fig1

Figure 1. This scheme represents the sequence of therapeutic regimens in EGFR-mutated NSCLC. Tumors are treated with first-line agents erlotinib, gefitinib, or afatinib. Alternatively, the second-line osimertinib is applied directly or as actual second-line therapy. C797S may appear as further mutation of EGFR followed by progress and eventually by rescue chemotherapy. First-line osimertinib is rendered inactive by loss of T790M and the patients may be further treated by targeted agents against alternative pathway modulators and, upon progress, by rescue chemotherapy. Switch to a SCLC histotype may occur from both branches of therapy and result in cancer resistance and progress. SCLC: small cell lung cancer; EGFR: epidermal growth factor receptor; NSCLC: non-small cell lung cancer