NTRK Gene Fusion–Positive Solid Tumors
Entrectinib
Indication. Entrectinib is indicated for adult and pediatric patients with solid tumors and an NTRK gene fusion without a known acquired resistance variant; with disease that is metastatic or where surgical resection is likely to result in severe morbidity; and who have disease progression after treatment or have no satisfactory standard therapy.
Evidence. Five multicenter single-arm clinical trials evaluated the efficacy of entrectinib in patients with NTRK-positive tumors. Three of these trials evaluated a total of 54 adult patients who received entrectinib at various doses and schedules. Two of these trials evaluated a total of 33 pediatric patients.[1,2][Level of evidence C3]
- ALKA-372-001; adult patients.
- STARTRK-1 (NCT02097810); adult patients.
- STARTRK-2 (NCT02568267); adult patients.
- STARTRK-NG (NCT02650401); pediatric patients.
- TAPISTRY (NCT04589845); pediatric patients.
Efficacy. Among the 54 adult patients, the overall response rate, as determined by independent review, was 57% (95% confidence interval [CI], 43%–71%). The median follow-up was 15 months.[1] Among the 33 pediatric patients, the objective response rate was 70% (95% CI, 51%–84%), and the median duration of response was 25.4 months (95% CI, 14.3–not evaluable). The median follow-up was not defined.[2]
Identification of biomarker. Identification of positive NTRK gene fusion status was determined at local laboratories or a central laboratory using nucleic acid-based tests prior to enrollment. Not all NTRK variants are gene fusions. Entrectinib has not shown clinical efficacy in patients with nonfusion NTRK variants..
Larotrectinib
Indication. Larotrectinib is indicated for adult and pediatric patients with solid tumors and an NTRK gene fusion without a known acquired resistance variant; with disease that is metastatic or where surgical resection is likely to result in severe morbidity; and who have disease progression after treatment and have no satisfactory alternative treatment options.
Evidence. U.S. Food and Drug Administration (FDA) approval was based on data from three multicenter, open-label, single-arm clinical trials: LOXO-TRK-14001 (NCT02122913), SCOUT (NCT02637687), and NAVIGATE (NCT02576431).[3,4][Level of evidence C3]
Efficacy. Among 55 patients with unresectable or metastatic solid tumors harboring an NTRK gene fusion enrolled across the three trials, the overall response rate was 75% (95% CI, 61%–85%). The complete response rate was 22%, and the partial response rate was 53%. The median follow-up was 8.3 months.[3,5]
Identification of biomarker. NTRK gene fusion status was prospectively determined at local laboratories using next-generation sequencing (NGS) or fluorescence in situ hybridization (FISH). Not all NTRK variants are gene fusions. Entrectinib has not shown clinical efficacy in patients with nonfusion NTRK variants..
Repotrectinib
Indication. Repotrectinib is indicated for adult and pediatric patients with an NTRK gene fusion and solid tumors that are locally advanced or metastatic for which surgical resection may cause severe morbidity.
Evidence. FDA approval was based on data from TRIDENT-1 (NCT03093116), a multicenter, single-arm, open-label, multicohort trial.[6,7,8][Level of evidence C3]
Efficacy. In 88 adult patients with locally advanced or metastatic NTRK gene fusion–positive solid tumors, the overall response rate was 58% (95% CI, 41%–73%) for patients who had not received prior NTRK tyrosine kinase inhibitors (TKIs) (n = 40) and 50% (95% CI, 35%–65%) for patients who had previously received NTRK TKIs (n = 48). The median duration of response was not estimable in the TKI-naïve group and was 9.9 months (95% CI, 7.4–13.0) in the TKI-pretreated group. The median follow-up was 24.0 months.[6,8]
Identification of biomarker. NTRK gene fusion status was prospectively determined at local laboratories using NGS, Sanger sequencing, reverse transcription–polymerase chain reaction, or FISH. Not all NTRK variants are gene fusions. Repotrectinib has not shown clinical efficacy in patients with nonfusion NTRK variants.
References:
- Drilon A, Siena S, Ou SI, et al.: Safety and Antitumor Activity of the Multitargeted Pan-TRK, ROS1, and ALK Inhibitor Entrectinib: Combined Results from Two Phase I Trials (ALKA-372-001 and STARTRK-1). Cancer Discov 7 (4): 400-409, 2017.
- Desai AV, Robinson GW, Gauvain K, et al.: Entrectinib in children and young adults with solid or primary CNS tumors harboring NTRK, ROS1, or ALK aberrations (STARTRK-NG). Neuro Oncol 24 (10): 1776-1789, 2022.
- Drilon A, Laetsch TW, Kummar S, et al.: Efficacy of Larotrectinib in TRK Fusion-Positive Cancers in Adults and Children. N Engl J Med 378 (8): 731-739, 2018.
- Laetsch TW, DuBois SG, Mascarenhas L, et al.: Larotrectinib for paediatric solid tumours harbouring NTRK gene fusions: phase 1 results from a multicentre, open-label, phase 1/2 study. Lancet Oncol 19 (5): 705-714, 2018.
- U.S. Food and Drug Administration: FDA approves larotrectinib for solid tumors with NTRK gene fusions. U.S. Food and Drug Administration, 2018. Available online. Last accessed January 30, 2025.
- Drilon A, Camidge DR, Lin JJ, et al.: Repotrectinib in ROS1 Fusion-Positive Non-Small-Cell Lung Cancer. N Engl J Med 390 (2): 118-131, 2024.
- Solomon BJ, Drilon A, Lin JJ, et al.: Repotrectinib in patients (pts) with NTRK fusion-positive (NTRK+) advanced solid tumors, including NSCLC: Update from the phase I/II TRIDENT-1 trial. [Abstract] Ann Oncol 34 (Suppl 2): A-787-788, 2023.
- U.S. Food and Drug Administration: FDA grants accelerated approval to repotrectinib for adult and pediatric patients with NTRK gene fusion-positive solid tumors. U.S. Food and Drug Administration, 2024. Available online. Last accessed January 23, 2025.