Wiley Acta Medica Okayama 1347-9032 114 11 2023 Efficacy of gilteritinib in comparison with alectinib for the treatment of ALK-rearranged non-small cell lung cancer 4343 4354 EN Chihiro Ando Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Eiki Ichihara Department of Allergy and Respiratory Medicine, Okayama University Hospital Tatsuya Nishi Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Ayako Morita Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Naofumi Hara Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Kenji Takada Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Takamasa Nakasuka Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Hiromi Watanabe Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Hirohisa Kano Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Kazuya Nishii Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Go Makimoto Center for Clinical Oncology, Okayama University Hospital Takumi Kondo Department of Hematology and Oncology, Okayama University Hospital Kiichiro Ninomiya Department of Allergy and Respiratory Medicine, Okayama University Hospital Masanori Fujii Department of Allergy and Respiratory Medicine, Okayama University Hospital Toshio Kubo Department of Allergy and Respiratory Medicine, Okayama University Hospital Kadoaki Ohashi Department of Allergy and Respiratory Medicine, Okayama University Hospital Ken-Ichi Matsuoka Department of Hematology, Oncology and Respiratory Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Katsuyuki Hotta Center for Innovative Clinical Medicine, Okayama University Hospital Masahiro Tabata Center for Clinical Oncology, Okayama University Hospital Yoshinobu Maeda Department of Hematology, Oncology and Respiratory Medicine Katsuyuki Kiura Department of Allergy and Respiratory Medicine, Okayama University Hospital Gilteritinib is a multitarget tyrosine kinase inhibitor (TKI), approved for the treatment of FLT3-mutant acute myeloid leukemia, with a broad range of activity against several tyrosine kinases including anaplastic lymphoma kinase (ALK). This study investigated the efficacy of gilteritinib against ALK-rearranged non-small cell lung cancers (NSCLC). To this end, we assessed the effects of gilteritinib on cell proliferation, apoptosis, and acquired resistance responses in several ALK-rearranged NSCLC cell lines and mouse xenograft tumor models and compared its efficacy to alectinib, a standard ALK inhibitor. Gilteritinib was significantly more potent than alectinib, as it inhibited cell proliferation at a lower dose, with complete attenuation of growth observed in several ALK-rearranged NSCLC cell lines and no development of drug tolerance. Immunoblotting showed that gilteritinib strongly suppressed phosphorylated ALK and its downstream effectors, as well as mesenchymal-epithelial transition factor (MET) signaling. By comparison, MET signaling was enhanced in alectinib-treated cells. Furthermore, gilteritinib was found to more effectively abolish growth of ALK-rearranged NSCLC xenograft tumors, many of which completely receded. Interleukin-15 (IL-15) mRNA levels were elevated in gilteritinib-treated cells, together with a concomitant increase in the infiltration of tumors by natural killer (NK) cells, as assessed by immunohistochemistry. This suggests that IL-15 production along with NK cell infiltration may constitute components of the gilteritinib-mediated antitumor responses in ALK-rearranged NSCLCs. In conclusion, gilteritinib demonstrated significantly improved antitumor efficacy compared with alectinib against ALK-rearranged NSCLC cells, which can warrant its candidacy for use in anticancer regimens, after further examination in clinical trial settings. No potential conflict of interest relevant to this article was reported.