Insulin Lispro 6 Days Versus Insulin Aspart 6 Days in Pump Use

Patients will continue to use their current insulin pump for this study. Patients will receive insulin lispro and insulin aspart during this study. One medication will be taken for 12 weeks and then the other medication for 12 weeks. Neither the patient nor the study doctor will know which medication is being taken at any time. The order in which the two medications are taken will be determined by chance.


Eligibility Criteria:
Inclusion Criteria:

* Diagnosed with type 1 diabetes (World Health Organization criteria) for at least 24 months
* Treated with continuous subcutaneous insulin infusion (CSII) therapy for the previous 6 months
* Mean total daily insulin dose for 3 days prior to screening less than or equal to 46 units/day if using a 300-Unit reservoir, less than or equal to 30 units/day if using a 200 unit reservoir, or less than or equal to 26 units/day if using a 180 unit reservoir
* Baseline body mass index (BMI) less than or equal to 35.0 kilograms per meter squared (kg/m2)
* Baseline glycated hemoglobin A1c (HbA1c) 5% to 9%

Exclusion Criteria:

* Impaired renal function (serum creatinine greater than or equal to 2.0 milligrams per deciliter (mg/dL))
* Legal blindness
* Have had any episode in the 12 months prior to screening of hypoglycemic coma, seizures, or disorientation
* Have had hypoglycemia unawareness (routinely asymptomatic at blood glucose less than 45 mg/dL \[2.5 millimoles per liter (mmol/L)\]) in the 12 months prior to screening.
* Have had any emergency room visits or hospitalizations due to poor glucose control in the 12 months prior to screening.
* Have had a pump-related infusion site abscess in the 12 months prior to screening.
* Have had multiple, clinically significant occlusions as judged by the investigator.
* Have had any infection with Staphylococcus aureus in the past 5 years
* Have one of the following concomitant diseases: presence of clinically significant hematologic, oncologic, renal, cardiac, hepatic, or gastrointestinal disease, or any other serious disease considered by the investigator to be exclusionary.
* Participants with malignancy other than basal cell or squamous cell skin cancer who have not yet been treated, are currently being treated, or who were diagnosed less than 5 years ago.
* Have had a blood transfusion or severe blood loss within the 3 months prior to screening or have known hemoglobinopathy, hemolytic or sickle cell anemia, or any other traits of hemoglobin abnormalities known to interfere with HbA1c methodology.
* Are receiving chronic systemic glucocorticoid therapy, or have received such therapy within the 4 weeks preceding screening.
* Have an irregular sleep/wake cycle in the investigator's opinion.
* Have a known hypersensitivity or allergy to any of the study insulins or their excipients
* Are breastfeeding or pregnant, or intend to become pregnant during the course of the study, or are sexually active women of childbearing potential not actively practicing birth control by a method determined by the investigator to be medically acceptable.
* Are currently enrolled in, or discontinued within the last 30 days from a clinical trial involving off-label use of an investigational drug or device, or currently enrolled in any other type of medical research not to be scientifically or medically compatible with this study.
* Are unwilling or unable to comply with the use of a data collection device to directly record data from the participant.