Safety and Effectiveness of an Investigational Agent (GM-611) in Patients With Diabetic Gastroparesis

Inclusion Criteria: Major Inclusion Criteria - Others Stipulated within the Protocol The study physician must assure you have/are: * Must be at least 18 years of age and have diabetes mellitus requiring insulin, which may be in addition to oral anti-diabetic agents. * At least a three month history of the symptoms of gastroparesis that may include: early satiety (feeling full soon after beginning a meal), persistent fullness (long after eating), abdominal distention or bloating, nausea and vomiting. - No evidence of mechanical gastric obstruction, or other gastric problems since the onset of gastroparesis symptoms. * You may be required to under go a Gastric Emptying Test (GET) procedure. * You must be willing and able to maintain a daily telephone diary and consent to participate in this study. Exclusion Criteria: Major Exclusion Criteria - Others Stipulated within the Protocol The study physician must assure you do not have/are not: * Prior history of gastric surgery, excluding reflux surgery. * Inability to withdraw from current prokinetic agents (e.g., metoclopramide, erythromycin, others) prior to, and during the study. * Unstable current medical or surgical condition, or a recent history of frequent hospitalizations. * A history of: HIV, recurring infection affecting the gastrointestinal track, cirrhosis, acute or chronic liver disease, active pancreatitis, cholecystitis, psychosis, severe depression, Parkinson's disease, myopathy, scleroderma, eating disorder, or organ transplant. * Evidence or history of QT-prolongation, or use of drugs that are, or may be associated with QT-prolongation are prohibited. * May not be pregnant, breast-feeding or not using approved methods of contraception. * An allergy or intolerance to macrolide antibiotics (e.g., erythromycin). * Use of any investigational drug within 30 days prior to screening.