Trametinib (Mekinist) is a kinase inhibitor indicated for the treatment of patients with unresectable or metastatic melanoma that is confirmed to harbor BRAF V600E or V600K mutations by an FDA-approved test. As a targeted therapy, its rational use must strictly adhere to the principle of individualization, covering aspects such as initial dose selection, management of adverse reactions, and dosage adjustments for special populations.

Dosage and Administration of Trametinib (Mekinist)

Dosage and Administration Method

Recommended Dose:2 mg orally once daily until disease progression or unacceptable toxicity occurs.

Dosing Time:Administer on an empty stomach, i.e., at least 1 hour before a meal or 2 hours after a meal.

Missed Dose Management:If a dose is missed, take it as soon as the patient remembers. However, if it is within 12 hours of the next scheduled dose, skip the missed dose and resume the regular dosing schedule. Do not take a double dose to make up for the missed one.

Dosage Adjustments of Trametinib (Mekinist)

Cutaneous Toxicity

Grade 2 Rash:Reduce the dose by 0.5 mg, or discontinue treatment if the original daily dose is 1 mg.

Intolerable Grade 2 Rash or Grade 3/4 Rash

Withhold treatment for up to 3 weeks. If improvement occurs within 3 weeks, resume treatment at a dose reduced by 0.5 mg; otherwise, discontinue treatment permanently.

Cardiac Toxicity

Left Ventricular Ejection Fraction (LVEF) Decrease:If the absolute decrease in LVEF from baseline is ≥10% and the value falls below the lower limit of normal, withhold treatment for up to 4 weeks.

If recovery occurs within 4 weeks, continue treatment at a reduced dose. Permanently discontinue treatment if symptomatic heart failure develops or LVEF remains persistently abnormal.

Ocular Adverse Reactions

Retinal Pigment Epithelial Detachment (RPED):Withhold treatment for up to 3 weeks; resume at a reduced dose if improvement occurs.

Permanently discontinue treatment if no improvement is observed within 3 weeks or if retinal vein occlusion occurs.

Pulmonary and Other Toxicities

Interstitial Lung Disease (ILD):Discontinue treatment permanently and immediately upon confirmation of diagnosis.

Grade 3 Non-cutaneous Adverse Reactions:Withhold treatment for up to 3 weeks; resume at a reduced dose after improvement.

Permanently discontinue treatment for Grade 4 reactions.

Use in Special Populations

Pregnant Women

Trametinib has embryo-fetal toxicity and may cause spontaneous abortion or fetal harm.

Women of childbearing potential must use highly effective contraceptive measures during treatment and for 4 months after discontinuing trametinib. Immediately discontinue treatment and assess the risk if pregnancy occurs.

Lactating Women

Trametinib may be excreted in human milk, posing potential risks to infants. It is recommended to discontinue breastfeeding during treatment.

Patients with Hepatic or Renal Impairment

Mild Hepatic Impairment or Mild to Moderate Renal Impairment:No dosage adjustment is required.

Moderate to Severe Hepatic Impairment or Severe Renal Impairment:The safety and efficacy have not been clearly established; careful evaluation is needed before administration.