BRAF and MEK inhibitors
Oral drugs that block two steps of the MAPK pathway in BRAF V600-mutant melanoma, lung, thyroid and colorectal cancer; usually given as a pair.
What they are
BRAF inhibitors (vemurafenib, dabrafenib, encorafenib; suffix «-rafenib») block mutant BRAF; MEK inhibitors (trametinib, cobimetinib, binimetinib, selumetinib; suffix «-metinib») block the next kinase in the chain. Standard pairs are dabrafenib + trametinib, vemurafenib + cobimetinib and encorafenib + binimetinib.
Mechanism of action
The RAS–RAF–MEK–ERK (MAPK) pathway carries growth signals to the nucleus. About half of melanomas carry a BRAF mutation, most often V600E, which keeps BRAF active without any upstream signal. BRAF inhibitors block the mutant kinase; MEK inhibitors bind an allosteric pocket of MEK1/2, downstream. Single-agent resistance appears within months, often by reactivating the pathway; blocking two steps together delays resistance and lowers the rate of new skin squamous cell cancers seen with BRAF inhibitors alone.
Target: Mutant BRAF (V600E/K) and the MEK1/MEK2 kinases of the MAPK pathway
Drugs in this class
- DabrafenibAn oral inhibitor of mutant BRAF, paired with trametinib in BRAF V600 melanoma, lung and thyroid cancer. Watch fever…BRAF serine/threonine kinase (V600E/K mutants)
- EncorafenibA BRAF inhibitor given with binimetinib in BRAF V600 melanoma and lung cancer, and with cetuximab in BRAF V600E…BRAF serine/threonine kinase (V600E mutant), also wild-type BRAF and CRAF
- TrametinibThe first MEK inhibitor: an oral drug, usually with dabrafenib, for BRAF V600 melanoma, lung and thyroid cancer. Watch…MEK1 and MEK2 (MAP2K1/2) kinases
- BinimetinibA MEK1/2 inhibitor always given with encorafenib in BRAF V600 melanoma and lung cancer. Watch heart, eyes, muscles…MEK1 and MEK2 (MAP2K1/2) kinases
Others in the class
- vemurafenib
- cobimetinib
- selumetinib
Test yourself
Think of the answer, then tap the question to see it.
Why are a BRAF inhibitor and a MEK inhibitor given together?
Blocking two steps of the MAPK pathway delays resistance and reduces new skin cancers caused by BRAF inhibitors alone.
Which BRAF mutation is the classic target of these drugs?
V600E (valine 600 replaced by glutamic acid); V600K is also covered.
Which suffixes identify BRAF and MEK inhibitors?
«-rafenib» for BRAF and «-metinib» for MEK.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Dabrafenib Mesylate - NCI (National Cancer Institute, 2024).
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Representative model, for educational purposes only.