Mektovi (Binimetinib)

• Mektovi is a targeted MEK inhibitor used in the management of BRAF‑mutated melanoma.
• Unresectable or metastatic melanoma with BRAF V600E/K mutation: reduces tumor cell proliferation and can improve progression‑free survival, especially when combined with encorafenib.

• Binimetinib selectively inhibits the serine‑threonine kinases MEK1 and MEK2, which are key components of the MAPK/ERK signaling cascade. By blocking MEK activity, the drug prevents phosphorylation of downstream ERK proteins, thereby interrupting cellular signals that drive uncontrolled proliferation of tumor cells bearing BRAF V600 mutations.

Common and serious adverse reactions have been reported with binimetinib therapy.

Common Side Effects

• Diarrhea: loose stools occurring during treatment.
• Nausea: feeling of sickness or urge to vomit.
• Fatigue: persistent tiredness not relieved by rest.
• Rash: skin irritation or redness.
• Elevated liver enzymes: increase in ALT/AST levels.
• Edema: swelling of extremities.

Serious or Rare Side Effects

• Interstitial lung disease: inflammation of lung tissue.
• Severe hepatic toxicity: significant liver injury.
• Cardiomyopathy: weakening of heart muscle function.
• Retinal disorders: vision changes or eye inflammation.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.

Before and during treatment, several safety considerations should be observed.

• Baseline assessment: obtain liver function tests and cardiac evaluation before initiating therapy.
• Monitoring: perform regular liver enzyme and ECG assessments during treatment.
• Pregnancy: avoid use in pregnant women; discuss contraception with women of childbearing potential.
• Concomitant medications: review for potential CYP3A4 interactions before prescribing.
• Vision: advise patients to report visual disturbances promptly.
• Store at ambient temperature: keep tablets below 25 °C in the original container, protected from moisture and light.

Binimetinib may interact with other medicines, requiring attention to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may markedly reduce binimetinib exposure.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): can increase drug levels and toxicity.

Moderate Interactions (Monitor Closely)

• Moderate CYP3A4 inhibitors (e.g., erythromycin, fluconazole): may require dose adjustment.
• Anticoagulants (e.g., warfarin): monitor INR as binimetinib may affect metabolism.
• QT‑prolonging agents: observe cardiac rhythm due to potential additive effects.