Posology : מינונים

4.2    Posology and method of administration

Treatment with VITRAKVI should be initiated by physicians experienced in the administration of anticancer therapies.

The presence of an NTRK gene fusion in a tumour specimen should be confirmed by a validated test prior to initiation of treatment with VITRAKVI.

Posology

Adults
The recommended dose in adults is 100 mg larotrectinib twice daily, until disease progression or until unacceptable toxicity occurs.

Paediatric population
Dosing in paediatric patients is based on body surface area (BSA). The recommended dose in paediatric patients is 100 mg/m2 larotrectinib twice daily with a maximum of 100 mg per dose until disease progression or until unacceptable toxicity occurs.


Missed dose
If a dose is missed, the patient should not take two doses at the same time to make up for a missed dose. Patients should take the next dose at the next scheduled time. If the patient vomits after taking a dose, the patient should not take an additional dose to make up for vomiting.

Dose modification
For all Grade 2 adverse reactions, continued dosing may be appropriate, though close monitoring to ensure no worsening of the toxicity is advised. Patients with Grade 2 ALT and/or AST increases, should be followed with serial laboratory evaluations every one to two weeks after the observation of Grade 2 toxicity until resolved to establish whether a dose interruption or reduction is required.

For Grade 3 or 4 adverse reactions:
-     VITRAKVI should be withheld until the adverse reaction resolves or improves to baseline or Grade 1. Resume at the next dose modification if resolution occurs within 4 weeks.
-     VITRAKVI should be permanently discontinued if an adverse reaction does not resolve within 4 weeks.

The recommended dose modifications for VITRAKVI for adverse reactions are provided in Table 1.

Table 1: Recommended dose modifications for VITRAKVI for adverse reactions Adult and
Paediatric patients with body
Dose modification     paediatric patients with body surface area less than 1.0 m2 surface area of at least 1.0 m2

First                                     75 mg twice daily                         75 mg/m2 twice daily 
Second                                    50 mg twice daily                         50 mg/m2 twice daily 
Third                                    100 mg once daily                         25 mg/m2 twice dailya a Paediatricpatients on 25 mg/m² twice daily should remain on this dose even if body surface area becomes greater 1.0 m² during the treatment. Maximum dose should be 25 mg/m² twice daily at the third dose modification.

VITRAKVI should be permanently discontinued in patients who are unable to tolerate VITRAKVI after three dose modifications.

Special populations

Elderly
No dose adjustment is recommended in elderly patients (see section 5.2).
Hepatic impairment
The starting dose of VITRAKVI should be reduced by 50% in patients with moderate (Child-Pugh B) to severe (Child-Pugh C) hepatic impairment. No dose adjustment is recommended for patients with mild hepatic impairment (Child-Pugh A) (see section 5.2).

Renal impairment
No dose adjustment is required for patients with renal impairment (see section 5.2).

Co-administration with strong CYP3A4 inhibitors
If co-administration with a strong CYP3A4 inhibitor is necessary, the VITRAKVI dose should be reduced by 50%. After the inhibitor has been discontinued for 3 to 5 elimination half-lives, VITRAKVI should be resumed at the dose taken prior to initiating the CYP3A4 inhibitor (see section 4.5).

Method of administration

VITRAKVI is for oral use.
VITRAKVI is available as a capsule or oral solution with equivalent oral bioavailability and may be used interchangeably.

The oral solution should be administered by mouth using an oral syringe of 1 mL or 5 mL volume or enterally by using a nasogastric feeding tube.
-     For doses below 1 mL a 1 mL oral syringe should be used. The calculated dose volume should be rounded to the nearest 0.1 mL.
-     For doses of 1 mL and higher a 5 mL oral syringe should be used. The dose volume should be calculated to the nearest 0.2 mL.
-     VITRAKVI should not be mixed with feeding formulas, if administered via nasogastric feeding tube. Mixing with the feeding formulas could lead to tube blockages.
-     For instructions for use of oral syringes and feeding tubes see section 6.6.

The oral solution can be taken with or without food but should not be taken with grapefruit or grapefruit juice.