Binimetinib
BRAF and MEK inhibitors
BRAF and MEK inhibitorsHigh 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…
A MEK1/2 inhibitor always given with encorafenib in BRAF V600 melanoma and lung cancer. Watch heart, eyes, muscles, liver and clots.
Quick facts
- Group
- BRAF and MEK inhibitors
- Target
- MEK1 and MEK2 (MAP2K1/2) kinases
- Used for
- BRAF V600E/K unresectable
- Key effects
- Fatigue · Nausea · Dizziness
- Monitor
- Heart function before · Eye examinations
- ATC
- L01EE03
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows binimetinib in the allosteric pocket of human MEK1, crystallised in complex with BRAF.
Binimetinib inhibits MEK1 and MEK2 downstream of BRAF, so ERK is not activated. With the BRAF inhibitor encorafenib it blocks two steps of the MAPK pathway in BRAF V600-mutant tumours.
- Inhibits MEK1 and MEK2 below BRAF
- ERK stays inactive: the growth signal stops
- Always paired with encorafenib
Indications
- BRAF V600E/K unresectable or metastatic melanoma, with encorafenib. Melanoma →
- BRAF V600E metastatic non-small cell lung cancer in adults, with encorafenib. Lung cancer →
Adverse effects
Common
- Fatigue
- Nausea, vomiting, diarrhoea, constipation, abdominal pain
- Dizziness
Contraindications
- No absolute contraindications in the label apart from hypersensitivity; see the warnings
Key interactions
- Encorafenib
- Intended partner; binimetinib is not used alone.
- Anticoagulants and antiplatelet drugs
- Add to its bleeding risk.
What is monitored
- Heart function before and during treatment
- Eye examinations
- Liver tests and muscle symptoms
- Signs of thrombosis or bleeding
Administration and safety
- Oral tablets twice daily, with or without food, together with encorafenib.
- Check that both drugs of the pair are on the order and dispensed.
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
- Teach to report a fast or pounding heartbeat, ankle swelling or breathlessness.
- Teach to report vision changes, muscle pain or weakness, and dark urine.
- Teach the signs of a leg clot or pulmonary embolism, and of bleeding.
- Confirm a negative pregnancy test before the first dose and teach contraception during treatment and afterwards.
Pharmacokinetics
- Absorption
- Oral tablets, twice daily, with or without food.
- Elimination
- Exposure rises with moderate to severe liver impairment; kidney function does not change it.
- Half-life
- About 3.5 hours.
Test yourself
Think of the answer, then tap the question to see it.
With which drug is binimetinib always given?
Encorafenib, a BRAF inhibitor.
Which step of the MAPK pathway does binimetinib block?
MEK1/2, between BRAF and ERK.
A patient on binimetinib has muscle pain and dark urine. What is suspected?
Drug-induced muscle injury; it is reported at once.
Connections
← Back to the class: BRAF and MEK 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: Binimetinib: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2024); Binimetinib - NCI (National Cancer Institute, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.