Phase II Study of Concurrent Pemetrexed, Cisplatin, and Radiation Therapy for Stage IIIA/B Unresectable Non–Small Cell Lung Cancer

Introduction Concurrent thoracic radiation and platinum-based chemotherapy is the standard of care for treatment of unresectable stage IIIA-IIIB non–small-cell lung cancer (NSCLC), but the optimal drug regimen has not been established. Patients and Methods In the present single-arm phase II trial, patients with previously untreated, unresectable stage IIIA-IIIB NSCLC (all histologic types) were treated with pemetrexed-cisplatin (500 mg/m 2 intravenously on days 1 and 22, 20 mg/m 2 intravenously on days 1-5 and days 22-26) concurrent with radiotherapy (61-66 Gy in 31-35 fractions), followed by 2 cycles of consolidation pemetrexed-cisplatin (75 mg 2 ) therapy. The primary endpoint was the 1-year overall survival (OS) rate. The study treatment was considered active if the 1-year OS rate was ≥ 70%. Results A total of 39 patients, including 6 from the previous phase I trial who had been treated at the recommended phase II dose, were eligible for analysis. The most common drug-related grade 3 to 4 adverse events during the concurrent phase were hematologic and 5.1% of patients experienced grade 3 esophagitis. The response rate was 45.9% (17 of 37 patients), with no complete responses. The 1-, 2-, and 3-year OS survival rates were 79.5%, 56.4%, and 46.2%, respectively. The median OS, time to progressive disease, and progression-free survival was 30.3, 13.7, and 11.8 months, respectively. Conclusion Full-dose cisplatin and pemetrexed can be administered concurrently with conventional doses of thoracic radiation. The median and 1-year OS rates were favorable compared with published clinical trials in this setting. The regimen was tolerable, and the toxicity profile was consistent with the known toxicity profiles of pemetrexed, cisplatin, and radiation.