Programme Hospitalier Recherche Clinique, Institut Pasteur, Inserm, French Public Health Agency.

LBA4003 Background: CRT in patients with LAPC controlled after induction CT could be superior to continuing CT (Huguet, JCO 2007). The role of erlotinib is unknown. We aimed to define the role of 1) CRT after disease control with gemcitabine, 2) erlotinib in LAPC. Methods: LAPC PS 0-2 patients were first randomized to gemcitabine alone or plus erlotinib 100 mg/d for 4 months (R1, stratification: center, PS). Patients with controlled disease were then randomized to 2 additional months of CT (Arm 1) or CRT (Arm 2) 54 Gy and capecitabine 1600 mg/m2/d (R2, stratification: center, initial arm). Patients receiving erlotinib at R1 had maintenance with this drug after protocol completion. Quality control for radiotherapy included dummy runs and assessment of treated patients. Primary objective: overall survival (OS) in R2 patients. Secondary objectives: role of erlotinib on OS (R1), tolerance, predictive markers, and circulating tumor cells. Taking into account a 30% progression rate between R1 and R2, and 5% lost to follow-up, 722 patients were required to observe 392 deaths to show a median OS increase from 9 to 12 m (HR=0.75) in the CRT arm (2 sided α=5% and β=20%) with planned interim analyses using alpha spending function and O’Brien Fleming boundaries (to reject H0 or H1). Kaplan-Meier, log rank and univariate Cox tests were used. Results: From 442 pts included for R1, 269 pts reached R2 (arm1:136; arm 2:133). Main baseline characteristics in arms 1/2: female 44%/56%, mean age 63/62, head tumor 65%/62%, PS 0 56%/48%. After a median follow-up of 36 m, 221 deaths had occurred allowing the planned interim analysis (information fraction 56.4%). OS in R2 pts was 16.5 m [15.5-18.5] and 15.3 m [13.9–17.3] in arms 1 and 2, respectively (HR=1.03 [0.79-1.34], p=0.83). IDMC has confirmed that the futility boundary for the hypothesis of CRT superiority was crossed and considered this as the final analysis of the study. Conclusions: Administering CRT is not superior to continuing CT in patients with controlled LAPC after 4 months of CT. Clinical trial information: NCT00634725.

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