trametinib
Trametinib (Mekinist) is a MEK inhibitor used to treat certain melanomas, lung cancers, thyroid cancers, and other solid tumors with BRAF V600 mutations. It blocks the MEK protein, which is part of the same growth pathway as BRAF. It is used alone or in combination with dabrafenib.
This page is based on EMA and FDA prescribing information for trametinib tablets, cross-checked with DailyMed and MedlinePlus; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
If BRAF is the accelerator pedal in cancer cells, MEK is the transmission that carries that signal to the engine. Trametinib blocks the transmission, so even if the BRAF pedal is stuck down, the signal cannot reach the cell's growth machinery. When combined with dabrafenib, which blocks the BRAF pedal itself, the cancer cell is hit at two points in the same pathway.
In simple terms
Trametinib blocks the action of MEK proteins, which are part of a chain of signals that tell cancer cells to grow and divide. In certain cancers with a BRAF V600 mutation, this signal chain is stuck in the "on" position. By blocking MEK, trametinib helps stop the growth signals from reaching the cancer cells. It is used to treat certain types of melanoma, lung cancer, thyroid cancer, and other solid tumors. Trametinib is often combined with dabrafenib, which blocks BRAF (the protein above MEK in the pathway), to provide stronger control of cancer growth.
In depth
Trametinib is a selective inhibitor of MEK1 and MEK2 (MAPK/ERK kinases 1 and 2). MEK1/2 are dual-specificity kinases that phosphorylate and activate ERK1/2 in the RAF-MEK-ERK signaling cascade. In cells with BRAF V600 mutations, constitutive BRAF kinase activity leads to continuous MEK activation and uncontrolled cellular proliferation. Trametinib binds to MEK1/2 and inhibits their kinase activity, blocking downstream ERK signaling. As monotherapy, trametinib has activity in BRAF-mutant melanoma, but combination with dabrafenib (BRAF inhibitor) provides superior efficacy and delays resistance by achieving more complete pathway blockade. Trametinib is not active in cells with wild-type BRAF.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
If BRAF is the accelerator pedal in cancer cells, MEK is the transmission that carries that signal to the engine.
- Trametinib blocks the action of MEK proteins, which are part of a chain of signals that tell cancer cells to grow and divide.
- In certain cancers with a BRAF V600 mutation, this signal chain is stuck in the "on" position.
- Trametinib blocks the transmission, so even if the BRAF pedal is stuck down, the signal cannot reach the cell's growth machinery.
- When combined with dabrafenib, which blocks the BRAF pedal itself, the cancer cell is hit at two points in the same pathway.
Target: MEK1/MEK2 kinases
Dual-specificity kinases downstream of BRAF in the MAPK pathway; they relay growth signals from BRAF to ERK, driving cell proliferation and survival.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in European Union
EMA- Trametinib as monotherapy or in combination with dabrafenib is indicated for the treatment of adults and adolescents aged 12 years and older with unresectable or metastatic melanoma with a BRAF V600 mutation
- Adjuvant treatment of melanoma: Trametinib in combination with dabrafenib is indicated for the adjuvant treatment of adults and adolescents aged 12 years and older with Stage III melanoma with a BRAF V600 mutation, following complete resection
- Non-small cell lung cancer (NSCLC): Trametinib in combination with dabrafenib is indicated for the treatment of adults with advanced non-small cell lung cancer with a BRAF V600 mutation
- Differentiated thyroid cancer (DTC): Trametinib in combination with dabrafenib is indicated for the treatment of adult patients with locally advanced or metastatic differentiated thyroid cancer with a BRAF V600E mutation, refractory to or not eligible for radioactive iodine (RAI) who have progressed during or after prior systemic therapy
Approved uses in United States
FDA- MEKINIST is indicated as a single agent for the treatment of BRAF-inhibitor treatment-naïve patients with unresectable or metastatic melanoma with BRAF V600E or V600K mutations as detected by an FDA-approved test
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of patients with unresectable or metastatic melanoma with BRAF V600E or V600K mutations as detected by an FDA-approved test
- MEKINIST is indicated, in combination with dabrafenib, for the adjuvant treatment of patients with melanoma with BRAF V600E or V600K mutations, as detected by an FDA-approved test, and involvement of lymph node(s), following complete resection
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) with BRAF V600E mutation as detected by an FDA-approved test
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of patients with locally advanced or metastatic anaplastic thyroid cancer (ATC) with BRAF V600E mutation, as detected by an FDA-approved test, and with no satisfactory locoregional treatment options
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of adult and pediatric patients 1 year of age and older with unresectable or metastatic solid tumors with BRAF V600E mutation who have progressed following prior treatment and have no satisfactory alternative treatment options
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of pediatric patients 1 year of age and older with low-grade glioma (LGG) with a BRAF V600E mutation who require systemic therapy
Approved uses in United States
DailyMed- MEKINIST is indicated, as a single agent in BRAF-inhibitor treatment-naïve patients or in combination with dabrafenib, for the treatment of patients with unresectable or metastatic melanoma with BRAF V600E or V600K mutations, as detected by an FDA-approved test
- MEKINIST is indicated, in combination with dabrafenib, for the adjuvant treatment of patients with melanoma with BRAF V600E or V600K mutations as detected by an FDA-approved test, and involvement of lymph node(s), following complete resection
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) with BRAF V600E mutation as detected by an FDA-approved test
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of patients with locally advanced or metastatic anaplastic thyroid cancer (ATC) with BRAF V600E mutation, as detected by an FDA-approved test, and with no satisfactory locoregional treatment options
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of adult and pediatric patients 1 year of age and older with unresectable or metastatic solid tumors with BRAF V600E mutation who have progressed following prior treatment and have no satisfactory alternative treatment options
- MEKINIST is indicated, in combination with dabrafenib, for the treatment of pediatric patients 1 year of age and older with low-grade glioma (LGG) with a BRAF V600E mutation who require systemic therapy
Official sources
The statements on this page trace back to these records.
- Mekinist (trametinib) — Summary of product characteristics and package leaflet, English version
European Medicines Agency
- U.S. Food and Drug Administration: trametinib prescribing information
U.S. Food and Drug Administration
- DailyMed: trametinib labeling
DailyMed, U.S. National Library of Medicine
- MedlinePlus: trametinib
MedlinePlus, U.S. National Library of Medicine
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.