Cemiplimab-Induced Hyperosmolar Hyperglycemic State With Concurrent Diabetic Ketoacidosis in a Patient Receiving Treatment for Cutaneous Squamous Cell Carcinoma

Abstract

The immune checkpoint inhibitor (ICI) cemiplimab is a human monoclonal antibody used in the treatment of locally advanced and metastatic cutaneous squamous cell carcinoma (CSCC) not amenable to surgery or radiation therapy. Although cemiplimab shows excellent efficacy with a good tolerability profile, it can cause side effects, including potentially life-threatening endocrinopathies. We discuss the case of a 77-year-old Caucasian female with CSCC treated with only three cycles of cemiplimab who presented with altered mental status and was found to have severe hyperglycemia, hyperosmolarity, ketonemia, glucosuria, and ketonuria concerning for hyperosmolar hyperglycemic syndrome (HHS) with concurrent diabetic ketoacidosis (DKA). The patient made a rapid recovery in the hospital while on standard therapies for HHS/DKA and cemiplimab was discontinued upon discharge. While there have been reports of cemiplimab-induced DKA, to our knowledge, this is the first reported case of cemiplimab-induced HHS-DKA. This report aims to shed light on cemiplimab-induced HHS-DKA and to underscore the need to elucidate the molecular mechanisms underlying ICI-induced diabetes mellitus (ICI-DM).