Safety and efficacy of afatinib for the treatment of non-small-cell lung cancer following osimertinib-induced interstitial lung disease: A retrospective study.

Background Osimertinib is one of the first-line treatments for advanced non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. However, the occurrence rate of osimertinib-induced interstitial lung disease (ILD) is particularly high in Japanese patients and little information on subsequent cancer treatment options after recovery from osimertinib-induced ILD is currently available. Thus, this study aims to determine the safety and efficacy of afatinib for the treatment of NSCLC following osimertinib-induced ILD. Methods We retrospectively investigated the clinical courses of all NSCLC patients with EGFR mutations at our facility between August 2018 and September 2019, who received osimertinib as first-line treatment and were subsequently treated with afatinib after developing osimertinib-induced ILD. Results Forty-two patients received osimertinib treatment at our facility during the study period, and four patients received afatinib after developing osimertinib-induced ILD. All events of ILD improved either spontaneously or with steroid therapy before the initiation of afatinib. For the four patients who were retrospectively reviewed, the overall response rate to afatinib therapy was 75%, and the disease control rate was 100%. During the study period, no ILD recurrence was observed in any of the four patients. Conclusions According to our study findings, afatinib treatment after osimertinib-induced ILD is considered safe and effective and it can be used as one of the treatment options for NSCLC following osimertinib-induced ILD.