Trial of IW-3718 for 8 Weeks in Patients With Persistent Gastroesophageal Reflux Disease (GERD) Receiving Proton Pump Inhibitors (PPIs)

Change From Baseline in Weekly Regurgitation Frequency Score (WRFS) at Week 8

The WRFS is defined as the average of available daily regurgitation frequency scores (DRFS) during a week. DRFS is defined as the maximum score of the 2 items measuring regurgitation from a particular day (Item #6 "Regurgitation \[liquid or food moving upwards toward your throat or mouth\]" and Item #7 "An acid or bitter taste in the mouth"). The DRFS items are assessed on a 4-point ordinal scale, where 0=Never, 1=Rarely, 2-Sometimes, 3=Often, and 4=Very Often; higher scores indicate worse symptoms. A negative change from baseline indicates improvement.

Time frame: Baseline, Week 8

Percentage of Participants Who Were Overall Heartburn Responders During the 8-Week Treatment Period

An overall heartburn responder is a participant who is a weekly heartburn responder for at least 4 of the 8 treatment weeks and for at least 1 of the final 2 treatment weeks (i.e., Week 7 and Week 8). A weekly heartburn responder is a participant with a decrease of \>/= 45% from baseline in WHSS. A participant who reported heartburn severity for less than 4 days during a week is not considered a responder for that week. The WHSS is defined as the weekly average of the DHSS. The DHSS for a day is the greater of the 2 items assessing heartburn severity (Item #1 "Burning feeling behind the breastbone or in the center of the upper stomach" and Item #2 "Pain behind the breastbone or in the center of the upper stomach"). The DHSS items are assessed on a 5-point ordinal scale, where 0=Did Not Have, 1=Very Mild, 2=Mild, 3=Moderate, 4=Moderately Severe, and 5=Severe; higher scores indicate worse symptoms. A negative change from baseline indicates improvement