cancers Review Tumor Resistance against ALK Targeted Therapy-Where It Comes From and Where It Goes Geeta Geeta Sharma 1,† ID , Ines Mota 2,†, Luca Mologni 1,3 ID , Enrico Patrucco 2, Carlo Gambacorti-Passerini 1,3,4,† and Roberto Chiarle 2,5,†,* 1 Department of Medicine and Surgery, University of Milano-Bicocca, Monza 20900, Italy;
[email protected] (G.G.S.);
[email protected] (L.M.);
[email protected] (C.G.-P.) 2 Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin 10124, Italy;
[email protected] (I.M.);
[email protected] (E.P.) 3 Galkem Srl, Monza 20900, Italy 4 Hematology and Clinical Research Unit, San Gerardo Hospital, Monza 20900, Italy 5 Department of Pathology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA * Correspondence:
[email protected] † These authors contributed equally to this work. Received: 1 February 2018; Accepted: 26 February 2018; Published: 28 February 2018 Abstract: Anaplastic lymphoma kinase (ALK) is a validated molecular target in several ALK-rearranged malignancies, particularly in non-small-cell lung cancer (NSCLC), which has generated considerable interest and effort in developing ALK tyrosine kinase inhibitors (TKI). Crizotinib was the first ALK inhibitor to receive FDA approval for ALK-positive NSCLC patients treatment. However, the clinical benefit observed in targeting ALK in NSCLC is almost universally limited by the emergence of drug resistance with a median of occurrence of approximately 10 months after the initiation of therapy. Thus, to overcome crizotinib resistance, second/third-generation ALK inhibitors have been developed and received, or are close to receiving, FDA approval.