[How to make the choice in the retreatment of EGFR-TKI for advanced NSCLC patients who benefited from prior gefitinib therapy: the original drug or switching to a second EGFR-TKI?].

BACKGROUND AND OBJECTIVE: For advanced non-small cell lung cancer (NSCLC) patients who benefited from prior epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) therapy, the choice of a second TKI therapy has gradually become a new strategy for the treatment. Some investigators recommend that the second therapy should be continued with the original TKI; however, other investigators recommend the administration of another TKI. The aim of this study is to explore which choice is more reasonable.

METHODS: In retrospect, patients with advanced NSCLC or with postoperative relapse of advanced NSCLC achieved complete response (CR), partial response (PR) or stable disease (SD) in prior Gefitinib therapy, progression free survival (PFS) ≥3 months. They received repeated Gefitinib or Erlotinib at an interval of at least one month. The analysis was carried out with respect to efficacy and optimal population of the two groups.

RESULTS: A total of 61 patients were enrolled into the study, 30 in Gefitinib group and 31 in Erlotinib group. Baseline characteristics of the two groups were comparable. In the comparison between patients treated with Gefitinib and with Erlotinib, no statistical differences were seen for response rate (10% vs 22.6%, P=0.300,6), disease control rate (60% vs 74.2%, P=0.237,8), median PFS (3.0 vs 3.5 months, P=0.494,5), or median OS (8.3 vs 8.5 months, P=0.140,8). Multivariate analysis showed that in the initial dose of Gefitinib, PFS≥6 months (HR=0.317, 95%CI: 0.102-0.984, P=0.046,9). With an interval ≥3 months (HR=0.224, 95%CI: 0.071-0.713, P=0.011,3) between two doses of TKI, the risk of disease progression was reduced; but if with an interval ≥3 months (HR=0.262, 95%CI: 0.097-0.705, P=0.008,0), the risk of death was reduced.

CONCLUSIONS: Advanced NSCLC patients who benefited from prior Gefitinib therapy can benefit again either with the original drug Gefitinib or the alternative drug Erlotinib when a second TKI therapy is resumed. Such benefit is related to PFS of initial TKI therapy and time interval between two doses of TKI.