A modified triplet combination of docetaxel, oxaliplatin, and fluorouracil for gastric cancer (GC) with peritoneal carcinomatosis (PC) and inoperable malignant bowel obstruction (MBO): A multi-center, non-randomized, three-cohort, phase II trial (Zhen Jing).

Abstract

TPS426 Background: For GC, PC is ranked as the most common in relapse and the second common in metastasis. MBO is a frequent and preterminal complication of PC, which has been reported to have a poor overall survival (OS) of only 3 months without effective treatment. Medical therapy of gastroenteric drainage and symptomatic drugs is the cornerstone management for MBO, just alleviating symptoms. Interventional therapy and surgery are effective but indicated in limited patients (pts) with strict selection. Chemotherapy is the mainstay treatment for metastatic GC but its role in MBO is poorly defined. Only a few retrospective studies are available, showing conflicting results on obstruction clearance (OC) and OS. Methods: We are conducting the Zhen Jing trial in five Chinese centers to investigate the tolerability and efficacy of a dose-sense regimen of docetaxel, oxaliplatin and fluorouracil in MBO from GC. Cohort A is for pts in first-line setting. Cohort B is for second-line setting. Cohort C is for pts who have failed to two or more regimens. Eligible pts will receive the same experimental regimen every 28 days: docetaxel 25 mg/m2 on days 1, 8, 15; oxaliplatin 85 mg/m2 on days 1, 15; fluorouracil 1200 mg/m2 24-hour infusion on days 1, 8, 15. A Simon's two-stage optimal design is applied (table below). The primary endpoint is 60-day OC rate. Secondary endpoints are 30-day OC rate, time to OC, OC duration, safety, overall survival and quality of life. Till July 2023, a total of 34 pts has been enrolled (16 in cohort A, 9 in cohort B, 9 in cohort C). Inclusion Criteria: 18-75 years old; Eastern Cooperative Oncology Group performance status ≤ 3; adenocarcinoma of stomach or gastroesophageal junction; peritoneal carcinomatosis established by imaging data or pathological evidence; MBO below the Treitz ligament based on clinical grounds or radiological findings; inappropriate for operation judged independently by two surgeons; written informed consent. Exclusion Criteria: Treated by a combination regimen containing all the study drugs; allergy to any of the study drugs; HER-2 gene overexpression; high microsatellite instability or mismatch repair deficiency; strangulated obstruction; active gastrointestinal bleeding; uncontrolled active infection; unstable heart diseases; severe lung diseases; central nervous system diseases; concomitant cerebral or meningeal metastasis; surgery or stent are required. Clinical trial information: NCT04840264 . [Table: see text]