Weitaikai Larotrectinib Sulfate Oral Solution

1. Indications and Usage
Solid Tumors: Indicated for adult and pediatric patients with solid tumors that have an NTRK gene fusion without known acquired resistant mutations, who are metastatic or locally advanced and have no satisfactory alternative treatments or have progressed following treatment.
2. Dosage and Administration
Standard Dosage: The recommended dosage for patients with a body surface area (BSA) of at least 1.0 m² is 100 mg taken orally twice daily. For pediatric patients with a BSA less than 1.0 m², the recommended dosage is 100 mg/m² taken orally twice daily, with a maximum of 100 mg per dose.
Administration: Can be taken with or without food. The oral solution should be administered using an oral syringe. Do not mix with other liquids.
Storage and Handling: The oral solution must be stored in a refrigerator at 2°C to 8°C. Once the bottle has been opened, any unused portion must be discarded 90 days later.
3. Mechanism of Action
TRK Inhibition: Larotrectinib is a potent and selective inhibitor of tropomyosin receptor kinases (TRK) A, B, and C.
Pathway Blocking: By inhibiting TRK fusion proteins, it blocks the signaling pathways responsible for tumor cell proliferation and survival, thereby exerting a potent anti-tumor effect across various tumor types.
4. Safety and Warnings
Embryo-fetal Toxicity: Can cause fetal harm. Effective contraception is required during treatment and for at least one month after the final dose in females and males with partners of reproductive potential.
Hepatotoxicity: Monitor liver function tests (ALT, AST, and bilirubin) at baseline and regularly during treatment; dose modification or discontinuation may be necessary for severe elevations.
Neurologic Toxicity: Monitor for symptoms such as dizziness, gait disturbance, and paresthesia, which are common adverse reactions.
5. Adverse Reactions and Clinical Research
Common Adverse Reactions: Most frequently reported reactions (incidence ≥20%) include fatigue, nausea, vomiting, increased ALT, increased AST, constipation, diarrhea, and cough.
Clinical Research Results: Clinical trials demonstrate high objective response rates and durable responses in patients with NTRK fusion-positive solid tumors, regardless of the tumor origin.
6. Drug Interactions
CYP3A4 Interactions: Larotrectinib is metabolized by CYP3A4. Concomitant use with strong or moderate CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin) significantly increases exposure, necessitating dosage reduction. Conversely, strong CYP3A4 inducers decrease exposure and should be avoided.
P-gp Interactions: Concomitant use with P-glycoprotein (P-gp) inhibitors or inducers may affect the absorption and exposure of larotrectinib.
7. Pharmaceutical Information
Active Ingredient: Larotrectinib (as sulfate).
Dosage Forms: Oral solution (20 mg/mL concentration).
Storage: Store at 2°C to 8°C in a non-clear bottle to protect from light.