U.S. Department of Health and Human Services，Food and Drug Administration，Center for Drug Evaluation and Research (CDER) issued Guidance for Industry Helicobacter pylori-Associated Duodenal Ulcer Disease in Adults: Developing Drugs for Treatment in October 2009. The purpose of this guidance is to assist sponsors in clinical drug development for the treatment of adults with duodenal ulcers caused by Helicobacter pylori (H. pylori) for the reduction of duodenal ulcer recurrence. This guidance recommended that H. pylori eradication at greater than 28 days from the end of therapy should be used as the primary endpoint for determining outcome in clinical trial design for drugs being developed to treat duodenal ulcers caused by H. pylori infection. This eradication endpoint was considered a valid (and validated) surrogate endpoint for duodenal ulcer recurrence, based on published studies demonstrating that H. pylori eradication in patients an active ulcer significantly reduced future ulcer recurrence. Therefore, clinical trials did not need to include evaluation of ulcer recurrence to be approved for active duodenal ulcer associated with H. pylori infection.