The efficacy and tolerability of combining pemetrexed-based chemotherapy with gefitinib in the first-line treatment of non-small cell lung cancer with mutated EGFR: A pooled analysis of randomized clinical trials

BACKGROUND: Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) monotherapy is the standard of care in treating advanced non-small cell lung cancer (NSCLC). Nevertheless, whether adding pemetrexed-based chemotherapy to EGFR-TKI targeted therapy furtherly prolongs survival outcomes and improves responses remains controversial. Therefore, we conducted this pooled analysis to compare the efficacy and tolerability between gefitinib plus pemetrexed-based chemotherapy and gefitinib alone in the first-line treatment of advanced NSCLC patients with mutated EGFR. METHODS: We systematically searched PubMed, Web of Science, Embase, and Cochrane CENTRAL on June 23, 2022. Eligible studies were registered randomized clinical trials comparing gefitinib plus pemetrexed-based chemotherapy with gefitinib alone. The primary outcomes were overall survival (OS) and progression-free survival (PFS). Objective response rate (ORR), disease control rate (DCR), and discontinuation rate (DR) were explored as secondary outcomes. RESULTS: Eight studies within five randomized clinical trials were eligible. Gefitinib combined with pemetrexed-based chemotherapy significantly prolonged OS (hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.37–0.89, p = 0.0125) and PFS (HR 0.52, 95% CI 0.39–0.70, p < 0.0001) versus gefitinib alone. In subgroup analysis, patients with EGFR exon 19 deletion and exon 21 L858R could benefit from the addition of pemetrexed-based chemotherapy to gefitinib in terms of PFS (EGFR exon 19 deletion: HR 0.50, 95% CI 0.34–0.75, p = 0.0008; EGFR exon 21 L858R: HR 0.46, 95% CI 0.26–0.82, p = 0.0079) but not OS. In addition, ORR was improved after the administration of gefitinib plus pemetrexed-based chemotherapy against gefitinib (odds ratio [OR] 1.91, 95% CI 1.44–2.55, p < 0.0001). Both strategies showed comparable DCRs (OR 1.46, 95% CI 0.94–2.26, p = 0.0952) and DRs (risk ratio [RR] 2.80, 95% CI 0.69–11.44, p = 0.1509). CONCLUSION: Compared with gefitinib alone, combining pemetrexed-based chemotherapy with gefitinib significantly improved OS and PFS in advanced EGFR-mutant NSCLC patients with acceptable tolerability. However, the accurate sub-population who could have OS benefits requires further validation.