Diabetic Ketoacidosis During Lorlatinib Treatment: Case Report

Although hyperlipidemia is a well-known adverse event associated with lorlatinib treatment, lorlatinib-associated hyperglycemia is less common but can be potentially life-threatening. We present the case of a 65-year-old male patient with anaplastic lymphoma kinase–positive lung cancer and preexisting type 2 diabetes mellitus who developed diabetic ketoacidosis (DKA) after switching from alectinib to lorlatinib. After initiating lorlatinib treatment, the patient’s glycemic control deteriorated rapidly, with the glycated hemoglobin levels increasing from 6% to 11.5% within three months. The patient was admitted and received intensive insulin therapy along with temporary discontinuation of lorlatinib, which successfully resolved DKA. After a 2-week interruption, lorlatinib was resumed at a reduced dose with satisfactory glycemic control. This case highlights the importance of vigilant glucose monitoring for patients receiving lorlatinib, especially those with preexisting diabetes, to prevent life-threatening complications such as DKA.