Introduction: Pemetrexed is synergistic with gemcitabine in preclinical models of non-small cell lung cancer (NSCLC). The optimal dose and utility of gemcitabine and pemetrexed was evaluated in a dose-escalating study.
Methods: The phase 1 study included patients with advanced tumors, whereas the phase 2 study included patients with locally advanced or metastatic NSCLC. Gemcitabine was infused over 30 minutes, followed by pemetrexed administered over 10 minutes on day 1 of a 14-day cycle. Treatment continued for 12 cycles or until disease progression. All patients received folic acid, Vitamin B12, and steroid prophylaxis.
Results: Maximum tolerated dose was gemcitabine 1500 mg/m, followed by pemetrexed 500 mg/m. Fifty-three patients (29 male, 24 female) were enrolled in the phase 2 study. Response rate was 20.8% (95% CI: 0.108-0.341), and the clinical benefit rate (CR + PR + SD) was 64.2%. Median time to disease progression was 4.6 months (95% CI: 2.79-6.18), median survival was 10.1 month (95% CI: 5.95-14.09, censorship = 20.75%), and 1-year survival was 41.0%. Common grade 3 or 4 adverse events (% of patients) were neutropenia (28.3%), fatigue (22.6%), and febrile neutropenia (9.4%).
Conclusions: Twice-monthly gemcitabine and pemetrexed was well tolerated, with overall survival and clinical benefit indicating disease activity in NSCLC patients.