Larotrectinib efficacy and safety in adult patients with tropomyosin receptor kinase fusion sarcomas.

BACKGROUND: Larotrectinib, a first-in-class, highly selective tropomyosin receptor kinase (TRK) inhibitor, has demonstrated efficacy in adult and pediatric patients with various solid tumors harboring NTRK gene fusions. This subset analysis focuses on the efficacy and safety of larotrectinib in an expanded cohort of adult patients with TRK fusion sarcomas. METHODS: Patients (≥18 years old) with sarcomas harboring NTRK gene fusions were identified from three clinical trials. Patients received larotrectinib 100 mg orally twice daily. Response was investigator-assessed per RECIST v1.1. Data cutoff was July 20, 2021. RESULTS: At the data cutoff, 36 adult patients with TRK fusion sarcomas had initiated larotrectinib therapy: two (6%) patients had bone sarcomas, four (11%) had gastrointestinal stromal tumors, and 30 (83%) had soft tissue sarcomas. All patients were evaluable for response and demonstrated an objective response rate of 58% (95% confidence interval, 41-74). Patients responded well to larotrectinib regardless of number of prior lines of therapy. Adverse events (AEs) were mostly grade 1/2. Grade 3 treatment-emergent AEs (TEAEs) occurred in 15 (42%) patients. There were no grade 4 TEAEs. Two grade 5 TEAEs were reported, neither of which were considered related to larotrectinib. Four (11%) patients permanently discontinued treatment due to TEAEs. CONCLUSIONS: Larotrectinib demonstrated robust and durable responses, extended survival benefit, and a favorable safety profile in adult patients with TRK fusion sarcomas with longer follow-up. These results continue to demonstrate that testing for NTRK gene fusions should be incorporated into the clinical management of adult patients with various types of sarcomas. PLAIN LANGUAGE SUMMARY: Tropomyosin receptor kinase (TRK) fusion proteins result from translocations involving the NTRK gene and cause cancer in a range of tumor types. Larotrectinib is an agent that specifically targets TRK fusion proteins and is approved for the treatment of patients with TRK fusion cancer. This study looked at how well larotrectinib worked in adult patients with sarcomas caused by TRK fusion proteins. Over half of patients had a durable response to larotrectinib, with no unexpected side effects. These results show that larotrectinib is safe and effective in adult patients with TRK fusion sarcomas.

Larotrectinib Treatment for Patients With TRK Fusion-Positive Salivary Gland Cancers.

BACKGROUND: Larotrectinib is a first-in-class, highly selective, and central nervous system-active tropomyosin receptor kinase (TRK) inhibitor approved for the treatment of adult and pediatric patients with TRK fusion cancer. We report the efficacy and safety of larotrectinib in patients with TRK fusion-positive salivary gland cancers. PATIENTS AND METHODS: Patients with TRK fusion-positive salivary gland cancer treated with larotrectinib were identified from two clinical trials (NCT02122913 and NCT02576431). Patients received larotrectinib 100 mg twice daily (BID) except for one patient who received 150 mg BID in the phase I trial. The primary endpoint was objective response rate (ORR) as assessed by the investigator using Response Evaluation Criteria in Solid Tumors version 1.1. RESULTS: At the data cut-off (July 20, 2020), 24 patients with TRK fusion-positive salivary gland cancer had been treated. The most common histologies were secretory carcinoma (54%), adenocarcinoma (25%), and mucoepidermoid carcinoma (13%). All 24 patients had an ETV6-NTRK3 gene fusion. The ORR was 92% (95% confidence interval, 73-99). Best overall response was complete response in three (13%) patients, partial response in 19 (79%), and progressive disease in two (8%). The rate of progression-free survival at 24 months was 78% (median follow-up 30.9 months). Most treatment-related adverse events (AEs) were grade 1-2, and no patients discontinued treatment due to AEs. CONCLUSION: Larotrectinib demonstrated robust and durable efficacy in patients with TRK fusion-positive salivary gland tumors of various histologies, and a favorable safety profile. These findings support NTRK gene fusion testing in patients with advanced salivary gland cancers. CLINICALTRIALS.GOV NUMBERS: NCT02122913 and NCT02576431.

Efficacy and safety of larotrectinib in patients with TRK fusion-positive thyroid carcinoma.

Objective: Larotrectinib is a highly selective tropomyosin receptor kinase (TRK) inhibitor with demonstrated efficacy across various TRK fusion-positive solid tumours. We assessed the efficacy and safety of larotrectinib in patients with TRK fusion-positive thyroid carcinoma (TC). Methods: We pooled data from three phase I/II larotrectinib clinical trials (NCT02576431, NCT02122913, and NCT02637687). The primary endpoint was the investigator-assessed objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors v1.1. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), overall survival (OS), and safety. Data cut-off: July 2020. Results: Twenty-nine patients (median age: 60; range: 6-80) with TRK fusion-positive TC were treated. Tumour histology was papillary (PTC) in 20 (69%) patients, follicular (FTC) in 2 (7%), and anaplastic (ATC) in 7 (24%) patients. Among 28 evaluable patients, ORR was 71% (95% CI: 51-87); best responses were complete response in 2 (7%) patients, partial response in 18 (64%), stable disease in 4 (14%), progressive disease in 3 (11%), and undetermined in 1 (4%) due to clinical progression prior to the first post-baseline assessment. ORR was 86% (95% CI: 64-97) for PTC/FTC and 29% (95% CI 4-71) for ATC. Median time to response was 1.87 months (range 1.64-3.68). The 24-month DoR, PFS, and OS rates were 81, 69, and 76%, respectively. Treatment-related adverse events were mainly grades 1-2. Conclusion: In TRK fusion-positive TC, larotrectinib demonstrates rapid and durable disease control and a favourable safety profile in patients with advanced disease requiring systemic therapy. Significance statement: NTRK gene fusions are known oncogenic drivers and have been identified in various histologies of thyroid carcinoma, most commonly in papillary thyroid carcinoma. This is the first publication specifically studying a TRK inhibitor in a cohort of TRK fusion-positive thyroid carcinoma patients. In the current study, the highly selective TRK inhibitor larotrectinib showed durable antitumour efficacy and a favourable safety profile in patients with TRK fusion-positive thyroid carcinoma. Our findings show that patients with advanced non-medullary thyroid carcinoma who may require systemic therapy could be considered for testing for gene fusions by next-generation sequencing.

