Cabozantinib is a multi-target tyrosine kinase inhibitor that is suitable for the treatment of various cancers. The dosage should be adjusted according to the indications, and serious side effects should be monitored. The following provides a detailed explanation from three aspects: indications, dosage regimen, and side effects to help patients safely use medication.

1 Scope of indications

Cabozantinib has been approved for use in medullary thyroid cancer, renal cell carcinoma, hepatocellular carcinoma, and differentiated thyroid cancer in children. There are differences in dosage forms for different indications. Capsules are used for medullary thyroid cancer, while tablets are commonly used for other indications. Treatment should continue until disease progression or intolerable toxicity occurs.

2-dose plan

(1) Adult standard dose

Thyroid medullary carcinoma: 140mg per day (1 80mg capsule+3 20mg capsules). The monotherapy for renal cell carcinoma is 60mg per day, and when combined with nivolumab, it is reduced to 40mg. The fixed dose for hepatocellular carcinoma is 60mg per day, which should be taken on an empty stomach.

(2) Dose adjustment for children

Individuals aged 12 and above with a body surface area of ≥ 1.2 square meters should take 60mg per day, while those with a body surface area of<1.2 square meters should take 40mg. Dynamic adjustments should be made based on changes in body surface area, and growth and development indicators should be evaluated every 2-3 months during treatment.

(3) Adjustment of liver and kidney dysfunction

The thyroid indication for patients with mild to moderate liver damage is reduced to 80mg/day, and the renal cancer indication is 40mg/day. Prohibited for severe liver damage. Severe renal insufficiency only requires caution and dose adjustment is not necessary.

3 Side Effect Management

(1) Serious reactions requiring immediate medical attention

Including perforation/fistula, major bleeding, hypertensive crisis, liver toxicity (ALT/AST>10x ULN), etc. Emergency treatment and permanent discontinuation of medication are required when vomiting blood, severe headache, jaundice, or wounds do not heal.

(2) Common tolerable side effects

Diarrhea (57%), hand foot syndrome (50%), and fatigue (41%) are mostly classified as grades 1-2. Suggest targeted treatment, such as using antidiarrheal drugs and moisturizers, adjusting the dosage instead of immediately stopping the medication.

(3) Special monitoring requirements

Blood pressure, urine protein, and thyroid function should be checked before treatment. Monitor blood pressure weekly during the first month of medication and have monthly follow-up thereafter. During combined immunotherapy, it is necessary to strengthen liver enzyme monitoring (once every 2 weeks).

(4) Principle of dose adjustment

For the first occurrence of grade 2 adverse reactions, medication should be suspended and the original dose should be reduced by 20mg upon recovery. For grade 3 events, 40mg should be reduced. For recurrence of the same grade 3 event or grade 4 toxicity, permanent discontinuation of medication is required.