LAUSR

INTRODUCTION The third-generation tyrosine kinase inhibitor (TKI) osimertinib is recommended as a first-line treatment in advanced non-small cell lung cancer harboring an activating mutation of Epidermal Growth Factor Receptor (EGFR). Adverse pulmonary events related to osimertinib exposure have been reported, primarily in Japanese patients. They rarely occur in the Caucasian population. OBSERVATION Herein we report two clinical cases of osimertinib-induced lung toxicities in patients diagnosed with advanced lung adenocarcinoma harboring an EGFR mutation. In the first case, interstitial pneumonia was asymptomatic and evolved favorably after osimertinib discontinuation. The second patient presented a more extensive form of lung injuries and despite systemic corticosteroid therapy, the evolution was fatal. CONCLUSION Osimertinib-related lung toxicities remain exceptional. While most forms are mild, consideration of TKI treatment discontinuation may be necessitated. Introduction of another TKI or rechallenge with osimertinib might be considered along with corticosteroid therapy if necessary. Diffuse alveolar damage is a pejorative prognostic factor.