Anti–Insulin Receptor Antibody for Malignant Insulinoma and Refractory Hypoglycemia

This correspondence reports the successful use of RZ358, a novel human anti insulin receptor monoclonal antibody, in a 55 year old man with metastatic insulinoma and refractory hypoglycemia unresponsive to conventional therapies, including octreotide, diazoxide, and everolimus. The patient experienced severe hypoglycemia (glucose levels as low as 20 mg/dL) despite maximal medical intervention. After obtaining emergency FDA authorization, RZ358 was administered, leading to significant attenuation of hypoglycemia and reduced dependence on dextrose infusions. The patient achieved metabolic stability after multiple RZ358 doses, enabling discontinuation of other therapies. This case highlights RZ358 as a promising treatment for malignant insulinoma-induced hypoglycemia, warranting further studies to establish dosing protocols and broader applications for metabolic disorders.

This correspondence reports the successful use of RZ358, a novel human anti insulin receptor monoclonal antibody, in a 55 year old man with metastatic insulinoma and refractory hypoglycemia unresponsive to conventional therapies, including octreotide, diazoxide, and everolimus. The patient experienced severe hypoglycemia (glucose levels as low as 20 mg/dL) despite maximal medical intervention. After obtaining emergency FDA authorization, RZ358 was administered, leading to significant attenuation of hypoglycemia and reduced dependence on dextrose infusions. The patient achieved metabolic stability after multiple RZ358 doses, enabling discontinuation of other therapies. This case highlights RZ358 as a promising treatment for malignant insulinoma-induced hypoglycemia, warranting further studies to establish dosing protocols and broader applications for metabolic disorders.