Randomized, Phase II study of pemetrexed plus bevacizumab versus pemetrexed alone after treatment with cisplatin, pemetrexed, and bevacizumab in advanced non‐squamous, non‐small cell lung cancer: TORG (thoracic oncology research group) 1321

Introduction Cisplatin plus pemetrexed followed by pemetrexed is an efficacious platinum combination regimen for advanced non‐squamous, non‐small cell lung cancer (NSCLC). Data regarding the addition of bevacizumab, especially in maintenance treatment, are insufficient. Methods Eligibility criteria included: no prior chemotherapy; advanced, non‐squamous, NSCLC; performance status ≤1; and epidermal growth factor receptor mutation‐negative. Patients (N = 108) received induction chemotherapy with cisplatin, pemetrexed, and bevacizumab every 3 weeks for four cycles, and tumor response was needed to confirm four‐week response duration. Patients with at least stable disease were randomized to pemetrexed/bevacizumab or pemetrexed alone. The primary endpoint was progression‐free survival (PFS) after induction chemotherapy. Myeloid‐derived suppressor cell (MDSC) counts of peripheral blood samples were also analyzed. Results Thirty‐five patients each were randomized to the pemetrexed/bevacizumab group and the pemetrexed alone group. PFS was significantly better in the pemetrexed/bevacizumab group than in the pemetrexed alone group (7.0 vs. 5.4 months, hazard ratio: 0.56 [0.34–0.93], log‐rank p = 0.023). In patients with partial response to induction therapy, median overall survival was 23.3 months in the pemetrexed alone group and 29.6 months in the pemetrexed/bevacizumab group (log‐rank p = 0.077). Pretreatment monocytic (M)‐MDSC counts tended to be greater in the pemetrexed/bevacizumab group with poor PFS than in those with good PFS (p = 0.0724). Conclusions Addition of bevacizumab to pemetrexed as maintenance therapy prolonged PFS in patients with untreated, advanced, non‐squamous NSCLC. Furthermore, an early response to induction therapy and pretreatment M‐MDSC counts may be related to the survival benefit of the addition of bevacizumab to the combination of cisplatin and pemetrexed.