EGFR‒Positive Stage ⅢB NSCLC in Which Durvalumab and Osimertinib Were Ineffective after CCRT-A Case Report.

A woman in her early 70s with Stage ⅢB NSCLC and an EGFR L858R mutation underwent concomitant chemoradiotherapy (CCRT) followed by consolidation therapy with durvalumab, but no response was achieved. Considering the risk of interstitial pneumonia, osimertinib was introduced after treatment with cytotoxic antineoplastic drugs; however, the median survival was significantly lower than when osimertinib was initially administered. Immune checkpoint inhibitors (ICIs) are less effective against EGFR‒positive tumors. Furthermore, the LAURA trial demonstrated the efficacy of osimertinib after CCRT in patients with Stage Ⅲ NSCLC and EGFR‒positive tumors. Using durvalumab after CCRT in EGFR‒positive patients may hinder using osimertinib, an effective therapeutic agent.