To assess the efficacy of 3 oral dosing regimens of ATI 7505 compared to placebo in patients with PDS by comparing at the end of Day 42 the percentage of patients in each treatment group who have had adequate relief of postprandial distress syndrome symptoms on at least 50% of the treatment days.

Inclusion Criteria:

• Were diagnosed with PDS at least 6 months prior to screening, OR had onset of 2 or more PDS symptoms at least 6 months prior to screening.
• Experienced early satiety or bothersome postprandial fullness repeatedly during the 3 months prior to screening.
• Had a normal upper GI endoscopy within the past year.

Exclusion Criteria:

• Heartburn that occurs >3 times per week
• Current Helicobacter pylori (H pylori) infection confirmed by stool sample testing or breath testing, or H pylori eradication therapy within the 6 months prior to screening
• Any alarm symptoms including uninvestigated anemia, rectal bleeding, weight loss, or unresolved fever within the 6 months prior to screening
• At screening, a QT interval corrected for heart rate using Bazett's correction formula (QTcB) >440 msec as determined by the Investigator.