Sequential almonertinib therapy following osimertinib-induced interstitial lung disease in early-stage EGFR-mutant lung adenocarcinoma: a case report

Background: Osimertinib is the standard adjuvant therapy for resected epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC). However, its use is limited by osimertinib-induced interstitial lung disease (Osi-ILD). Case Presentation: We describe the case of a 62-year-old woman with resected stage IIB (pT1cN1M0) EGFR L858R-mutant lung adenocarcinoma who developed grade 2 Osi-ILD, characterized by new bilateral ground-glass opacities on high-resolution computed tomography (HRCT), after 3 months of adjuvant osimertinib therapy. Osimertinib was immediately discontinued, leading to complete symptomatic and radiographic resolution within 8 weeks without corticosteroid therapy. Given the high risk of ILD recurrence upon rechallenge and the suboptimal efficacy of chemotherapy, a multidisciplinary team consensus recommended switching to almonertinib (110 mg once daily). Remarkably, the patient has maintained disease-free survival without ILD relapse for 36 months. Conclusion: This case provides clinical evidence that switching to almonertinib may represent a viable and safe therapeutic strategy, thereby addressing a critical unmet need in the management of resected early-stage EGFR-mutant NSCLC after Osi-ILD.