Efficacy and Safety of Larotrectinib in Patients With Tropomyosin Receptor Kinase Fusion-Positive Lung Cancers.

PURPOSE: Larotrectinib is a highly selective and CNS-active tropomyosin receptor kinase (TRK) inhibitor that has demonstrated efficacy across TRK fusion-positive cancers, regardless of the tumor type. The aim of this study was to assess the efficacy and safety of larotrectinib in patients with TRK fusion-positive lung cancers. MATERIALS AND METHODS: Data from two global, multicenter, registrational clinical trials of patients treated with larotrectinib were analyzed: a phase II adult and young adult basket trial (NCT02576431) and a phase I adult trial (NCT02122913). The primary end point was objective response rate (ORR). RESULTS: By July 20, 2020, 20 patients with TRK fusion-positive lung cancer had been treated. The ORR by investigator assessment among 15 evaluable patients was 73% (95% CI, 45 to 92); one (7%) patient had a complete response, 10 (67%) had a partial response, three (20%) had stable disease, and one (7%) had progressive disease as best response. The median duration of response, progression-free survival, and overall survival were 33.9 months (95% CI, 5.6 to 33.9), 35.4 months (95% CI, 5.3 to 35.4), and 40.7 months (95% CI, 17.2 to not estimable), respectively. Among patients with baseline CNS metastases, the ORR was 63% (95% CI, 25 to 91). Adverse events were mainly grade 1 or 2. CONCLUSION: Larotrectinib is highly active with rapid and durable responses, extended survival benefit, and a favorable long-term safety profile in patients with advanced lung cancer harboring NTRK gene fusions, including those with CNS metastases. These findings support routine testing for NTRK fusions in patients with lung cancer.

Diagnostic testing approaches for the identification of patients with TRK fusion cancer prior to enrollment in clinical trials investigating larotrectinib.

INTRODUCTION: NTRK gene fusions are targetable oncogenic drivers independent of tumor type. Prevalence varies from highly recurrent in certain rare tumors to <1% in common cancers. The selective TRK inhibitor larotrectinib was shown to be highly active in adult and pediatric patients with tumors harboring NTRK gene fusions. METHODS: We examined the techniques used by local sites to detect tumor NTRK gene fusions in patients enrolled in clinical trials of larotrectinib. We also report the characteristics of the detected fusions in different tumor types. RESULTS: The analysis included 225 patients with 19 different tumor types. Testing methods used were next-generation sequencing (NGS) in 196 of 225 tumors (87%); this was RNA-based in 96 (43%); DNA-based in 53 (24%); DNA/RNA-based in 46 (20%) and unknown in 1 (<1%); FISH in 14 (6%) and PCR-based in 12 (5%). NanoString, Sanger sequencing and chromosome microarray were each utilized once (<1%). Fifty-four different fusion partners were identified, 39 (72%) of which were unique occurrences. CONCLUSIONS: The most common local testing approach was RNA-based NGS. Many different NTRK gene fusions were identified with most occurring at low frequency. This supports the need for validated and appropriate testing methodologies that work agnostic of fusion partners.

Efficacy and safety of larotrectinib in TRK fusion-positive primary central nervous system tumors.

BACKGROUND: Larotrectinib is a first-in-class, highly selective tropomyosin receptor kinase (TRK) inhibitor approved to treat adult and pediatric patients with TRK fusion-positive cancer. The aim of this study was to evaluate the efficacy and safety of larotrectinib in patients with TRK fusion-positive primary central nervous system (CNS) tumors. METHODS: Patients with TRK fusion-positive primary CNS tumors from two clinical trials (NCT02637687, NCT02576431) were identified. The primary endpoint was investigator-assessed objective response rate (ORR). RESULTS: As of July 2020, 33 patients with TRK fusion-positive CNS tumors were identified (median age: 8.9 years; range: 1.3-79.0). The most common histologies were high-grade glioma (HGG; n = 19) and low-grade glioma (LGG; n = 8). ORR was 30% (95% confidence interval [CI]: 16-49) for all patients. The 24-week disease control rate was 73% (95% CI: 54-87). Twenty-three of 28 patients (82%) with measurable disease had tumor shrinkage. The 12-month rates for duration of response, progression-free survival, and overall survival were 75% (95% CI: 45-100), 56% (95% CI: 38-74), and 85% (95% CI: 71-99), respectively. Median time to response was 1.9 months (range 1.0-3.8 months). Duration of treatment ranged from 1.2-31.3+ months. Treatment-related adverse events were reported for 20 patients, with grade 3-4 in 3 patients. No new safety signals were identified. CONCLUSIONS: In patients with TRK fusion-positive CNS tumors, larotrectinib demonstrated rapid and durable responses, high disease control rate, and a favorable safety profile.