Emerging Risk Profile of Lung Cancer Therapy: Diffuse AlveolarHemorrhage from Osimertinib

Osimertinib is an oral epithelial growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) used primarily in the treatment ofmetastatic non-small cell lung cancer. It is usually well tolerated with less than 5% of patients developing significant pulmonarytoxicity from the medication, typically within thefirst few months after initiation. Previously reported pulmonary adversereactions include pneumonitis (nonspecific interstitial pneumonia or other forms of acute interstitial process),fleetingasymptomatic infiltrates on imaging, and eosinophilic pneumonia. We present an interesting case of a 65-year-old female withrecurrent metastatic adenocarcinoma of the lung, treated with Osimertinib for 4 months, who developed a previouslyunreported toxicity of diffuse alveolar hemorrhage (DAH) requiring mechanical ventilatory support