larotrectinib sulfate at a glance
Class
Selective TRK protein kinase inhibitor
Who it is for
Adults and children with eligible NTRK fusion-positive solid tumours
Tumour testing
An NTRK gene fusion must be confirmed using a validated test before treatment
Administration
Capsules or oral solution, with or without food; grapefruit must be avoided
What is larotrectinib sulfate used for?
UK-licensed use:
Treatment of adults and children with solid tumours displaying an NTRK gene fusion when disease is locally advanced, metastatic, or surgery is likely to cause severe morbidity, and no satisfactory treatment options are available.
How does larotrectinib sulfate work?
Some NTRK gene fusions produce continuously active TRK fusion proteins that signal cancer cells to grow and survive. Larotrectinib selectively blocks TRKA, TRKB and TRKC kinase activity, interrupting these signals.
larotrectinib sulfate preparations and strengths
Capsule
Route: Oral
Strengths: 25 mg, 100 mg
Oral solution
Route: Oral
Strengths: 20 mg/mL
How to take larotrectinib sulfate
Follow the specialist team's instructions and do not stop treatment without discussing it with them.
It may be taken with or without food.
Avoid grapefruit and grapefruit juice.
Swallow capsules whole with water; do not open, chew or crush them because the contents are very bitter.
Measure oral solution with the appropriate oral syringe and direct it slowly towards the inside of the cheek.
The oral solution may be given through a suitable nasogastric tube by trained carers or clinicians; do not mix it with feeding formula.
Keep the oral solution refrigerated, do not freeze it, and discard it 10 days after first opening.
larotrectinib sulfate side effects
Common or expected effects
- Nausea or vomiting
- Diarrhoea or constipation
- Tiredness or dizziness
- Anaemia or reduced white blood cell counts
- Muscle pain or weakness
- Raised liver enzymes on blood tests
- Weight gain
Get urgent medical advice
- New or worsening dizziness, altered sensation or difficulty walking
- Symptoms of liver injury, including jaundice, dark urine, upper-right abdominal pain, unusual bruising or bleeding, appetite loss, nausea or vomiting
larotrectinib sulfate in pregnancy
There are no clinical pregnancy data, and harm to an unborn baby cannot be excluded from the mechanism of action. Larotrectinib should preferably be avoided during pregnancy. Pregnancy testing and effective contraception are required around treatment; anyone pregnant or planning pregnancy should speak promptly with the specialist team.
larotrectinib sulfate while breastfeeding
It is unknown whether larotrectinib or its metabolites enter human milk, and risk to an infant cannot be excluded. Breastfeeding should stop during treatment.
larotrectinib sulfate interactions
A full medication review is needed before and during treatment, including prescribed, non-prescribed and herbal products.
Strong or moderate CYP3A, P-gp or BCRP inhibitors, including clarithromycin, itraconazole, ritonavir and voriconazole
These can increase larotrectinib exposure and the risk of adverse effects, requiring specialist review.
CYP3A or P-gp inducers, including carbamazepine, phenytoin, rifampicin and St John’s wort
These can substantially reduce larotrectinib exposure and should generally be avoided.
Narrow-therapeutic-range CYP3A substrates, including ciclosporin, fentanyl, sirolimus and tacrolimus
Larotrectinib may increase their exposure and toxicity, so closer review may be required.
Common questions about larotrectinib sulfate
Answers are fully visible for fast scanning and source review.
Is larotrectinib sulfate chemotherapy?
It is a targeted anticancer treatment rather than conventional cytotoxic chemotherapy. It selectively inhibits TRK proteins produced by certain NTRK gene fusions.
Why is tumour testing needed?
Larotrectinib is licensed only when a validated test confirms that the tumour contains an NTRK gene fusion.
Can children take larotrectinib sulfate?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.