Objectives: Sequential combination of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) and chemotherapy has shown greater benefits than either treatment alone in non-small-cell lung cancer (NSCLC). In this follow-up of the ENSURE study, we evaluated progression-free survival (PFS) with first-line erlotinib followed by chemotherapy at progression versus the inverse treatment sequence in 175 Chinese patients with EGFR mutation-positive NSCLC.
Materials and methods: Forty-five of the 175 patients included in the follow-up analysis experienced progressive disease (PD). Those with PD on first-line erlotinib (n = 24) received gemcitabine/cisplatin while those who failed first-line chemotherapy (n = 21) received erlotinib until second-line PD. The primary endpoint was PFS in the crossover subpopulation. Post-hoc analysis of survival outcomes was also measured for the overall population of 175 Chinese patients.
Results: Among patients who crossed over at progression, PFS was comparable between those who received second-line erlotinib and those who received second-line chemotherapy (median, 26.3 months and 23.4 months, respectively; P = 0.529). Regardless of the sequence in which the therapies were administered, patients in the crossover treatment subgroup benefited from either second-line therapy after progression with a median overall survival of 51.6 months versus 23.0 months achieved among patients in the non-crossover treatment subgroup. Post-hoc biomarker analyses of Kaplan-Meier survival curves and Cox regression showed that survival benefits with either treatment sequence were similar between patients with circulating free DNA EGFR mutations in exons 19 and 21; however, those with undetectable mutations achieved significantly greater survival benefits.
Conclusion: In advanced EGFR mutation-positive NSCLC, first-line erlotinib followed by chemotherapy at progression demonstrated comparable PFS benefit with the inverse treatment sequence, irrespective of mutation subtype. Utilizing both EGFR-TKIs and chemotherapy, irrespective of the sequence, maximizes survival benefits for patients.
Keywords: Asian; Chemotherapy; EGFR; Erlotinib; Non small cell lung cancer.
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