Potassium Acid Blocker No Better Than PPI for Artificial Gastric Ulcers

Vonoprazan, a potassium-competitive acid blocker, was not superior to the proton pump inhibitor (PPI) lansoprazole (Prevacid) for healing artificial gastric ulcers among patients with gastric tumors, Japanese researchers found in a randomized, open-label trial.

Following endoscopic submucosal dissection (ESD), the difference in artificial gastric ulcer healing rate at 1 month for patients receiving vonoprazan was not significantly different compared to patients receiving lansoprazole (20.0% vs 16.9%, respectively; P=0.60), reported Ryuta Takenaka, MD, of the Tsuyama Chuo Hospital in Tsuyama, Japan, and coauthors in BMC Gastroenterology.

Vonoprazan is used to treat Helicobacter pylori infections. This drug has been deemed longer acting, with a stronger potency than PPIs.

Lansoprazole is used to treat gastroesophageal reflux disease (GERD); it works by reducing stomach acid thereby preventing acid buildup, gastric ulcers, H. pylori infections, and also prevents heartburn.

Several previous studies reported similar findings for 1-month healing rates of vonoprazan — ranging between 7.4% to 20.9% and improved clinical benefits over PPIs. Another previous study linked vonoprazan with a reduced delayed bleeding rate in patients with an ESD-induced gastric ulcers, but on a small scale.

ESD is used for the early detection of gastric cancer. However, perforation and bleeding are potential complications of the procedure. PPIs are commonly used in treating ESD-induced gastric ulcers, but are not always successful in healing. Therefore, researchers sought out to find another potentially more effective therapeutic.

“Our hypothesis was that the strong and rapid inhibition of gastric acid secretion by vonoprazan may enhance the healing of artificial ulcers,” explained Takenaka and coauthors.

From April 2015 to December 2017, there were 168 patients enrolled in this study. The primary endpoint was the artificial gastric ulcer healing rate at 1 month post-ESD. Secondary endpoints included the artificial ulcer shrinkage rates at 1 and 2 months, the healing rate at 2 months, as well as potential complications (delayed perforation/post-operative bleeding).

A variety of patients with ESD were included in the trial, including those with differentiated mucosal cancers of any size with no ulcer, differentiated mucosal cancers with ulcer size less than or equal to 3 cm, or undifferentiated mucosal cancers less than/equal to 2 cm with no ulcer. Patients with neuroendocrine tumors (grade 1; less than/equal to 1 cm) only found within the layer of the submucosa, or with adenomas deemed “suspicious for mucosal cancer” were also included.

Patients excluded from this trial were those who developed an injury to their mucosal lining of the stomach after having been prescribed NSAIDs, steroids, and antithrombotic drugs, those who had drug allergies, those with complications during an ESD and those having a remnant stomach as a result of prior gastric surgery.

The protocol included initially giving all patients 30 mg of lansoprazole by IV twice on the day of having an ESD. The second day after surgery, patients were randomized into two groups to receive 20 mg of vonoprazan orally per day or 30 mg of lansoprazole orally per day. Follow-up with an esophagogastroduodenoscopy was done at 1-month and 2-month intervals, post-ESD.

Patient demographics, including H. pylori status, ESD ulcer index, and tumor location were all similar. In both groups, the average age of patients was 73, with 70%-74% being men, and 53%-66% with hypertension. The average lesion size was 1 cm and 63%-75% of patients had differentiated adenocarcinomas. In both groups, the average ESD index was 875 mm². About 35%-37% of patients tested positive for the anti-H. pylori antibody.

There was no significant difference between groups in artificial gastric ulcer healing rate at 2 months (77.6% for vonoprazan vs 84.3% for lansoprazole; P=0.27).

Moreover, median artificial gastric ulcer shrinkage rates at 1 month also showed no significant differences either (96.3% vs 95.1%, respectively; P=0.68). The median shrinkage rate for both groups at 2 months was 100%.

In the vonoprazan group, no patients experienced postoperative bleeding, though one patient experienced a delayed perforation that occurred after ESD by 2 days. Three patients experienced postoperative bleeding in the lansoprazole group.

Limitations to this trial included the small population studied and that all patients were studied from a single center in Japan. The trial also excluded patients taking antithrombotic drugs, so the rate of postoperative bleeding may be underrepresented here, since it is associated with antithrombotics.

Takenaka and coauthors stated that “the effect of vonoprazan remains controversial,” and that further randomized trials are warranted.