A molecular biomarker targeted approach to adjuvant therapy for resected pancreatic adenocarcinoma: Results of a phase II prospective trial.

Abstract

230 Background: Standard adjuvant treatment for resected pancreatic adenocarcinoma is gemcitabine (Gem) (CONKO-001 trial: Gem vs placebo DFS 13.4 vs 6.7 mo; p<0.001; OS 22.8 vs 20.2 mo; p=0.01). Adding cisplatin (Cis) to Gem has shown increased response rates in the metastatic setting. This benefit may be inhibited by high expression of excision repair cross-complementing gene–1 (ERCC1), the key enzyme in nucleotide excision repair. This Phase II prospective trial assesses outcomes of patients treated with adjuvant Gem/Cis chemotherapy, stratifying results by tumor ERCC1 expression. Methods: Patients with resected pancreatic adenocarcinoma at a single institution were enrolled from 2010-2013. Initially, patients received Gem (1000 mg/m2) / Cis (50 mg/m2) Day 1/8/15, Q28d for 6 cycles. After enrolling 5 pts, this was modified to Day 1/15 due to toxicity. Two dose reductions were permitted. Intent to treat analyses were conducted. Tumor ERCC1 expression was evaluated by immunohistochemistry and dichotomized into low and high expression groups. Primary outcomes were RFS and OS stratified by ERCC1 expression. Results: Of 22 pts, 16 (73%) had Stage IIB disease, 5 (23%) Stage IIA, and 1 (4%) Stage IA. Thirteen (59%) completed all 6 cycles of therapy, of whom 9 required dose reduction. Of the remaining 9 pts, 4 completed >68% of intended therapy. Grade 3 and 4 toxicity occurred in 13 pts (59%); neutropenia was most common (n=9;41%). Median follow-up was 37.5 mo. Median RFS was 16.7 mo, and OS was 35.5 mo. ERCC1 tumor expression data were available for 20 pts: 15 low (75%) and 5 high (25%). Low compared to high ERCC1 was not associated with improved RFS (12.4 vs 16.7 mo; p=0.68) or OS (Median not reached vs 21.6 mo; p=0.22). Conclusions: Adjuvant gemcitabine/cisplatin is tolerated by patients with resected pancreatic adenocarcinoma. RFS and OS for Gem/Cis appear promising compared to historic control. Tumor ERCC1 expression can be reliably evaluated, and low expression is present in the majority of patients. Further prospective trials evaluating Gem/Cis as an adjuvant regimen and ERCC-1 as a biomarker in resected pancreatic adenocarcinoma are warranted. Clinical trial information: NCT01188109.