Inclusion Criteria:

• 18 to 80 years of age, inclusive.
• Type 1 or type 2 diabetes mellitus.
• Female patients of childbearing potential must have a negative serum pregnancy test and use (and agree to continue to use throughout the study) an acceptable method of contraception.
• HbA1c level less than/equal to 10.0 % at the Screening Visit.
• Diagnosis of gastroparesis including (all three of the following requirements apply): i. Documented delayed gastric emptying; ii. A greater than 3 month history of symptoms of gastroparesis; iii. A GCSI Total Score greater than/equal to 2.66 at the Screening Visit and greater than/equal to 1.90 at the Day 1 visit.
• Upper gastrointestinal obstruction ruled out by endoscopy or barium scan.
• Concomitant medications must be stable for at least 2 weeks leading up to the Baseline Visit and be maintained during the study.
• Body Mass Index (BMI) < 35.
• Delayed gastric emptying by breath test demonstrated at the Baseline Visit.

Exclusion Criteria:

• Persistent daily vomiting
• Gastrectomy, obesity surgery, fundoplication, or vagotomy/pyloropasty.
• Pyloric Botox within 6 months prior to Screening Visit.
• NG, PEG or PEJ feeding tube.
• Required in-patient hospitalization for treatment of gastroparesis within 2 weeks prior to the Screening Visit.
• Parenteral nutrition for treatment of gastroparesis within 2 months prior to the Screening Visit.
• Active gastric pacemaker within 3 months prior to the Screening Visit.
• Participation in an investigational study within 30 days prior to study entry.
• Chronic severe diarrhea.
• Diabetic ketoacidosis requiring hospitalization within 30 days prior to study entry.
• History of any eating disorder within 2 years prior to study entry.
• Significant chronic obstructive pulmonary disease or chronic asthma.
• Patient is a heavy smoker, and/or unable or unwilling to abstain from smoking during each of the three study visits during which the gastric emptying breath tests will be performed.
• History of risk factors for Torsades de Pointes.
• Patient requires treatment with certain concomitant medications known to have a clinically recognized risk for Torsades de Pointes.
• History of acute myocardial infarction (MI) or unstable angina within 12 months prior to study entry.
• History of any psychiatric disorder or cognitive impairment that would interfere with participation in the study.
• History of alcohol dependency within 2 years prior to study entry.
• Taking opiates for abdominal pain.
• History of HIV infection.
• History of Hepatitis B or C currently exhibiting symptoms expected to worsen during course of study.
• Requires dialysis or has severely impaired renal function.
• Severe impairment of liver function.
• Uncontrolled hypo- or hyperthyroidism.
• History of adrenal insufficiency.
• Pregnant or is breast-feeding.
• Allergic to or intolerant of wheat, egg, soy or milk products.
• Patient requires a gluten-free diet.
• Any other medical condition or social circumstance that, in the investigator's opinion, makes it inappropriate for the patient to participate in this clinical trial.