A 52-year-old man was diagnosed with primary lung adenocarcinoma with multiple brain, bone, and lung metastases (clinical stage IVB, T4N3M1c). A mild reduction in primary tumor size was observed following whole-brain radiotherapy against brain metastases and systemic chemotherapy with cisplatin and pemetrexed. Following a systemic seizure, he lost consciousness and his performance status (PS) deteriorated from 1 to 4. Given a positive anaplastic lymphoma kinase (ALK) fusion gene and his dysphagia, alectinib was administered via a nasogastric tube using a simple suspension method. The size of the primary tumor and brain metastases reduced markedly. His dysphagia improved with an improvement in his consciousness level. His PS improved from 4 to 1. Progression-free survival duration was 38 months with a preserved partial response. Good disease control was maintained with oral alectinib treatment for 68 months in outpatient care. Currently, he is undergoing oral lorlatinib treatment. Administration of ALK inhibitors via tube using the simple suspension method is the only means of treatment for patients with ALK fusion gene-positive lung cancer facing a life-threatening crisis. Medical staff involved in lung cancer management should be proficient in this treatment method.