Phase II trial of carboplatin and pemetrexed as first-line chemotherapy for non-squamous non-small cell lung cancer, and correlation between the efficacy/toxicity and genetic polymorphisms associated with pemetrexed metabolism: Hokkaido Lung Cancer Clinical Study Group Trial (HOT) 0902.

Purpose: This phase II study evaluated the response rate (RR) and safety of combination therapy with carboplatin (CBDCA) and pemetrexed (PEM) in Japanese patients with non-squamous non-small cell lung cancer (non-sq NSCLC). Further, the relationship between therapy efficacy/toxicity and genetic polymorphisms associated with PEM metabolism was analyzed.

Methods: Forty-one patients received CBDCA at a dose targeting an area under the concentration-time curve of 5 mg/mL × min and PEM of 500 mg/m(2) on day 1 every 3 weeks. Single-nucleotide polymorphisms of the thymidylate synthase (TYMS) coding gene, the variable number of tandem repeat (VNTR) in the TYMS, and the methylenetetrahydrofolate reductase (MTHFR) coding gene were analyzed.

Results: The overall RR was 36.6 %. Median progression-free survival and median survival time were 4.7 months [95 % confidence interval (CI) 3.9-5.6 months] and 16.2 months (95 % CI 6.1-26.2 months), respectively. Epidermal growth factor receptor gene mutations were detected in 6 patients (14.6 %). The VNTR in the TYMS significantly correlated with anemia (p = 0.047) and thrombocytopenia (p = 0.038).

Conclusions: This combination therapy was effective and tolerable in patients with advanced non-sq NSCLC. The VNTR in the TYMS appears to be a predictive factor for anemia and thrombocytopenia in patients treated with this regimen.