Crizotinib

ALK and ROS1 inhibitors
ALK and ROS1 inhibitors
High alert
An error with this medicine can cause serious harm: double checks and protocols are used.
Pregnancy: avoid
Avoid in pregnancy. Can harm the fetus: a pregnancy test is done before starting, effective contraception is used during treatment and for a time afterwards (by women and by men…

The first ALK inhibitor: an oral drug for ALK- or ROS1-positive lung cancer that also blocks MET. Watch the eyes, the pulse and the liver.

Updated Nov 1, 2026

Also called: PF-02341066

Quick facts

Group: ALK and ROS1 inhibitors
Target: ALK receptor tyrosine kinase (also ROS1 and MET)
Key effects: Visual disturbances · Nausea · Taste changes
Monitor: ALK or ROS1 test · Heart rate · Eye examination before
ATC: L01ED01

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

Mechanism of action

ALK receptor tyrosine kinase (also ROS1 and MET)Crizotinib

The figure shows crizotinib in the ATP pocket of the human ALK kinase domain.

Target in 3D: ALK receptor tyrosine kinase (also ROS1 and MET). PDB structure 2XP2 (RCSB PDB, public domain). View the structure at RCSB PDB

Crizotinib competes with ATP in the kinase domain of ALK, ROS1 and MET (hepatocyte growth factor receptor). In tumours where a rearrangement has fused ALK or ROS1 to another gene, the fused kinase is permanently active; blocking it stops the downstream growth and survival signals and the tumour shrinks. It was developed as a MET inhibitor and became the first drug approved for ALK-positive cancers.

A rearrangement fuses ALK or ROS1: the kinase is always on
Crizotinib fills the ATP pocket of ALK, ROS1 and MET
Growth and survival signals stop; the tumour shrinks

Indications

Metastatic non-small cell lung cancer that is ALK-positive or ROS1-positive. Lung cancer →
Relapsed or refractory ALK-positive systemic anaplastic large cell lymphoma in children and young adults. Non-Hodgkin lymphoma →
ALK-positive inflammatory myofibroblastic tumour that is unresectable, relapsed or refractory.

Adverse effects

Common

Visual disturbances: blurred or double vision, light sensitivity, flashes, floaters
Nausea, vomiting, diarrhoea or constipation
Swelling of the hands and legs (oedema)
Taste changes, decreased appetite, mouth sores
Numbness or tingling of the hands and feet (neuropathy)

Contraindications

Used with caution in long QT syndrome, slow heart rate or heart failure

Key interactions

Strong CYP3A4 inhibitors (clarithromycin, itraconazole, ketoconazole, ritonavir) and grapefruit: Raise its levels and its toxicity.
Strong CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, St John's wort): Lower its levels and can make it fail.
Drugs that slow the heart or prolong the QT interval: Additive bradycardia and arrhythmia risk.

What is monitored

ALK or ROS1 test of the tumour before starting
Liver tests before and during treatment
Heart rate, blood pressure and ECG
Eye examination before and during treatment

Administration and safety

Oral; swallowed whole, never split, crushed, chewed or opened.
With or without food; grapefruit and its juice are avoided.

Pregnancy and breastfeeding

Avoid in pregnancy. Can harm the fetus: a pregnancy test is done before starting, effective contraception is used during treatment and for a time afterwards (by women and by men with partners who could conceive), and breastfeeding is avoided.

Nursing care

Check pulse and blood pressure at each visit; report a slow or irregular pulse, dizziness or fainting.
Ask about vision changes and advise caution with driving until the patient knows how the drug affects them.
Teach to report cough, breathlessness or fever, and dark urine or right upper abdominal pain.
Confirm a negative pregnancy test before the first dose and teach contraception during treatment and afterwards.

Pharmacokinetics

Absorption: Oral capsules, with or without food.
Metabolism: Liver, mainly CYP3A4/5.

Test yourself

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

Which test must be positive before crizotinib is used in lung cancer?

An ALK or ROS1 rearrangement in the tumour.

A patient on crizotinib sees flashes of light and blurred images. What is this?

A typical visual disturbance of crizotinib; it is reported and an eye examination is arranged.

Which vital sign is checked closely on crizotinib, and why?

Heart rate, because it can cause bradycardia (and QT prolongation).

Add to my cards (3)

Connections

← Back to the class: ALK and ROS1 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: Crizotinib: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2022); Crizotinib - NCI (National Cancer Institute, 2022); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.