Overview
11 DESCRIPTION Larotrectinib is a kinase inhibitor. VITRAKVI (larotrectinib) capsules and oral solution are formulated using larotrectinib sulfate. The molecular formula for larotrectinib sulfate is C 21 H 24 F 2 N 6 O 6 S and the molecular weight is 526.51 g/mol for the sulfate salt and 428.44 g/mol for the free base.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Larotrectinib is an inhibitor of the tropomyosin receptor kinases (TRK), TRKA, TRKB, and TRKC. In a broad panel of purified enzyme assays, larotrectinib inhibited TRKA, TRKB, and TRKC with IC 50 values between 5-11 nM. One other kinase TNK2 was inhibited at approximately 100-fold higher concentration. TRKA, B, and C are encoded by the genes NTRK1, NTRK2, and NTRK3. Chromosomal rearrangements involving in-frame fusions of these genes with various partners can result in constitutively-activated chimeric TRK fusion proteins that can act as an oncogenic driver, promoting cell proliferation and survival in tumor cell lines.
Indications
- 1 INDICATIONS AND USAGE VITRAKVI is indicated for the treatment of adult and 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, and have no satisfactory alternative treatments or that have progressed following treatment. Select patients for therapy based on an FDA-approved test [see Dosage and Administration (2.1) ].
Common Doses
- 100 mg
- 75 mg
- 50 mg
- 25 mg
Dosage
2 DOSAGE AND ADMINISTRATION Select patients for treatment with VITRAKVI based on the presence of a NTRK gene fusion ( 2.1 , 14 ). Recommended Dosage in Adult and Pediatric Patients with Body Surface Area of 1 Meter-Squared or greater: 100 mg orally twice daily ( 2.2 ) Recommended Dosage in Pediatric Patients with Body Surface Area of Less Than 1 Meter-Squared: 100 mg/m 2 orally twice daily ( 2.2 ) 2.1 Patient Selection Select patients for treatment with VITRAKVI based on the presence of a NTRK gene fusion in tumor specimens [see Clinical Studies (14) ] .
Contraindications
- 4 CONTRAINDICATIONS None. None. ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Central Nervous System Effects [see Warnings and Precautions (5.1) ] Skeletal Fractures [see Warnings and Precautions (5.2) ] Hepatotoxicity [see Warnings and Precautions (5.3) ] The most common (≥ 20%) adverse reactions, including laboratory abnormalities, with VITRAKVI were increased AST, increased ALT, anemia, hypoalbuminemia, musculoskeletal pain, increased alkaline phosphatase, leukopenia, lymphopenia, neutropenia, hypocalcemia, fatigue, vomiting, cough, constipation,...
Interactions
- 7 DRUG INTERACTIONS Strong CYP3A4 Inhibitors: Avoid coadministration of strong CYP3A4 inhibitors with VITRAKVI. If coadministration cannot be avoided, reduce the VITRAKVI dose. ( 2.5 , 7.1 ) Moderate CYP3A4 Inhibitors: Monitor for adverse reactions more frequently in patients coadministered a moderate CYP3A4 inhibitor with VITRAKVI and reduce the VITRAKVI dosage based on severity of adverse reactions. ( 7.1 ) Strong CYP3A4 Inducers: Avoid coadministration of strong CYP3A4 inducers with VITRAKVI. If coadministration cannot be avoided, increase the VITRAKVI dose. ( 2.6 , 7.