This study is designed to evaluate the safety, tolerability, pharmacokinetics (PK), and efficacy of HM15136 when used as add-on therapy in subjects with CHI with persistent hypoglycemia while on standard of care treatment (SoC). HM15136 will be administered once weekly in multiple doses to subjects in multiple age including pediatric to find appropriate exposure-response data.

Inclusion Criteria:

• Male and female subjects aged ≥2 years with CHI with persistent hypoglycemia despite current SoC treatment according to the investigator's evaluation or documentation
• Stable therapy with SoC medications with or without nutritional supplementation
• Previously undergone near-total pancreatectomy or being treated with a nonsurgical approach, having been evaluated as not eligible for pancreatic surgery
• HbA1c <7%

Exclusion Criteria:

• Subjects with type 1 or type 2 diabetes mellitus
• Other reasons for hypoglycemia, including but not limited to drug-induced hyperinsulinemic hypoglycemia, etc
• Treatment of CHI with continuous intravenous glucose or glucagon infusion within 3 months prior to screening
• Subjects with current use of any drugs that are known to interfere with the study drug, glucose metabolism, or study procedures (eg, use of systemic glucocorticoids [excluding topical, intra-articular or ophthalmic application, nasal spray, or inhaled forms] or insulin)
• Have conditions that could affect glucose levels such as pheochromocytoma, insulinoma, and glucagonoma