxicity in skin, gut, liver and endocrine glands.

- CTLA-4 binds B7 and brakes T-cell priming
- Ipilimumab blocks CTLA-4 binding to B7
- More T cells are primed; regulatory T cells weaken
- Broad antitumour response, frequent immune toxicity

## Indications

- Advanced melanoma, alone or with nivolumab, and after surgery to prevent recurrence. [Melanoma →](https://durgical.com/en/conditions/melanoma/)
- With nivolumab: renal cell carcinoma. [Renal cell carcinoma →](https://durgical.com/en/conditions/renal-cell-carcinoma/)
- With nivolumab: colorectal cancer with high microsatellite instability. [Colorectal cancer →](https://durgical.com/en/conditions/colorectal-cancer/)
- With nivolumab: hepatocellular carcinoma. [Hepatocellular carcinoma →](https://durgical.com/en/conditions/hepatocellular-carcinoma/)
- With nivolumab: non-small cell lung cancer and malignant pleural mesothelioma. [Lung cancer →](https://durgical.com/en/conditions/lung-cancer/)
- Malignant pleural mesothelioma, with nivolumab. [Malignant pleural mesothelioma →](https://durgical.com/en/conditions/malignant-pleural-mesothelioma/)

## Adverse effects

### Common

- Rash, itching, vitiligo
- Diarrhoea
- Fatigue
- Nausea, decreased appetite

### Serious (rare, important)

- Immune-mediated pneumonitis
- Immune-mediated colitis
- Immune-mediated hepatitis
- Endocrinopathies: hypophysitis, thyroiditis, adrenal insufficiency, type 1 diabetes
- Immune-mediated nephritis
- Severe skin reactions
- Myocarditis, myositis and neurological reactions (myasthenia, Guillain-Barré syndrome)
- Infusion reactions

## Contraindications

- Previous severe immune-mediated reaction to a checkpoint inhibitor (generally not re-exposed)
- Caution: active autoimmune disease, organ or allogeneic stem-cell transplant

## Key interactions

**Systemic corticosteroids and other immunosuppressants**
Used to treat moderate to severe immune-mediated reactions; they damp the immune response.

**Nivolumab**
Added efficacy and more frequent immune toxicity, including rare fatal myocarditis.

## What is monitored

- Thyroid function (TSH) before starting and regularly
- Liver tests and creatinine before each dose
- Glucose; cortisol if fatigue or low blood pressure
- Stool frequency, cough and breathlessness at each visit
- Signs of myocarditis (chest pain, palpitations) and muscle weakness

## Administration and safety

- Intravenous infusion only, never as a push or bolus, through a line as the product instructions specify.
- Look-alike names: the -mab checkpoint inhibitors (nivolumab, pembrolizumab, atezolizumab, cemiplimab, ipilimumab) are checked by full name; products combined with hyaluronidase for subcutaneous use are not interchangeable with the intravenous ones.
- Watch for infusion reactions (chills, fever, rash, breathlessness) during the infusion.

## Pregnancy and breastfeeding

Blocking PD-1/PD-L1 or CTLA-4 can harm the fetus (IgG antibodies cross the placenta); effective contraception is used during treatment and for months after, and breastfeeding is avoided.

## Nursing care

- Before each dose, ask about diarrhoea, cough, rash, headache, fatigue, dizziness, thirst or passing more urine, and review thyroid, liver, kidney and glucose results.
- Teach the patient that side effects can start weeks or months after a dose, even after treatment ends, and must be reported early.
- Teaching: report diarrhoea or blood in the stool, new cough or breathlessness, yellow skin, severe headache, extreme tiredness, chest pain or muscle weakness at once.
- Make sure the patient carries information that they receive immunotherapy, for any emergency visit.

## Pharmacokinetics

**Absorption**
Intravenous infusion.

**Elimination**
Broken down like natural IgG.

**Half-life**
About 15 days.

## Memory aid

«CTLA-4 = Control in the Lymph node»: ipilimumab acts early (priming), so its toxicity is broad: Colitis, Hypophysitis, Hepatitis, skin.

## Test yourself

Think of the answer, then tap the question to see it.

## Where in the immune response does ipilimumab mainly act?

At T-cell priming in lymph nodes, by blocking the binding of CTLA-4 to B7.

## A patient on ipilimumab has headache, fatigue and low sodium. Which immune toxicity is suspected?

Hypophysitis (inflammation of the pituitary).

## Which causes more immune-related toxicity overall: anti-CTLA-4 or anti-PD-1?

Anti-CTLA-4 (ipilimumab).

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/ipilimumab/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**High alert**
An error with this medicine can cause serious harm: double checks and protocols are used.

## Connections

## Related drugs 2

- [Nivolumab](https://durgical.com/en/pharmacology/nivolumab/)
- [Pembrolizumab](https://durgical.com/en/pharmacology/pembrolizumab/)

## Related conditions 6

- [Melanoma](https://durgical.com/en/conditions/melanoma/)
- [Renal cell carcinoma](https://durgical.com/en/conditions/renal-cell-carcinoma/)
- [Colorectal cancer](https://durgical.com/en/conditions/colorectal-cancer/)
- [Hepatocellular carcinoma](https://durgical.com/en/conditions/hepatocellular-carcinoma/)
- [Lung cancer](https://durgical.com/en/conditions/lung-cancer/)
- [Malignant pleural mesothelioma](https://durgical.com/en/conditions/malignant-pleural-mesothelioma/)

[← Back to the class: Immune checkpoint inhibitors](https://durgical.com/en/pharmacology/classes/immune-checkpoint-inhibitors/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Ipilimumab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a611023.html) (MedlinePlus (U.S. National Library of Medicine), 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L01FX04) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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