Background::The pharmacokinetic and clinical behaviors of many proton pump inhibitors (PPIs) in peptic ulcer treatment are altered by CYP2C19 genetic polymorphisms. This non-inferiority study evaluated the efficacy and safety of the novel PPI anaprazole compared with rabeprazole. We also explored the influence of Helicobacter pylori ( H. pylori) infection status and CYP2C19 polymorphism on anaprazole. Methods::In this multicenter, randomized, double-blind, double-dummy, positive-drug parallel-controlled, phase III study, Chinese patients with duodenal ulcers were randomized 1:1 to receive rabeprazole 10 mg + anaprazole placebo or rabeprazole placebo + anaprazole 20 mg once daily for 4 weeks. The primary efficacy endpoint was the 4-week ulcer healing rate assessed by blinded independent review. Secondary endpoints were the proportion of patients with improved overall and individual duodenal ulcer symptoms at 4 weeks. Furthermore, exploratory subgroup analysis of the primary endpoint by H. pylori status and CYP2C19 polymorphism was conducted. Adverse events were monitored for safety. Non-inferiority analysis was conducted for the primary endpoint. Results::The study enrolled 448 patients (anaprazole, n = 225; rabeprazole, n = 223). The 4-week healing rates were 90.9% and 93.7% for anaprazole and rabeprazole, respectively (difference, -2.8% [95% confidence interval, -7.7%, 2.2%]), demonstrating non-inferiority of anaprazole to rabeprazole. Overall duodenal ulcer symptoms improved in 90.9% and 92.5% of patients, respectively. Improvement rates of individual symptoms were similar between the groups. Healing rates did not significantly differ by H. pylori status or CYP2C19 genotype for either treatment group. The incidence of treatment-emergent adverse events was similar for anaprazole (72/220, 32.7%) and rabeprazole (84/219, 38.4%). Conclusions::The efficacy of anaprazole is non-inferior to that of rabeprazole in Chinese patients with duodenal ulcers.Registration::ClinicalTrials.gov, NCT04215653.