Neo-AEGIS (Neoadjuvant Trial in Adenocarcinoma of the Esophagus and Esophago-Gastric Junction International Study): Final primary outcome analysis.

295 Background: The optimum combination curative approach to locally advanced adenocarcinoma of the esophagus and esophago-gastric junction (AEG) remains controversial, specifically whether multimodal therapy or perioperative chemotherapy is superior. Neo-AEGIS was designed as the first randomized clinical trial (RCT) to directly compare the multimodal CROSS regimen (carboplatin/paclitaxel, 41.4Gy radiation therapy) with a modified MAGIC (epirubicin, cisplatin (oxaliplatin), 5-FU (capecitabine)) regimen (pre-2018) and more latterly the FLOT (docetaxel, 5-FU, leucovorin, oxaliplatin) regimen. Methods: 377 patients with cT 2-3 N 0-3 M 0 AEG were randomly assigned to CROSS or peri-operative chemotherapy (ECF/ECX/EOF/EOX pre-2018, FLOT option 2019/20) at 24 sites (Ireland, UK, Denmark, France, Sweden). The primary outcome was overall survival. The initial power calculation was based on CROSS superiority of 10%. This was modified after the first futility analysis (70 events) to a non-inferiority margin of 5% for peri-operative chemotherapy. Secondary end points included toxicity, pathologic measures of response, and postoperative complications as per the Esophageal Complications Consensus Group (ECCG) definitions and Clavien-Dindo severity grade. Results: Of 362 evaluable patients, 178 CROSS, 184 MAGIC/FLOT (157/27), 90% were male, median (range) age 64 (35-83), 84% were cT3, and 58% cN1. At a median (range) follow up of 34.2 (0.43-111.8) months, there were 186 deaths, 91 CROSS and 95 MAGIC/FLOT arm, with 3-year estimated survival probability of 57% (95% CI 49,64) and 55% (95% CI 47,62), respectively [(HR 1.03 (95%CI. 0.77-1.38))]. Conclusions: This RCT reveals no evidence that peri-operative chemotherapy is unacceptably inferior to multimodal therapy in the primary outcome of overall survival, notwithstanding greater proxy markers of local tumor response in the CROSS arm. Oncologic and operative outcomes were consistent with optimum modern benchmarks. These data strongly suggest non-inferiority and support equipoise in clinical decision making in modern practice. Clinical trial information: NCT01726452 . [Table: see text]