The objectives of this study are to evaluate the safety of IW-9179 in patients with diabetic gastroparesis (DGP) and the effect of treatment on the cardinal symptoms of DGP.

Inclusion Criteria:

• Patient is a male or non-pregnant, non-breastfeeding female, and is age 18 years or older at the time of the Screening Visit.
• Patient has a confirmed diagnosis of type 1 or type 2 diabetes mellitus.
• Patient has a diagnosis of DGP with no history or evidence of mechanical obstruction, symptoms for at least 3 consecutive months preceding the Screening Visit, and delayed gastric emptying of solids documented within 2 years of the Screening Visit.
• Patient has a normal EGD either during the Screening Period or within 2 years of the Screening Visit, with no evidence of structural or organic disease that may explain the patient's gastroduodenal symptoms.
• Patient is compliant with eDiary completion.
• Patient agrees to refrain from making any new, major lifestyle changes.
• Patient is fluent and literate in English.

Exclusion Criteria:

• Patient has a history or current symptoms of any organic or structural disease that, in the opinion of the investigator, can cause abdominal pain or discomfort and may confound the assessment of DGP symptoms.
• Patients with rumination syndrome, cyclic vomiting syndrome, anorexia nervosa, or bulimia.
• Patient is currently using a gastric electric stimulator or has had endoscopic pyloric injections of botulinum toxin within the 6 months prior to the Screening Visit.
• Patient has been hospitalized within the 2 months prior to the Screening Visit for uncontrolled diabetes mellitus, DGP, or associated malnutrition.
• Patient reports significant diarrhea during the four weeks prior to the Screening Visit, or more than 2 days during either week of the Pretreatment Period.
• Patient has had surgery of the GI tract any time before the Screening Visit, an appendectomy or cholecystectomy during the 3 months before the Screening Visit, non-GI surgery of the abdomen, pelvis, or retroperitoneal structures during the 6 months, or other major non-GI surgery during the 30 days before the Screening Visit.
• Patient has a history of cancer (resected basal cell or squamous cell carcinoma of the skin is acceptable).