Phase II Study of Carboplatin and Pemetrexed in Advanced EGFR-wild-type Non-squamous Non-small Cell Lung Cancer: The Central Japan Lung Study Group Trial 0906

Background: Several pre-clinical and clinical studies suggest a potential predictive role of epidermal growth factor receptor (EGFR) mutation in responsiveness to cytotoxic chemotherapy. The aim of this phase II study was to evaluate the efficacy and safety of pemetrexed-carboplatin combination as first-line chemotherapy in advanced non-squamous non-small cell lung cancer (NSCLC) limited to EGFR-wild-type cases.

Patients and methods: In this single-arm, multicenter clinical trial, patients received pemetrexed (500 mg/m(2)) and carboplatin (area under the curve=6) intravenously on day 1 every 3 weeks for three to six cycles. The objective response rate (ORR) was the primary end-point; secondary end-points included the disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety.

Results: A total of 54 patients were enrolled and 53 patients received therapy. No complete response was observed and partial response was observed in 19 (35.8%) cases, resulting in an ORR of 35.8% [95% confidence interval (CI)=23.1-50.2%]. Stable disease was observed in 20 (37.7%) patients and therefore the DCR was 73.6% (95% CI=59.7-84.7%). The median PFS was 5.4 months (95% CI=4.1-6.8 months) and the median OS was 12.7 months (95% CI=9.3-16.1 months). Treatment-related grade 3 or 4 hematological toxicities were neutropenia, leukopenia, anemia and thrombocytopenia in 35.8%, 11.3%, 30.2%, and 32.1% of patients, respectively. No grade 3 febrile neutropenia was observed, and grade 3 or 4 non-hematological toxicities were mild. There was no treatment-related death.

Conclusion: The pemetrexed-carboplatin combination was effective and well-tolerated in patients with EGFR-wild-type non-squamous NSCLC (UMIN-CTR number: UMIN000003393).