Suboptimal clinician awareness of appropriate NTRK fusion testing and TRK inhibitor use in solid tumors

229 Background: Since late 2018, 2 TRK inhibitors—larotrectinib and entrectinib—have been approved by the EMA and FDA for treating patients with advanced solid tumors harboring an NTRK fusion and progressive disease or no therapeutic alternatives. It is recommended that testing for NTRK fusions occur as early as possible after a diagnosis of advanced disease in patients with solid tumors to inform potential use of TRK inhibitors. Methods: Between April 2018 and April 2021, we conducted multiple live and online educational activities for oncology healthcare professionals (HCPs) on NTRK fusion testing and/or TRK inhibitor treatment for varied solid tumors. Each activity included polling questions designed to assess HCP knowledge and practice patterns. In this analysis, we assessed HCP responses to these questions to evaluate awareness of expert recommendations on NTRK fusion testing and the selection of TRK inhibitor therapy for appropriate patients. Results: In 6 live and online activities with data from April 2018 to April 2021, 29% of HCPs (n = 844) indicated that they ordered molecular profiling to test for NTRK fusions in all solid tumors in their current practice. Of note, low rates of testing were reported in TRK inhibitor/ NTRK testing-focused activities throughout this time period, with no significant increase over time. In assessing different patient cases across 8 activities where experts recommended TRK inhibitor therapy as optimal, many HCPs did not select a TRK inhibitor, with considerable variance by tumor type (Table). *For all cases, experts selected larotrectinib and/or entrectinib as optimal treatment. †HCP respondents. GBM, glioblastoma; GI, gastrointestinal; MSI-H, microsatellite instability-high; PD, progressive disease; PTC, papillary thyroid cancer.Conclusions: The rate of broad testing for NTRK fusions across patients with solid tumors remains low, and many HCPs lack awareness of when to consider a TRK inhibitor. Educational activities designed to address these deficiencies would be of clear benefit to HCPs treating patients with advanced solid tumors. A detailed analysis of HCP trends will be presented.[Table: see text]