Pemetrexed plus platinum versus pemetrexed alone in non-small cell lung cancer patients who have progressed after first-line EGFR TKIs

Objectives: After failure of first-line epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) in patients with non-small cell lung cancer (NSCLC) harboring EGFR-activating mutation, platinum based combination chemotherapy is recommended. However, it is still unknown which chemotherapeutic regimens result in better outcomes. Materials and methods: A total of 63 patients who were treated with pemetrexed or pemetrexed/platinum chemotherapy after first line EGFR TKI therapy at Samsung Medical Center were included in our analysis. Baseline clinical characteristics, response rate, toxicities and survival outcomes were compared between the two groups. Results: Among 63 patients, 29 were treated with pemetrexed (P) alone and 34 were treated with pemetrexed and platinum combination (PC) therapy. The median age, sex and smoking history was not different between the two groups. The overall response rate and disease control rate was 25.9%/44.4% for the P group and 43.5%/75.0% for the PC group (p = 0.154 in response rate, p = 0.017 in disease control rate). Grade 2 or 3 neutropenia was noted only for the PC group (0% vs. 18.8%, p = 0.049). For progression-free survival (PFS), patients treated with PC had more favorable outcomes than patients treated with P alone, although the difference was not statistically significant (5.2 vs. 2.7 months, PC vs. P; p= 0.096). Conclusions: Based on this retrospective analysis, platinum combination with pemetrexed resulted in a better disease control rate and a tendency toward prolongation of progression-free survival in NSCLC patients who progressed after first-line EGFR TKIs.