This is an open-label, exploratory pilot study in patients with T1D. The study will involve two daytime clinical research center visits 7-14 days apart. Subjects will receive a single injection of G-Pen™ (glucagon injection) at each visit.

Following eligibility confirmation, each study participant will undergo two episodes of insulin-induced hypoglycemia with plasma glucose < 50 mg/dL. Both episodes will be treated with a single subcutaneous injection of G-Pen™ glucagon. For the first treatment visit, all subjects will receive a 1 mg dose of G-Pen™ glucagon. The investigator will have discretion to repeat this same dose at the second treatment visit or give a 0.5 mg dose of G-Pen™ glucagon. A follow-up phone call will be conducted 3-7 days following administration of the final dose of study drug as a safety check.

Inclusion Criteria:

• Type 1 diabetes mellitus for at least 24 months

Exclusion Criteria:

• Pregnant or Lactating
• HbA1c >10.5% at screening
• Use of > 2.0 U/kg total insulin dose per day
• Inadequate bilateral venous access in both arms
• Renal insufficiency
• Congestive heart failure, NYHA class II, III or IV
• Active malignancy within 5 years from screening
• Major surgical operation within 30 days prior to screening
• Seizure or bleeding disorder
• Glycogen storage disease
• Active substance or alchohol abuse

All enrolled subjects

Total evaluation time was up to 3 weeks per subject.

Treatment-emergent events observed during the dosing visits or subsequently reported by the subjects between visits or at the follow-up phone call occurring 3-7 days after the second treatment visit were recorded.