One of the main challenges in maintaining tight glucose control in a closed-loop system occurs at meal times. Amylin is a gluco-regulatory beta-cell hormone that is co-secreted with insulin in response to nutrient stimuli, and is deficient in patients with type 1 diabetes. Amylin, in the postprandial period, contributes to regulating glucose levels by delaying gastric emptying, suppressing nutrient-stimulated glucagon secretion, and increasing satiety. Pramlintide is a synthetic analog of the hormone amylin. A closed-loop system that delivers both insulin and pramlintide, based on glucose sensor readings, has the potential to better normalize glucose levels, especially during the post-prandial period.

The aim of this project is to assess whether co-administration of pramlintide with the improved insulin aspart formulation - Fiasp, in an artificial pancreas system, will alleviate the need for carb counting by replacing it with a simple meal announcement, without degrading the quality of glycemic control in a closed-loop therapy.

Inclusion Criteria:

1. Signed and dated written informed consent
2. Males and females ≥ 12 years of age
3. HbA1c ≤ 12%
4. Insulin pump use for at least 3 months
5. Clinical diagnosis with type 1 diabetes for at least 12 months. The diagnosis of T1D is based on the investigator's clinical judgment; C peptide level and antibody determinations are not planned.
6. Women of child-bearing potential must be ready and able to use a highly effective method of birth control. Women of childbearing potential are females who have experienced [the first occurrence of menstruation] and do not meet the criteria for women not of childbearing potential. Women not of childbearing potential are females who are permanently sterile or postmenopausal. Postmenopausal is defined as 12 consecutive months with no menses without an alternative medical cause.

Exclusion Criteria:

Participants who meet any of the following criteria are not eligible for the study:

1. Current or ≤ 1 month use of other antihyperglycemic agents (SGLT2 inhibitors, GLP-1 agonists, Metformin, Acarbose, etc.…).
2. Current use of glucocorticoid medication.
3. Use of medication that alters gastrointestinal motility.
4. Planned or ongoing pregnancy.
5. Breastfeeding individuals.
6. Severe hypoglycemic episode within one month of admission.
7. Severe diabetes ketoacidosis episode within one month of admission.
8. Clinically significant nephropathy, neuropathy or retinopathy as judged by the investigator.
9. Recent (< 6 months) acute macrovascular event e.g. acute coronary syndrome or cardiac surgery.
10. Known hypersensitivity to any of the study drugs or their excipients.
11. Individuals with confirmed gastroparesis.
12. Other serious medical illness likely to interfere with study participation or with the ability to complete the trial by the judgment of the investigator.
13. Unable to travel to research center within 3h if needed during study interventions
14. Failure to comply with team's recommendations (e.g. not willing to eat meals/snacks, not willing to change pump parameters, etc.).

Study Discontinuation/Withdrawal

1. Failure to comply with the protocol.
2. Pregnancy.
3. After an event which the PI believes it is not in the best interest for the patient to continue the trial.

The raw data (i.e., insulin delivery, glucose levels, individual participant data) and informed consent form could be shared by the corresponding author, ahmad.haidar@mcgill.ca, upon reasonable request for academic purposes, subject to Material Transfer Agreement and approval of McGill University Health Center's Research Ethics Board. All data shared will be deidentified. Study protocol is available with publication.

This study will be a double-blinded study, where the participants and researchers will be blinded to the study drugs. Participants will wear two pumps for all interventions, one for insulin and the other for pramlintide/placebo (saline solution).