Larotrectinib Dosage

Medically reviewed by Drugs.com. Last updated on Dec 29, 2023.

Applies to the following strengths: 25 mg; 100 mg; 20 mg/mL

Usual Adult Dose for Solid Tumors

Body surface area least 1 m2:
100 mg orally 2 times a day until disease progression or unacceptable toxicity

Comments:

Select patients for treatment with this drug based on the presence of a NTRK gene fusion in tumor specimens.

Use: For the treatment of adult patients with solid tumors that:

Have a neurotrophic receptor tyrosine kinase (NTRK) gene fusion without a known acquired resistance mutation
Are metastatic or where surgical resection is likely to result in severe morbidity
Have no satisfactory alternative treatments or that have progressed following treatment

Usual Pediatric Dose for Solid Tumors

28 days and older:

Body surface area at least 1 m2: 100 mg orally 2 times a day until disease progression or unacceptable toxicity
Body surface area less than 1 m2: 100 mg/m2 orally 2 times a day until disease progression or unacceptable toxicity.

Comments:

Select patients for treatment with this drug based on the presence of a NTRK gene fusion in tumor specimens.

Use: For the treatment of pediatric patients with solid tumors that:

Have a neurotrophic receptor tyrosine kinase (NTRK) gene fusion without a known acquired resistance mutation
Are metastatic or where surgical resection is likely to result in severe morbidity
Have no satisfactory alternative treatments or that have progressed following treatment

Renal Dose Adjustments

No adjustment recommended.

Liver Dose Adjustments

Mild hepatic impairment (Child-Pugh A): No adjustment recommended.
Moderate (Child-Pugh B) to severe (Child-Pugh C) hepatic impairment: Reduce the initial dose by 50%.

Dose Adjustments

Recommended Dose Modifications for Adverse Reactions:
FIRST DOSE REDUCTION:

Adult and pediatric patients with body surface area (BSA) of at least 1 m2: Reduce dose to 75 mg orally 2 times a day.
Pediatric patients with BSA less than 1 m2: Reduce dose to 75 mg/m2 orally 2 times a day.

SECOND DOSE REDUCTION:

Adult and pediatric patients with BSA of at least 1 m2: Reduce dose to 50 mg orally 2 times a day.
Pediatric patients with BSA less than 1 m2: Reduce dose to 50 mg/m2 orally 2 times a day.

THIRD DOSE REDUCTION:

Adult and pediatric patients with BSA of at least 1 m2: Reduce dose to 100 mg orally once a day.
Pediatric patients with BSA less than 1 m2: Reduce dose to 25 mg/m2 orally 2 times a day.

Permanently discontinue therapy in patients who are unable to tolerate this drug after 3 dose modifications.

Dose Modifications for Coadministration with Strong CYP450 3A4 Inhibitors:

Avoid coadministration of strong CYP450 3A4 inhibitors with this drug
If coadministration cannot be avoided, reduce the dose of this drug by 50%
After the inhibitor has been discontinued for 3 to 5 elimination half-lives, resume the dose of this drug taken prior to initiating the CYP450 3A4 inhibitor.

Dose Modifications for Coadministration with Strong CYP450 3A4 Inducers:

Avoid coadministration of strong CYP450 3A4 inducers with this drug.
If coadministration cannot be avoided, double the dose of this drug.
After the inducer has been discontinued for 3 to 5 elimination half-lives, resume the dose of this drug taken prior to initiating the CYP450 3A4 inducer.

Dosage Modifications for Adverse Reactions:
FOR GRADE 3 OR 4 ADVERSE REACTIONS:

Withhold therapy until adverse reaction resolves or improves to baseline or Grade 1.
Resume at the next dosage modification if resolution occurs within 4 weeks.
Permanently discontinue therapy if an adverse reaction does not resolve within 4 weeks.

Precautions

CONTRAINDICATIONS:

None

Safety and efficacy have not been established in patients less than 28 days old.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

This drug may be taken with or without food.
The capsule or oral solution may be used interchangeably.
Do not make up a missed dose within 6 hours of the next scheduled dose.
If vomiting occurs after taking a dose, take the next dose at the scheduled time.
Swallow capsules whole with water. Do not chew or crush.
Discard any unused oral solution remaining after 90 days of first opening the bottle.
Prior to preparing an oral dose for administration, refer to the instructions for use.

Storage requirements:

Store capsules at room temperature 20C to 25C (68F to 77F); temperature excursions between 15C and 30C (59F to 86F) are permitted.
Store the oral solution in the refrigerator at 2C to 8C (36F to 46F); do not freeze.

Monitoring:

Liver function tests.

Patient advice:

Read the approved patient labeling.
Notify your healthcare provider if you experience new or worsening

neurotoxicity.

Do not drive or operate hazardous machinery if you are experiencing neurologic adverse reactions.
This drug can harm a developing fetus.
Males and females of reproductive potential should use effective contraception during therapy with this drug and for at least 1 week after.
Inform your healthcare provider of a known or suspected pregnancy.