Mekinist (trametinib)

Reviewed by: HU Medical Review Board | Last reviewed: February, 2022.

Mekinist® (trametinib) is used to treat certain kinds of advanced melanoma. Mekinist can be used alone or in combination with a drug called Tafinlar® (dabrafenib).1 Mekinist is used to treat melanoma with BRAF V600E or V600K mutation. Your doctor will test for BRAF mutation. Mekinist is not used for melanoma with a normal BRAF gene.

Mekinist is used when the melanoma:1

  • Cannot be removed with surgery (unresectable) or
  • Has spread to distant parts of the body (metastasized)
  • As adjuvant (additional) treatment for melanoma with BRAF V600E or V600K mutations after the melanoma has been surgically removed in people with disease in the lymph nodes (in combination with dabrafenib)

Mekinist does not come in generic form. Mekinist is similar to Cotellic® (cobimetinib), another drug that is approved to treat certain forms of unresectable or metastatic melanoma.

How does Mekinist work?

Mekinist is a type of medication called a kinase inhibitor. It works by blocking a protein called MEK that passes along signals for cell growth.

MEK is a protein in a pathway called MAPK (also called ERK). This pathway involves a chain of events that allow cells to grow and survive. Normally, there are mechanisms that turn each protein “on” and “off,” keeping the cell processes under control. However, approximately one-third of melanomas have mutations in the gene (instructions) for a protein called BRAF.2 These mutations cause BRAF to stay “on,” sending continuous signals resulting in uncontrolled cell growth.3

MEK comes after BRAF in this chain of events. Mekinist blocks MEK from working and stops the signal from continuing. Mekinist is called a targeted therapy because it targets one feature that makes cancer cells different from normal cells.

Tafinlar is a BRAF inhibitor. When Tafinlar and Mekinist are used together, they target the MAPK pathway at two points. This combination stops or slows the growth of melanomas with BRAF mutations better for some people than either drug alone.1

Receiving Mekinist

Before taking Mekinist, read the Medication Guide that comes in the package. Follow your doctor’s instructions for taking Mekinist.

Mekinist comes as a tablet that is taken by mouth. Patients should take their medication as prescribed by their doctor. Patients should talk to their doctor if they have any questions, or if they have questions regarding their trametinib regimen.

Based on your doctor’s instructions, you will typically continue trametinib until the cancer progresses or the side effects are unacceptable, but this may differ if your doctor is prescribing trametinib for adjuvant treatment.1

What are the side effects of Mekinist?

Taking Mekinist with Tafinlar can cause other cancers, such as other types of skin cancer known as cutaneous squamous cell carcinoma, basal cell carcinoma, keratoacanthoma, or new melanoma lesions.1 Possible signs of new cancers include: new wart, skin sore, reddish bump, or mole that changes in size or color (patients should tell their doctor if they notice any of these skin changes).

The most common side effects of Mekinist alone include diarrhea, rash, and swelling in the face, arms, or legs. Additional common side effects when trametinib is used with Dabrafenib for certain forms of melanoma include:1

  • Nausea and vomiting
  • Chills
  • Fever
  • Diarrhea
  • High blood pressure
  • Rash

Less common but serious side effects of Mekinist include:1

  • Bleeding problems in the brain or stomach
  • Blood clots
  • Heart problems
  • Eye problems
  • Lung problems
  • Inflammation or tears in the GI tract
  • Severe skin reaction
  • Increased blood sugar

Mekinist may make it difficult to get pregnant. If this is a concern for you, discuss this with your doctor.

This is not an exhaustive list of all potential side effects of trametinib. Talk to your healthcare provider or pharmacist for further information.

Who should not take Mekinist?

If you are pregnant, plan to become pregnant, or are breastfeeding or plan to breastfeed, talk with your doctor. Mekinist can cause harm to a developing fetus and should not be taken by women who are pregnant.1 While taking Mekinist, females who can become pregnant should use contraceptives during treatment and for a period of time after completing treatment (patients should discuss appropriate birth control methods, and how long they need to use them, with their doctor). Females should not breastfeed during Mekinist treatment and for a period of time following the final dose (patients should discuss breastfeeding considerations with their doctor).

While taking Mekinist, males with female partners who can become pregnant should always use a condom during sex throughout treatment and for a period of time after completing treatment (patients should discuss appropriate birth control methods, and how long they need to use them, with their doctor).

Tell your doctor about any medical conditions you have, especially:

  • Bleeding problems
  • Problems with blood clots
  • Heart problems
  • Eye problems
  • Lung or breathing problems
  • High blood pressure
  • Liver or kidney problems

What precautions are needed when taking Mekinist?

You will need regular skin exams while taking Mekinist with Tafinlar.1 Your doctor will do a skin exam before you start these medications. You will need skin exams every 2 months while taking these medications and for up to 6 months afterward. Your doctor will also look for non-skin cancers.

Before starting treatment with trametinib, patients should tell their doctor about all medications (prescription and over-the-counter), herbal supplements, and vitamins they are taking.

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