For the First Time, a Drug Is Effective Across Different Cancers and in Children and Adults: Larotrectinib

We are living through years of firsts in cancer treatment. Witnessing this excites us and strengthens our belief that cancer will become a completely treatable disease. One such first is the new chemotherapy drug Larotrectinib, shown to be effective both in children and adults and across different cancers sharing a particular genetic characteristic.

Larotrectinib’s efficacy was demonstrated in a study of 17 different cancers involving 50 patients, at the American Cancer Congress ASCO 2017. In 38 patients, or of every 4 patients, 3 had tumors that responded to the new treatment and shrank. At treatment month 12, this positive response was still continuing in %79 of responding patients.

Larotrectinib is an oral tablet drug that selectively inhibits tropomyosin receptor kinase (TRK) fusion proteins

In some cancer cells, the TRK gene combines with other genes; this occurs in % 0.5 - % 1 of all cancers, but in some rare cancers it exceeds % 90. Examples include salivary gland cancer, juvenile (childhood or young-age) breast cancer and infantile fibrosarcoma. TRK positivity can also occur in colon (large bowel), lung, pancreatic and thyroid cancers, and melanoma skin cancer.

The most common side effects were fatigue and mild dizziness. Mild dizziness is considered normal with this treatment because normal TRK protein helps control balance. No patient had to discontinue because of side effects. This development is among the most important steps in precision medicine / personalized treatments , because regardless of the tumor’s organ of origin or the patient’s age, a genetic change caused by a mutation was targeted, producing important treatment responses.

If Larotrectinib, developed against this genetic mutation, succeeds in more comprehensive studies, genetic tests assessing TRK fusion in advanced cancer patients may become part of our routine practice. .

Further Reading: About TRK Fusions

TRK fusions were first discovered in colon cancer in 1982, but only the development of technologies such as next-generation DNA sequencing in recent years made it possible to detect this abnormality in cancer patients. Scientists have now identified more than 50 different genes that combine with TRK genes. Abnormal TRK fusion proteins are constantly “on,” sending cancer cells signals to grow and multiply.