Conference Coverage

DDW: Novel acid blocker holds its own against PPIs


AT DDW® 2015


WASHINGTON – An experimental acid suppressant was effective for prevention of peptic ulcer recurrence during NSAID therapy, with a safety profile similar to that of a currently marketed proton pump inhibitor, investigators reported.

At 2 years of follow-up, rates of recurrent peptic ulcers or hemorrhagic lesions in the stomach or duodenum among patients who took vonoprazan (marketed in Japan as Takecab) at a 10-mg or 20-mg daily oral dose were numerically but not statistically significantly lower than those for patients who took a 15-mg once daily dose of lansoprazole (Prevacid), said Dr. Yuji Mizokami of University of Tsukuba Hospital in Ibaraki, Japan.

Dr. Yuzi Mizokami

Dr. Yuzi Mizokami

“The long-term safety profile of vonoprazan was similar to lansoprazole, and no safety issues were identified,” he said at the annual Digestive Disease Week.

Proton pump inhibitors (PPIs) such as lansoprazole are frequently prescribed as concomitant gastroprotective agents in patients on long-term therapy with a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin or ibuprofen.

PIs have relatively short half-lives, however, which may limit their effectiveness as gastroprotectives. In addition, polymorphisms in the gene encoding for cytochrome P2C19 (CYP2C19) can affect PPI metabolism, Dr. Mizokami said.

Vonoprazan belongs to a new class of acid-suppressing drugs called potassium-competitive acid blockers (PCABs), which, unlike PPIs, do not need to be activated by acid to become effective and are not affected by genetic variations. Vonoprazan migrates from blood into the secretory canaliculus of acid-secreting parietal cells, and because of its longer elimination half-life and stability in acidic environments, provides a strong acid-inhibiting effect from the first dose, and remains effective for 24 hours, Dr. Mizokami explained.

He presented data from a 2-year extension of a phase III, 24-week noninferiority study comparing vonoprazan with lansoprazole for prevention of peptic ulcer recurrence. In that study, 5.5% of patients on lansoprazole had recurrent gastric or duodenal ulcers by week 24, compared with 3.3% of patients on 10 mg vonoprazan, and 3.4% of those on 20 mg vonoprazan.

A total of 357 patients completed the extension study: 108 initially assigned to lansoprazole, 131 to vonoprazan 10 mg, and 118 to vonoprazan 20 mg.

At 1 year, the rates of recurrent ulcers were 7% for patients on lansoprazole, 3.6% for those on vonoprazan 10 mg, and 5.4% for those on vonoprazan 20 mg. The respective rates at 2 years were 7.5%. 3.8%, and 5.9%. In a safety analysis (intention-to-treat), treatment-emergent adverse events were mild, did not appear to be dose dependent with vonoprazan, and did not increase over time.

Serious treatment-emergent events occurred in 8.6% among the patients on lansoprazole, 8.3% among patients on 10 mg vonoprazan, and 14.2% among those on 20 mg. Events leading to drug discontinuation occurred in 7.6%, 4.1%, and 12.2% of patients, respectively.

In all three study arms, but especially in the vonoprazan arms, there was an increase in serum gastrin seen at week 4, which increased moderately until week 52. After that, it began to decline among patients on vonoprazan, while plateauing among patients on lansoprazole.

There were also increases in pepsinogen I and II at week 4 in all three treatment groups; the levels remained stable thereafter, as did the ratio of pepsinogen I to pepsinogen II.

Vonoprazan is currently approved only in Japan. The manufacturer, Takeda, has not said if or when it intends to file for a New Drug Application in the United States. The study was supported by Takeda Pharmaceuticals. Dr. Mizokami disclosed serving as a consultant on the study. Four of the coauthors are company employees.

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