The primary objective of this clinical study is to evaluate the efficacy and safety of nanocrystalline megestrol acetate combined with a 5-HT3 receptor antagonist for the prophylaxis of nausea and vomiting caused by moderately emetogenic chemotherapy drugs.
The study population consists of gastric adenocarcinoma patients who are scheduled to receive their first course of moderately emetogenic chemotherapy (PD-1/PD-L1 immune checkpoint inhibitors combined with the CAPOX regimen). This study is divided into two phases. The first phase is a single-arm study design, with the primary objective of preliminarily assessing the efficacy and safety of nanocrystalline megestrol acetate combined with a 5-HT3 receptor antagonist for the full-course management of nausea and vomiting caused by moderately emetogenic chemotherapy drugs. The second phase will adopt a randomized, controlled, multicenter trial design. Based on the efficacy and safety data from the first phase, the investigators will optimize the trial design (primarily including the primary endpoint and sample size calculation) to evaluate the efficacy and safety of nanocrystalline megestrol acetate compared with dexamethasone, each combined with a 5-HT3 receptor antagonist, for the prevention of nausea and vomiting caused by moderately emetogenic chemotherapy drugs.