Onconic Therapeutics Presents Large-Scale Clinical Study Results for Zacubo at DDW 2026 in the US
by Jeong Donghoon
Published 06 May.2026 09:51(KST)
Large-Scale Study Conducted at Over 300 Primary Care Clinics
Involving More Than 5,500 Patients
Onconic Therapeutics announced on May 6 that it presented the results of a large-scale real-world clinical study of its potassium-competitive acid blocker (P-CAB) “Zacubo” in patients, through a poster presentation at the “Digestive Disease Week 2026 (DDW 2026)” held in Chicago, USA, from May 2 to 5 (local time).
This study was conducted to reconfirm the efficacy and safety of Zacubo in a diverse patient population in real-world clinical settings and to explore its potential to address unmet clinical needs in patients whose symptoms were not alleviated by existing treatments. The results are particularly significant as this is the first real-world data assessing the objective efficacy and safety of Zacubo in a large patient population after its market release in actual prescription environments.
DDW is a leading international academic conference in the field of gastroenterology and endoscopy, attended by more than 10,000 medical professionals from around the world to share the latest research achievements and clinical trends.
Onconic Therapeutics has been recognized in academia for providing robust clinical evidence for Zacubo, presenting results from a phase 3 clinical trial for erosive reflux disease at DDW 2024, phase 3 clinical trial results for gastric ulcers at DDW 2025, and, for the third consecutive year, a large-scale clinical study at this year’s conference.
This latest research was a multicenter study conducted from 2024 to the previous year, involving about 300 private clinics (primary care institutions) in Korea. It tracked and analyzed the objective therapeutic effect in over 500 patients with gastroesophageal reflux disease who were prescribed Zacubo 20mg for four weeks in real-world clinical settings. The study is meaningful in that it confirmed consistent results with previous clinical trials, even in general private clinic treatment and prescription environments, across multiple centers and a large patient population.
According to the analysis of GERD (heartburn and acid reflux) scores using the Reflux Disease Questionnaire (RDQ, scale 0 to 5), which evaluates typical symptoms of gastroesophageal reflux disease such as heartburn and acid reflux, the average score before taking Zacubo was 2.07. After four weeks, the average score dropped to 0.44, a decrease of 1.63 points, statistically demonstrating a significant improvement in symptoms (P < 0.0001).
Notably, a significant reduction in RDQ scores was also observed in patients whose symptoms had not improved despite taking proton pump inhibitors (PPI) or other acid suppressants. This clinical data suggests that Zacubo can address unmet needs by improving symptoms that could not be resolved by existing treatments in real-world practice.
Patients’ satisfaction with the therapeutic effect was also high. A total of 93.4% of patients responded that they were “satisfied” or “very satisfied” with the treatment effect, while the incidence rate of adverse drug reactions (ADRs) was only 0.05%, showing a favorable safety profile during the four-week observation period.
Patients cited Zacubo’s biggest competitive advantage as the convenience of taking it regardless of meals and its ability to improve symptoms unresolved by previous medications within just four weeks.
This study demonstrated, with large-scale real-world data, that “switching” to Zacubo in patients with a history of PPI or acid suppressant use can be an effective treatment strategy in actual clinical settings.
A representative from Onconic Therapeutics said, “With the efficacy of the Zacubo switching strategy proven by large-scale data, we are now able to offer a new prescription option to gastroesophageal reflux disease patients. Based on this empirical data, Zacubo’s quarterly prescription sales surpassed 20 billion won within just six quarters of its launch, and as it continues to grow as a blockbuster new drug, we plan to further expand its achievements in both the domestic and overseas markets based on these research results.”
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