BACKGROUND Brigatinib is used for anaplastic lymphoma kinase (ALK)-positive lung cancer treatment, and some research showed it was useful in treating triple-mutant epidermal growth factor receptor lung cancer. Clinical trials have shown some potential pulmonary toxicities of brigatinib. The early-onset pulmonary events (EOPEs) of brigatinib are associated with high dosage and older age. The successful treatment of EOPEs with steroids was reported. We present the case of a patient with epidermal growth factor receptor L858R/cis-T790M/cis-C797S triple mutations who developed EOPEs after using brigatinib together with afatinib, and the patient was successfully treated with high-dose steroids. CASE REPORT A 54-year-old woman with underlying stage IV lung adenocarcinoma, ECOG score of 0, was treated with brigatinib and afatinib due to disease progression secondary to L858R/cis-T790M/cis-C797S triple mutations. After starting brigatinib and afatinib, she developed dyspnea and dry cough within 2 days and was intubated due to hypercapnic respiratory failure. The chest X-ray showed bilateral interstitial infiltrates while chest computed tomography (CT) showed bilateral ground-glass opacities. EOPEs were suspected and methylprednisolone was prescribed. The oxygenation of the patient improved and her chest CT showed complete resolution after 2 weeks of steroid treatment. CONCLUSIONS This is the first reported case in which brigatinib combined with afatinib induced EOPEs in a patient with triple-mutant epidermal growth factor receptors of lung cancer. Use of doubled tyrosine kinase inhibitors may result in increased risk of pulmonary toxicities that require high alertness, and the respiratory symptoms should be monitored closely after prescription. The early treatment of EOPEs with high-dose steroids resulted in remarkable improvement.