This trial is designed to evaluate the effect of glucagon receptor antagonism by volagidemab (once weekly) on glucose recovery from hypoglycemia after treatment with glucagon in adults with type 1 diabetes. After informed consent, Screening procedures to establish subject eligibility will be performed within a period of 28 days. Approximately 24 subjects with type 1 diabetes mellitus (T1DM) on stable doses of insulin will be enrolled.

After enrollment, subjects will undergo a baseline Hypoglycemia Recovery Procedure (with glucagon rescue). Subjects will then receive volagidemab subcutaneously (SC) once weekly for 6 weeks. At the end of the treatment phase, subjects will undergo a second Hypoglycemia Recovery Procedure. Subjects will be followed for 6 weeks after the last volagidemab dose with a final End-of-Study (EOS) visit during Week 12. The primary outcome will be the change in time to glucagon treatment success at Week 6 versus baseline.

Inclusion Criteria:

• Receiving insulin for the treatment of documented diagnosis of T1DM for at least 2 years
• Body Mass Index (BMI) of 18.5 kg/m2 to 35.0 kg/m2
• On treatment with a stable insulin regimen for at least 8 weeks
• Currently using a continuous glucose monitoring (CGM) system
• HbA1c less than or equal to 10.0%
• Females of non-childbearing potential must be ≥1 year post-menopausal or documented as being surgically sterile. Females of childbearing potential must agree to use two methods of contraception during the entire study and for an additional 3 months after the end of dosing with the investigational product
• Male subjects must be willing to use clinically acceptable method of contraception during the entire study and for an additional 3 months after the end of the treatment period
• Other inclusion criteria may apply.

Exclusion Criteria:

• History of type 2 diabetes, maturity onset diabetes of the young (MODY), pancreatic surgery or chronic pancreatitis
• Pancreas, pancreatic islet cells, or renal transplant recipient
• T1DM treatment with any other antihyperglycemic drug (e.g., metformin, alpha- glucosidase inhibitors, SGLT-2 inhibitors, pramlintide, inhaled insulin, pre-mixed insulins, etc.) within 30 days of Day 1
• Occurrence of severe hypoglycemia involving coma and/or seizure that required hospitalization or hypoglycemia-related treatment by an emergency physician or paramedic within 3 months prior to Day 1
• Myocardial infarction, unstable angina, revascularization procedure, or cerebrovascular accident ≤12 weeks
• Indication of liver disease
• Current signs and symptoms of anemia
• Untreated eating disorders such as bulimia or anorexia nervosa
• History of pancreatitis, pancreatic neuroendocrine tumors or multiple endocrine neoplasia (MEN) or family history of MEN.
• Treatment with systemic corticosteroids within 30 days of Day 1, or planned initiation of such therapy during the study.
• Medical history of cancer or treatment for cancer in the last five years
• Women who are pregnant, nursing, or who plan to become pregnant while in the trial
• Other exclusion criteria may apply