What happened, in summary

A 76-year-old man with no history of diabetes developed shortness of breath in June 2015. A chest scan showed a large right-sided pleural effusion and several nodules in the upper and lower right lung. Fluid removed from the chest contained metastatic cancer cells. One month later, he underwent minimally invasive chest surgery with a right-upper-lobe wedge biopsy and talc pleurodesis to control the recurring fluid. The biopsy confirmed lung adenocarcinoma. Testing did not identify alterations in EGFR, ALK, ROS1 or KRAS.

Two months after presentation, he entered a clinical trial using 21-day treatment cycles. On day 1 he received pembrolizumab, carboplatin and nab-paclitaxel, followed by additional nab-paclitaxel on days 8 and 15. When he returned for cycle 2, day 8, his blood glucose was 616 mg/dL. He had no excessive thirst or urination and was not in diabetic ketoacidosis, but testing showed very low insulin production and positive anti-GAD and anti-IA2 antibodies, supporting new autoimmune type 1 diabetes.

He began long-acting and mealtime insulin. A trial of prednisone 10 mg daily was started 21 days after the high glucose was found and stopped after 25 days because it did not improve his insulin needs.

He completed 4 combination cycles. Treatment was briefly delayed for hyperglycemia and at 3 other points for low blood counts, but the right-lung nodules shrank and nearly resolved. He continued maintenance pembrolizumab every 3 weeks. His diabetes persisted, although insulin requirements and fasting glucose became stable.