FDA Approves Larotrectinib in Solid Tumors With NTRK Gene Fusion
Posted: Thursday, November 29, 2018
On November 26, 2018, the U.S. Food and Drug Administration granted accelerated approval to larotrectinib (Vitrakvi) in the treatment of adult and pediatric patients with solid tumors with a neurotrophic receptor tyrosine kinase (NTRK) gene fusion without a known acquired resistance mutation, who have metastatic disease or for whom surgical resection is likely to result in severe morbidity, and who have no satisfactory alternative treatments or have experienced disease progression following treatment.
In clinical trials, larotrectinib demonstrated a 75% overall response rate across different types of solid tumors. These responses appeared to be durable, with 73% of responses lasting at least 6 months and 39% lasting 12 months or more at the time the results were analyzed. Examples of tumor types with an NTRK fusion that responded to larotrectinib include soft-tissue sarcoma, salivary gland cancer, infantile fibrosarcoma, thyroid cancer, and lung cancer.
The safety of larotrectinib was evaluated in 176 patients enrolled across 3 clinical trials, including 44 pediatric patients. The most common adverse reactions (≥ 20%) with larotrectinib were fatigue, nausea, dizziness, vomiting, increased aspartate transaminase levels, cough, increased alanine transaminase levels, constipation, and diarrhea.
This is the second time the FDA has approved a cancer treatment based on a common biomarker across different types of tumors rather than the location in the body where the tumor originated. In May 2017, pembrolizumab (Keytruda) was granted accelerated approval for treatment of adult and pediatric patients with unresectable or metastatic microsatellite instability–high or mismatch repair–deficient solid tumors progressing after prior treatment; the FDA called this approval the “first tissue/site-agnostic approval.”