Sequential ALK Inhibitors Can Select for Lorlatinib-Resistant Compound ALK Mutations in ALK-Positive Lung Cancer

Cancer Discov. 2018 Jun;8(6):714-729. doi: 10.1158/2159-8290.CD-17-1256. Epub 2018 Apr 12.

Abstract

The cornerstone of treatment for advanced ALK-positive lung cancer is sequential therapy with increasingly potent and selective ALK inhibitors. The third-generation ALK inhibitor lorlatinib has demonstrated clinical activity in patients who failed previous ALK inhibitors. To define the spectrum of ALK mutations that confer lorlatinib resistance, we performed accelerated mutagenesis screening of Ba/F3 cells expressing EML4-ALK. Under comparable conditions, N-ethyl-N-nitrosourea (ENU) mutagenesis generated numerous crizotinib-resistant but no lorlatinib-resistant clones harboring single ALK mutations. In similar screens with EML4-ALK containing single ALK resistance mutations, numerous lorlatinib-resistant clones emerged harboring compound ALK mutations. To determine the clinical relevance of these mutations, we analyzed repeat biopsies from lorlatinib-resistant patients. Seven of 20 samples (35%) harbored compound ALK mutations, including two identified in the ENU screen. Whole-exome sequencing in three cases confirmed the stepwise accumulation of ALK mutations during sequential treatment. These results suggest that sequential ALK inhibitors can foster the emergence of compound ALK mutations, identification of which is critical to informing drug design and developing effective therapeutic strategies.Significance: Treatment with sequential first-, second-, and third-generation ALK inhibitors can select for compound ALK mutations that confer high-level resistance to ALK-targeted therapies. A more efficacious long-term strategy may be up-front treatment with a third-generation ALK inhibitor to prevent the emergence of on-target resistance. Cancer Discov; 8(6); 714-29. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 663.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaplastic Lymphoma Kinase / genetics*
  • Animals
  • Cell Line, Tumor
  • Crizotinib / administration & dosage
  • Crizotinib / pharmacology
  • Drug Resistance, Neoplasm*
  • Ethylnitrosourea / adverse effects
  • Female
  • Humans
  • Lactams, Macrocyclic / administration & dosage*
  • Lactams, Macrocyclic / pharmacology
  • Lung Neoplasms / chemically induced
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / genetics*
  • Mice
  • Mutation*
  • Oncogene Proteins, Fusion / genetics
  • Protein Kinase Inhibitors / administration & dosage
  • Protein Kinase Inhibitors / pharmacology
  • Whole Exome Sequencing
  • Xenograft Model Antitumor Assays

Substances

  • EML4-ALK fusion protein, human
  • Lactams, Macrocyclic
  • Oncogene Proteins, Fusion
  • Protein Kinase Inhibitors
  • Crizotinib
  • ALK protein, human
  • Anaplastic Lymphoma Kinase
  • lorlatinib
  • Ethylnitrosourea