Randomized phase II clinical trial comparing tremelimumab (CP-675,206) with best supportive care (BSC) following first-line platinum-based therapy in patients (pts) with advanced non-small cell lung cancer (NSCLC)

8071 Background: Pts diagnosed with advanced NSCLC with good performance status typically receive platinum-based chemotherapy; however, no approved maintenance therapy exists. Tremelimumab, a fully human anti-CTLA4 mAb, is associated with durable responses in some pts with metastatic melanoma. Methods: This open-label, randomized, multicenter, phase II clinical trial evaluating efficacy and safety of tremelimumab as maintenance therapy was conducted in pts with locally advanced or metastatic NSCLC with ECOG performance status ≤1. Pts treated with ≥4 cycles of first-line platinum-based therapy resulting in either stable disease (SD) or response per RECIST were eligible and were randomized 3–6 weeks after prior therapy. Pts received 15 mg/kg IV tremelimumab Q90D or BSC until disease progression. Primary endpoint was progression-free survival (PFS) at 3 months. Secondary endpoints included safety, objective response rate, and 1-year survival. Results: Eighty-seven pts received tremelimumab (n=44) or BSC (n=43). Nine (20.9%; 90% CI: 11.4%, 33.7%) pts receiving tremelimumab and 6 (14.3%; 90% CI: 6.4%, 26.3%) pts receiving BSC were progression free at 3 months. Among pts receiving tremelimumab, there were 2 (4.8%) partial responses and 7 (16.6%) SDs, compared with 0 and 6 (14.3%) pts receiving BSC, respectively. Treatment-related adverse events (AEs) were observed in 27 (61.4%) pts receiving tremelimumab and 3 (7.0%) receiving BSC. Nine pts (20.5%) receiving tremelimumab reported grade 3 or 4 AEs compared with 0 patients receiving BSC. The most common grade 3 or 4 AEs attributed to tremelimumab were diarrhea and colitis (n=4, 9.1%). Conclusions: In pts with advanced NSCLC and good performance status receiving platinum-based first-line therapy, single-agent tremelimumab was tolerable, with safety consistent with prior studies. Although PFS analysis did not demonstrate superiority of tremelimumab over BSC, the 4.8% objective response rate seen only in the investigational arm may support future combination studies. Analysis of 1-year survival is forthcoming. [Table: see text]