Case Report Successful Crizotinib Rechallenge After Crizotinib-induced Interstitial Lung

We report the case of a 70-year-old Japanese male diagnosed with advanced lung adenocar-cinoma harboring the echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion gene. As soon as crizotinib was administered, tumor shrank immediately. On Day 25, he developed interstitial lung disease. Bronchoalveolar lavage fluid analysis demonstrated elevated lymphocytes fractionation. A drug lymphocyte stimulating test for crizotinib with the bronchoalveolar lavage lymphocytes was negative. Crizotinib administration was discontinued, but a life-threatening flare of tumor growth occurred. Since there was no alternative treatment for the lung cancer, we restarted crizotinib in combination with prednisolone. The patient experi-enced neither disease progression nor recurrence of interstitial lung disease at 6 months. In cases in which no alternate treatment is known, crizotinib retreatment combined with steroid therapy after crizotinib-induced interstitial lung disease could be considered after a careful con-sideration of the potential risks and benefits. Key words: EML4-ALK – crizotinib – interstitial lung disease – drug lymphocyte stimulating test (DLST) – bronchoalveolar lavage (BAL