Dose-escalation study of pemetrexed in combination with carboplatin followed by pemetrexed maintenance therapy for advanced non-small cell lung cancer

Abstract 

Introduction

The primary objectives of this study were to determine the recommended dose of pemetrexed and carboplatin in patients with chemo-naive advanced non-small cell lung cancer (NSCLC).

Methods

Patients received escalated doses of carboplatin area under the concentration–time curve (AUC) of 5 (cohort 1) or 6 (cohort 2) and pemetrexed 500mg/m² every 3 weeks for six cycles. For patients with objective response and stable disease, pemetrexed were continued until disease progression or unacceptable toxicity.

Results

In cohort 1, a dose-limiting toxicity (DLT) was observed in one of the six patients: grade 4 thrombocytopenia. No DLTs were seen in the first 6 patients of cohort 2, and thus the combination of pemetrexed 500mg/m² plus carboplatin at AUC 6 was determined as the recommended dose. Among a total of 20 patients, 8 patients received a median of four cycles of pemetrexed monotherapy in a maintenance setting without unexpected or cumulative toxicities. No complete responses and 12 partial responses were observed, giving an overall response rate of 60.0% [95% confidence interval (CI), 36.1–80.9%]. Median progression-free survival time for all patients was 7.6 months (95% CI: 4.8–8.0 months).

Conclusions

Pemetrexed 500mg/m² plus carboplatin AUC 6 combination therapy followed by pemetrexed maintenance therapy, is generally tolerable, and shows encouraging antitumor activity in chemotherapy-naive patients with advanced NSCLC.

Keywords: Pemetrexed, Carboplatin, Dose-escalation, First-line therapy, Maintenance therapy, NSCLC