[E-Daily Reporter KIM SAE-MI ] Daewon Pharmaceutical’s ( DaewonPharmaceutical(003220)) new potassium-competitive acid blocker (P-CAB) drug “Padoprazan” (DW4421) met its primary endpoint in a domestic Phase 3 clinical trial. Having demonstrated non-inferiority compared to the existing proton pump inhibitor (PPI) “Esomeprazole,” the company plans to submit a marketing authorization application by the end of the year.

DaewonPharmaceutical announced on the 29th that its Phase 3 clinical trial of padoprazan, conducted on 328 patients with erosive gastroesophageal reflux disease, confirmed non-inferiority of both dosage levels compared to the comparator drug.

This clinical trial was conducted at 22 medical institutions in South Korea, including Incheon St. Mary’s Hospital of The Catholic University of Korea, using a randomized, double-blind, active-controlled, parallel-group design. It compared the efficacy and safety of the 20 mg and 40 mg padoprazan groups with the 40 mg esomeprazole group.

Patients were administered the test drug for 4 weeks, and treatment was extended up to 8 weeks if esophageal mucosal lesions had not fully healed. The primary endpoint was the complete healing of esophageal mucosal lesions, as confirmed by endoscopy.

Analysis of the patient population adhering to the clinical trial protocol (PP) showed that the two-sided 95% confidence interval for the difference in mucosal healing rates between the padoprazan 40 mg group and the esomeprazole group was -2.50 to 6.87 percentage points (p). For the 20 mg padoprazan group, the range was -3.90 to 6.58 percentage points.

For both doses, the lower limit of the confidence interval exceeded the pre-specified non-inferiority margin of -10.0 percentage points. Consequently, padoprazan demonstrated non-inferiority compared to esomeprazole and achieved the primary endpoint of the Phase 3 clinical trial.

However, these results demonstrate non-inferiority compared to existing treatments; they do not confirm superior therapeutic efficacy. The topline data released this time did not include detailed information such as the actual mucosal healing rates for each treatment group, the early healing rate at Week 4, or the results from the Full Analysis Set (FAS).

In the safety evaluation, the incidence of adverse drug reactions was 4.59% (5 patients) in the 40 mg padoprazan group, 3.74% (4 patients) in the 20 mg padoprazan group, and 3.70% (4 patients) in the esomeprazole group. There was no statistically significant difference in incidence rates between the treatment groups (P=1.0000), and no serious adverse events occurred.

Based on these clinical results, DaewonPharmaceutical plans to conduct a detailed analysis of efficacy and safety and submit a final results report to the Ministry of Food and Drug Safety within the year to apply for marketing authorization. A Phase 3 clinical trial targeting non-erosive gastroesophageal reflux disease (NERD) is currently underway, and the company is also preparing clinical trials to secure additional indications.

If padoprazan obtains marketing authorization, it will enter the domestic P-CAB market as a latecomer. The domestic P-CAB market is currently contested by “K-Cap” from HK inno.N Corporation(195940), “Pexuclu” from DAEWOONGPHARMACEUTICAL(069620), and “Zacubo” from Onconic Therapeutics Inc. According to the pharmaceutical market research firm Ubiest, the 2025 outpatient prescription sales for P-CAB drugs in Korea reached 368.6 billion won, a 29% increase from the previous year.

An official from DaewonPharmaceutical stated, “Through this Phase 3 clinical trial, we have confirmed key results regarding the efficacy and safety of padoprazan,” adding, “We will strive to proceed smoothly with detailed analysis and the marketing authorization process so that we can provide a new treatment option for patients with gastroesophageal reflux disease.”

Meanwhile, padoprazan is a new P-CAB class drug candidate that inhibits gastric acid secretion by competitively binding to the proton pump—which is involved in gastric acid secretion—with potassium ions. The company received approval from the Ministry of Food and Drug Safety (MFDS) for its Phase 3 clinical trial plan in October of last year, enrolled its first patient in November of the same year, and completed the clinical trial in September of this year.