Patient description: The patient is a 24-year-old man who has had type 1 diabetes for 11 years. He presents to the emergency room with hyperglycemia and concern for possible diabetic ketoacidosis after not taking his insulin for 3 days. The patient reports that he is currently homeless and has lost his supply of insulin, syringes, glucometer, and glucose testing supplies. The patient states that at the time of his initial diagnosis with type 1 diabetes he was hospitalized with a glucose value >1000 mg/dL. At the time, he was experiencing polyuria, polydipsia, and polyphagia. He reports that he has been on insulin since the time of his diagnosis, and he has never been prescribed oral agents for diabetes management. Most recently, he has been using insulin glargine 55 units once daily, and insulin aspart sliding scale 3 times daily. The patient has had previous episodes of diabetic ketoacidosis, for which he was hospitalized. With this episode of hyperglycemia, he is not experiencing any nausea, vomiting, or abdominal discomfort, and he appears well. His lab studies showed: A1c: 11.3% Creatinine: 0.9 mg/dL with eGFR >60 mL/min Aspartate aminotransferase (AST): 17 U/L Alanine aminotransferase (ALT): 14 U/L Beta-hydroxybutyrate: 0.1 mmol/L Bicarbonate: 25 mEq/L Anion

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Type 1 Diabetes Clinical diagnosis, based on investigator assessment, of type 1 diabetes for at least one year and using insulin for at least 1 year Using an insulin pump for at least 3 months (which may use of automated features) Familiarity and use of a carbohydrate ratio for meal boluses Age ≥18.0 years old For females, not currently known to be pregnant. If female and sexually active, must agree to use a form of contraception to prevent pregnancy while a participant in the study. A negative serum or urine pregnancy test will be required for all females of child-bearing potential. Participants who become pregnant will be discontinued from the study. Also, participants who during the study develop and express the intention to become pregnant within the timespan of the study will be discontinued If using a personal CGM, willingness to use a Dexcom G6 CGM and discontinue personal CGM use during the study Willing not to begin use of, or not to continue use of if currently using, a personal AID (closed loop control) system during the study; note if the system offers an open-loop mode or can be switched to a PLGS mode that is compatible with the Dexcom G6, the system may be used during the study in these modes only Willingness to switch to lispro (Humalog) or aspart (Novolog) if not using already, and to use no other insulin besides lispro (Humalog) or aspart (Novolog) during the study Willingness not to start any new non-insulin glucose-lowering agent during the course of the trial, and not to use Afrezza during the trial Investigator believes that the participant can successfully and safely operate all study devices and is capable of adhering to the protocol  Use of Afrezza or any non-insulin glucose-lowering agent other than metformin (including GLP-1 agonists, DPP-4 inhibitors, SGLT-2 inhibitors, sulfonylureas) unless participant is willing to discontinue during the trial Two or more episodes of DKA requiring an emergency room visit or hospitalization in the past 6 months Two or more episodes of severe hypoglycemia with seizure or loss of consciousness in the last 6 months Hemophilia or any other bleeding disorder A medical or other condition that in the opinion of the investigator could create a safety concern for the participant or put the study at risk. History of frequent severe hypoglycemia or history of frequent severe hyperglycemia and/or ketosis, without emergency room visit or hospitalization, due to poor diabetes self-management may be disqualifying per investigator judgment Participation in another pharmaceutical or device trial at the time of enrollment or during the study