A phase III randomized study of gemcitabine and cisplatin with or without PF-3512676 (TLR9 agonist) as first-line treatment of advanced non-small-cell lung cancer

Background: This open-label phase III study assessed the addition of Toll-like receptor 9-activating oligodeoxynucleotide PF-3512676 to gemcitabine/cisplatin chemotherapy in patients with non-small-cell lung cancer (NSCLC). Patients and methods: Chemotherapy-naive patients with stage IIIB or IV NSCLC were randomized (1 : 1) to receive six or fewer 3-week cycles of i.v. gemcitabine (1250 mg/m(2) on days 1 and 8) and cisplatin alone (75 mg/m(2) on day 1, control arm) or combined with s.c. PF-3512676 0.2 mg/kg on days 8 and 15 of each chemotherapy cycle and weekly thereafter until progression or unacceptable toxicity (experimental arm). No crossover was planned. The primary end point was overall survival (OS). Results: A total of 839 patients were randomized. Baseline demographics were well balanced. Median OS (11.0 versus 10.7 months; P = 0.98) and median progression-free survival (PFS) (both 5.1 months) were similar between groups. Grade >= 3 hematologic adverse events (AEs), injection-site reactions, and influenza-like symptoms were more frequently reported among patients receiving PF-3512676. At the first-interim analysis, the Data Safety Monitoring Committee recommended study discontinuation. Administration of PF-3512676 was halted based on efficacy futility and increased grade >= 3 AEs (experimental arm). Conclusions: Addition of PF-3512676 to gemcitabine/cisplatin chemotherapy did not improve OS or PFS but did increase toxicity.