Crizotinib primary resistance overcome by ceritinib in a patient with ALK-rearranged non-small cell lung cancer.

We report on the case of a patient affected by advanced non-small cell lung cancer (NSCLC) harboring an anaplastic lymphoma kinase (ALK) gene rearrangement who did not respond to crizotinib but subsequently benefited from treatment with ceritinib (LDK378). Although second-generation ALK inhibitors have shown activity in patients pretreated with crizotinib who experienced secondary resistance, this is the first report to date describing their efficacy in a case of primary resistance. Of note, none of the previously described molecular mechanisms explaining resistance to crizotinib was detected on either the initial or post-crizotinib biopsies. We hypothesize that crizotinib was powerless in controlling disease progression due to its inadequate inhibition of ALK signaling. Although we lack any molecular evidence elucidating the primary crizotinib resistance, we believe that ceritinib treatment led to tumor regression thanks to its superior biological potency.