TRK tyrosine-kinase inhibitor

Larotrectinib (Specialist drug)

Brand names: Vitrakvi

Larotrectinib is an oral selective tropomyosin receptor kinase (TRK) inhibitor used as a tumour-agnostic, specialist treatment for cancers harbouring an NTRK gene fusion. It is taken under oncology supervision.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It selectively inhibits the TRKA, TRKB and TRKC kinases encoded by the NTRK genes, blocking the constitutive signalling driven by NTRK gene fusions.

Prescribing in practice

Use only after a confirmed NTRK gene fusion, as efficacy depends on this molecular target.
Neurological effects such as dizziness and disturbances of gait, and hepatotoxicity, can occur and may require dose adjustment.
It is a CYP3A4 substrate, so avoid strong inducers and inhibitors where possible.

Monitoring

Monitor liver function tests and for neurological effects during treatment.

Counselling the patient

Report dizziness, unsteadiness or confusion, and take care with driving or tasks needing concentration.
Avoid grapefruit and tell the team about all other medicines.
Effective contraception is required during and after treatment as advised.

Evidence & guidelines

Larotrectinib produced high, durable response rates across NTRK fusion-positive tumours in pooled basket trials.

Reference: NICE TA630; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways