713P - Neoadjuvant Gemox Followed by Gem-Based Chemoradiation for Locally advanced Unresectable Pancreatic Cancer

Abstract

ABSTRACT Purpose To asses activity, safety and secondary resectability in unresectable locally advanced pancreatic cancer (LAPC) patients (pts). Methods Unresectable LAPC pts were eligible for this phase II study. Primary endpoint was clinical benefit (CB = CR + PR + SD). A sample size of 37 pts was considered sufficient to give an 80% probability of rejecting a baseline clinical benefit rate of 55%, with an exact 5% one-sided significance test when the true disease control rate was 75%. The drug regimen would have been considered interest if at least 26 patients showed clinical benefit. Neoadjuvant induction chemotherapy (CHT) encompassed gemcitabine (GEM) 1000 mg/m2 (100-min infusion on d1) and oxaliplatin 100 mg/m2 (2-hr infusion on d2) every 2 wks, for 6 cycles. After CHT pts were restaged for surgery and/or chemoradiation (CRT) consolidation (EBRT up to a total dose of 50.4 Gy plus concomitant GEM 300 mg/m2/week). After CRT completion, pts were restaged to evaluate secondary surgery. Results From January 2005 to January 2012, 35 pts (M/F: 17/18; median age: 68 yrs, range: 46-78; ECOG PS 0-1/2: 28/7) entered the study. A median of 5 (range 1-7) CHT induction cycles were delivered. Toxicity was mild, with G3-4 neutropenia in 2 pts (6%), G3 thrombocytopenia in 1 pt (3%), G3 transaminase elevation in 5 pts (14%), and G3 diarrhea in 2 pts (6%). CHT dose was reduced or delayed in 8 and 7 pts, respectively. Nine confirmed PR and 17 SD were observed for a CB of 74% (95% confidence interval [CI], 56.7-87.5%). A decrease in serum CA 19.9 ≥50% of the baseline was observed in 14 of 23 evaluable pts. Nine-teen pts completed CRT, including 5 pts who subsequently underwent surgery; 1 pt underwent surgery without CRT. Toxicity for the CRT phase was mild, with G3 thrombocytopenia in 1 pt (3%) and G3 neutropenia in 3 pts (8%). Median overall survival (OS) and progression free survival (PFS) for all 35 patients were 10 (95% CI, 8-12) and 9 mos (95% CI, 6-12), respectively. One-yr OS and PFS rates were 26% and 30%, respectively. Conclusions The regimen under study is active and well tolerated. Although an encouraging response rate was reported, OS remains poor, calling for a better selection strategy for LAPC pts who are candidates to neoadjuvant treatment. Disclosure All authors have declared no conflicts of interest.