Zhizhu Kuanzhong Capsule in treating patients with functional dyspepsia postprandial distress syndrome: study protocol for a multicenter, randomized, double-blind, placebo-controlled, parallel-group clinical trial

Background Functional dyspepsia (FD) is one of the most common functional gastrointestinal disorders. Based on the various symptoms present in patients with functional dyspepsia postprandial distress syndrome (FD-PDS), routine agents such as acid suppressants, prokinetic drugs, and centrally acting drugs, offer limited treatment choices with potential side effects. As a preliminary clinical trial showed that the marketed product Zhizhu Kuanzhong Capsule (ZZKZ) can improve symptoms in FD-PDS patients, our study aims to provide further evidence on the clinical efficacy and safety of ZZKZ in the treatment of patients with FD-PDS. Methods In this multicenter, randomized, patient- and investigator-blinded, placebo-controlled, parallel-group clinical trial, we will recruit patients with FD-PDS from 18 hospitals in China and Australia. The trial will enroll patients with FD-PDS based on the Rome IV diagnostic criteria. A total of 480 eligible patients will be randomized 1:1 into either ZZKZ or placebo group with 8 weeks of treatment and 4 weeks of follow-up. The primary endpoint will be measured by a self-rated Visual Analogue Score (VAS) for the degree of discomfort with both symptoms of postprandial fullness and early satiation, recorded once a day and 7 days a week. The primary analysis will aim to compare the response rate for FD-PDS VAS score between the groups before and after 8 weeks of treatment with an alpha level of 0.05 (2-sided). Discussion This trial aims to strengthen the evidence for the efficacy and safety of ZZKZ, a marketed product, in treating FD-PDS. Compared to the previous clinical trial that targeted FD-PDS, this trial will have an 8-week double-blind treatment period to investigate the effect of long-term mediation through comparison with the placebo group. Trial registration ClinicalTrials.gov NCT03825692 . Registered on 28 January 2019