Are the adverse effects of larotrectinib serious?

The tropomyosin receptor kinase (TRK) fusion protein produced by the fusion of the neurotrophic tyrosine receptor kinase (NTRK) gene is a major oncogenic driver that is rare in a variety of tumors. Vitrakvi larotrectinib is a highly selective central nervous system active TRK inhibitor approved by the U.S. Food and Drug Administration (FDA), the European Medicines Agency (EMA), and more than 40 countries for the treatment of TRK fusion solid tumors in adult and pediatric patients.

One study included adult and pediatric patients with locally advanced or metastatic TRK-fusion cancer treated with Vitrakvi larotrectinib, and adult patients were grouped by tumor type and followed for at least 2 years. Regardless of tumor type, patients aged < 18 years will be enrolled in a "pediatric" cohort and followed up for 5 years to assess the risk of potential long-term adverse effects of Vitrakvi larotrectinib on its growth and development.

Surgery should be avoided in patients with infantile fibrosarcoma (e.g., the number of patients who are able to undergo therapeutic surgery (excluding amputation) as a result of larotrectinib will be described. Larotrectinib treatment patterns in real-world practice, including dose and duration of treatment, will be described.

VITRAKVI may cause serious side effects, including:

Central nervous system (CNS) toxicity. VITRAKVI may cause confusion, dizziness, concentration and memory problems, difficulty concentrating, mood changes, and sleep problems.

Fracture. FRACTURES CAN OCCUR IN VITRAKVI. If you experience pain, changes in mobility, or bone abnormalities, seek immediate medical attention.

Hepatotoxicity. It is common for people taking VITRAKVI to have elevated liver enzymes in blood tests. Increased liver enzymes can sometimes lead to liver problems and can become severe. During the first month of VITRAKVI treatment, blood tests are done every two weeks to check liver function, and then monthly as needed. If symptoms of liver toxicity are experienced, including: nausea or vomiting or pain in the upper right side of the stomach, loss of appetite, seek immediate medical attention.

The most common side effects of VITRAKVI include: muscle and bone pain, low red blood cell and white blood cell counts, low levels of a protein called albumin in the blood, tiredness, coughing, elevated levels of alkaline phosphatase in the blood (to check for liver or bone problems), diarrhea, constipation, low calcium levels in the blood, dizziness, vomiting, nausea, fever, abdominal pain.

VITRAKVI may affect a woman's fertility and may affect the ability to get pregnant.