What is the therapeutic effect of larotinib/larlotinib?

Larotrectinib is approved for use in adult and pediatric patients with solid tumors that have neurotrophic receptor tyrosine kinase (NTRK) gene fusions but no known acquired resistance mutations that are either metastatic or for which surgical resection would result in significant morbidity and for which there are no satisfactory alternative treatments or whose cancer has progressed after treatment.

The therapeutic efficacy of larotinib/larlotinib was observed in three clinical trials evaluating the efficacy of the first 55 patients with unresectable or metastatic solid tumors containing NTRK gene fusions. The primary efficacy outcome measures were overall response rate (ORR) and duration of response, as determined by a blinded independent review committee in accordance with RECIST 1.1. The results showed an ORR of 75% (95% CI, 61%-85%), including 22% complete response and 53% partial response. At the time the database was locked, the average duration of the response had not been reached. The duration of response was 6 months or longer in 73% of patients, 9 months or longer in 63%, and 12 months or longer in 39% of patients.

In addition, larotrectinib was also conducted in three studies in 102 patients with solid tumors with NTRK gene fusions. The results showed that larotrectinib was effective in reducing the size of the patients' tumors. In these studies, 67% of patients taking larotrectinib experienced a reduction in tumor size, with tumors shrinking on average to less than half their original size. Furthermore, the tumor shrank rapidly (within 2 months).

Although larotrectinib has a good safety profile in clinical studies, it also has adverse reactions, the most common of which are fatigue, nausea, dizziness, vomiting, cough, constipation and diarrhea.