Indications
Larotrectinib is a targeted cancer medicine for adults and children with solid tumours that have a specific gene change called an NTRK gene fusion. It is used when the cancer has spread or cannot be removed safely by surgery, and when there are no other satisfactory treatments. A laboratory test on the tumour is needed first to confirm the NTRK fusion.
How It Works
In some cancers, an NTRK gene fuses with another gene and produces abnormal TRK proteins that are always switched on, driving the cancer cells to grow. Larotrectinib is a TRK inhibitor: it blocks these abnormal proteins, which can slow or stop tumour growth and shrink the tumour, whatever part of the body the cancer started in.
Dosage and Administration
Larotrectinib is taken by mouth as capsules or an oral solution, usually twice a day, exactly as prescribed by your cancer specialist. The dose for children is based on body size. It can be taken with or without food. Swallow capsules whole with water. Do not change or stop the dose without your doctor’s advice. Regular blood tests are needed.
Interactions
Strong enzyme blockers such as Ketoconazole, Itraconazole, Clarithromycin and Ritonavir, and grapefruit juice, can raise Larotrectinib levels; strong inducers such as Rifampicin, Carbamazepine, Phenytoin and St John’s Wort can lower them. It may affect some medicines broken down by the same liver enzymes, such as Midazolam. Tell your doctor about all medicines and herbal products.
Contraindications
- Allergy to Larotrectinib or any ingredient.
Side Effects
Common effects include tiredness, dizziness, nausea, vomiting, constipation or diarrhoea, muscle pain, cough, weight gain, raised liver enzymes and low blood counts (anaemia or low white cells).
Get urgent medical help if you have confusion, problems with balance or walking, mood changes, severe sleepiness, fainting, yellowing of the skin or eyes, dark urine, fever with chills, or unusual bleeding or bruising.
Pregnancy and Lactation
Larotrectinib may harm an unborn baby. Women who could become pregnant and men with a female partner should use effective contraception during treatment and for at least one month after the last dose. Hormonal contraceptive users should also use a barrier method. Do not breastfeed during treatment and for 3 days after the last dose.
Precautions and Warnings
Liver blood tests are checked every 2 weeks in the first month, then monthly. Nervous system effects such as dizziness and confusion can occur, so do not drive or use machines if affected. Tell your doctor about liver problems. Larotrectinib may reduce fertility in men and women.
Overdose
Experience is limited. Contact a doctor or hospital immediately; treatment is supportive.
Therapeutic Class
Antineoplastic (anticancer) agent; tropomyosin receptor kinase (TRK) inhibitor.
Storage
Store capsules below 30°C in a dry place, away from light and out of the reach of children. Store the oral solution as directed on the pack, usually in a refrigerator at 2 to 8°C, do not freeze.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.