Hazem El-Osta, Rodney Shackelford

The fusion of echinoderm microtubule-associated protein-like 4 with the anaplastic lymphoma kinase (EML4-ALK) is found in 3%-7% of non-small-cell lung cancer (NSCLC) cases and confers sensitivity to crizotinib, the first United States Food and Drug Administration (FDA)-approved ALK inhibitor drug. Although crizotinib has an excellent initial therapeutic effect, acquired resistance to this drug invariably develops within the first year of treatment. Resistance may involve secondary gatekeeper mutations within the ALK gene interfering with crizotinib-ALK interactions, or compensatory activation of aberrant bypass signaling pathways. New therapeutic strategies to overcome crizotinib resistance are needed. Ceritinib, a second-generation ALK inhibitor, overcomes several crizotinib-resistant ALK mutations and has demonstrated efficacy against tumor growth in several in vitro and in vivo preclinical models of crizotinib resistance. Notably, the dose-escalation Phase I ASCEND-1 trial has shown a marked activity of ceritinib in both crizotinib-naïve and crizotinib-resistant ALK-rearranged lung cancer. The overall response rate was 58% in a subgroup of patients with ALK-rearranged late-stage NSCLC. Drug discontinuation rate due to toxicity was 10%. The standard dose was established at 750 mg daily. This paper outlines the pathogenesis and treatment of ALK-positive lung cancer, focuses on the preclinical and clinical results surrounding the accelerated FDA approval of ceritinib for the treatment of ALK-positive metastatic NSCLC patients who have progressed on/or are crizotinib intolerant, and discusses the potential efforts seeking to maximize ceritinib efficacy and expand its usage to other indications in cancer therapy.