Successful Osimertinib Rechallenge with Steroid Therapy after Osimertinib-induced Interstitial Lung Disease.

A 62-year-old male with lung adenocarcinoma harboring an exon 19 deletion in the Epidermal growth factor receptor (EGFR) was treated with EGFR-tyrosine kinase inhibitors (TKIs) and several cytotoxic agents. After administering a fifth-line chemotherapy regimen, a liver biopsy revealed a diagnosis of recurrence with a T790M mutation. After an 82-day course of osimertinib therapy, the patient developed osimertinib-induced interstitial lung disease (ILD). Osimertinib was discontinued, and oral prednisolone was started. The ILD quickly improved, but liver metastases progressed and osimertinib was restarted concurrently with prednisolone. The patient showed neither disease progression nor a recurrence of ILD at 5 months. In situations in which no alternative treatment is available, osimertinib rechallenge should thus be considered as an alternative treatment.