An Open-Label Multiple Dose Study of RZ358 in Patients With Congenital Hyperinsulinism

Inclusion Criteria: * Male or female age 2-45 years old (except age 12-45 in US) with an established clinical diagnosis of congenital hyperinsulinism * Able to provide written informed consent or, as applicable, assent * Confirmed hypoglycemia as assessed by CGM, SMBG, and clinical evaluation, during Screening * Willingness to use contraception if of child-bearing potential Exclusion Criteria: * Out of range blood work for study entry * Body Mass index outside of study entry criteria * History of malignancy * Clinically significant diseases, seropositivity for HIV, hepatitis B or C antibody * Use of systemic corticosteroids within 30 days before Screening * Known or suspected allergy to the study drug * Recent use of an investigational drug or treatment, or participation in an investigational study * Pregnant or lactating women * History of drug abuse or excessive alcohol use