Yılmaz F, Yaşar S, Mandel NM, Kaçan T, Özdemir M, Doğu GG, Şengül N, Meydan N, Başal FB, Tolunay PK, Hamamcı MB, Dinçer OS, Bahçeci A, Özer L, Ajredini M, Kırca Ö, Yersal Ö, Can O, Günaldı M, Demir G, and Yalçın Ş
Background: Neurotrophic tyrosine receptor kinase (NTRK) gene fusions represent rare somatic mutations in many types of cancer and have enabled the use of promising targeted therapies. In clinical studies, increased response rates to tropomyosin receptor kinase inhibitors have been demonstrated in NTRK fusion-positive cancer types; however, real-world experiences on these targeted agents are scarce., Objective: We evaluated the clinical characteristics and treatment responses of NTRK fusion-positive patients who received entrectinib treatment within the scope of an early access program in Turkey., Patients and Methods: This multicenter, retrospective analysis involved 17 patients with solid tumors harboring NTRK fusions or rearrangements from 14 oncology centers between June 2019 and 31 March 2024. Demographic and clinical data were obtained via retrospective review of medical records with a cutoff date of 31 March 2024., Results: The median age at diagnosis of the patients in our study was 42 [interquartile range (IQR) 33-60] years. Nine different types of solid tumors were diagnosed in these patients. The most common NTRK gene rearrangements involved NTRK1 (n = 8), followed by NTRK3 (n = 7). The median duration of entrectinib usage was 6.9 (IQR 3.1-16.1) months. Dose reductions due to side effects were performed in four patients: two due to leukopenia, one due to visual disturbance, and one due to troponin elevation. Leukopenia was the most commonly observed side effect. The objective response rate (ORR) was 35.3% (95% confidence interval (CI) 14.2-62.7), with complete response (CR) achieved in four patients. The duration of response (DOR) in patients who responded after initiating entrectinib was 9.8 (95% CI 0-30.7) months, the median overall survival (mOS) in all patients was 20.8 (95% CI 0-48.5) months, and the time-to-treatment failure (TTF) was 6.4 (95% CI 0-13.5) months., Conclusions: In this retrospective study, we aimed to obtain real-world data concerning the use of entrectinib in patients with solid tumors harboring NTRK fusion genes. Although our findings are partially similar to the results of clinical studies, prospective studies in larger patient groups with more diverse tumor types and different demographic characteristics are needed to confirm the findings., Competing Interests: Declarations Funding The authors received no financial support for the research, authorship, and/or publication of this article. Conflict of interest statement Feride Yılmaz, Serkan Yaşar, Nil Molinas Mandel, Turgut Kaçan, Melek Özdemir, Gamze Gököz Doğu, Nilay Şengül, Nezih Meydan, Fatma Buğdaycı Başal, Pınar Kubilay Tolunay, Melda Berber Hamamcı, Oğuz Salih Dinçer, Aykut Bahçeci, Leyla Özer, Miraç Ajredini, Önder Kırca, Özlem Yersal, Orçun Can, Meral Günaldı, Gökhan Demir, and Şuayib Yalçın declare that they have no conflicts of interest that might be relevant to the contents of this article. Ethics declarations The study was conducted in accordance with the Declaration of Helsinki and its amendments and with Good Clinical Practice guidelines. Ethical approval (approval date and number 2 April 2024, 23/536) for this study was obtained from the Hacettepe University Health Sciences Research Ethics Board, Turkey. Consent to participate The need for consent for this study was waived by the institutional review board (Hacettepe University Health Sciences Research Ethics Board) because of its retrospective design. Consent to publish Not applicable. Availability of data and materials Since the participants in this retrospective study, which was conducted with the permission of the Hacettepe Health Sciences Ethics Committee, did not give written consent for their data to be disclosed to the public, supporting data are not available owing to the sensitive nature of the research. Code availability Not applicable. Author contributions Feride Yilmaz: conceptualization; data curation; formal analysis; investigation; methodology; validation; visualization; writing—original draft. Nil Molinas Mandel, Turgut Kaçan, Melek Özdemir, Gamze Gököz Doğu, Oğuz Salih Dinçer, Leyla Özer, Miraç Ajredini, Önder Kırca, Özlem Yersal: conceptualization; data curation; investigation; methodology; validation; visualization. Serkan Yaşar and Şuayib Yalçın: conceptualization; data curation; methodology; writing, review and editing. Nilay Şengül Samancı, Nezih Meydan, Fatma Buğdaycı Başal, Pınar Kubilay Tolunay, Melda Berber Hamamcı: conceptualization; data curation; methodology; supervision; writing, review and editing. Aykut Bahçeci, Orçun Can, Meral Günaldı, Gökhan Demir: conceptualization; methodology; supervision; validation; review and editing. Şuayib Yalçın: conceptualization; data curation; methodology; supervision; validation; review and editing., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)