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Kidney Week

Abstract: PO1870

Immune Checkpoint Inhibitors Associated Distal RTA with and Without AKI

Session Information

Category: Onco-Nephrology

  • 1500 Onco-Nephrology

Authors

  • Henderson, David, University of Florida College of Medicine, Gainesville, Florida, United States
  • Jhaveri, Kenar D., Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, United States
  • Wanchoo, Rimda, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, United States
  • Shah, Chintan Vimalkumar, University of Florida College of Medicine, Gainesville, Florida, United States
Introduction

As immune checkpoint inhibitors (ICPI) gain popularity as a widely used anti-cancer therapy, unique immune-related adverse events (irAE) are being associated with their use. Hereby, we present two cases that link ICPI therapy to distal RTA, one with and one without AKI.

Case Description

A 73-year-old male with urothelial cancer on pembrolizumab was evaluated for AKI and acidosis. After 5 doses of ICPI therapy, he was noted to have a serum creatinine of 1.8mg/dl (normal baseline) and a serum CO2 of 20mmol/L. Over the next few days, the serum C02 further decreased to 11mmol/L and serum potassium declined to 3.0mmol/L. Further workup revealed a urine pH of 6.5 with a positive urine anion gap. He was diagnosed with likely ICPI-induced AIN with distal RTA and initiated on sodium bicarbonate, potassium citrate, and prednisone 60mg/day. His ICPI was held. After 2 weeks of treatment, his serum creatinine returned to 1.2mg/dl and serum C02 to 22mmol/L.

A 46-year-old female was diagnosed with metastatic lung cancer and squamous cell cancer of the right tonsil for which she was initially treated with Carboplatin/Paclitaxol/Pembrolizumab followed by maintenance Pembrolizumab. Almost 3 months after being initiated on ICPI, she was noted to have normal gap metabolic acidosis that gradually worsened to serum CO2 of 15mmol/L along with serum potassium of 2.4meq/L and serum creatinine of 0.6 mg/dl. Further workup showed a urine anion gap of +26, urine osmolar gap of 80, urine pH of 6.0. 24-hour urine citrate was undetectable. Diagnosis of distal RTA secondary to pembrolizumab was made and therapy was held. Steroids were not initiated, as the kidney biopsy, performed within 2 months of holding the therapy, did not reveal any tubulitis or cellular infiltrates. She is being treated with potassium citrate with normalization of acidosis and hypokalemia.

Discussion

We describe two cases of distal RTA presenting as immune related adverse events associated with use of ICPI. AKI presence is not necessary. Prompt recognition and treatment can lead to quick recovery. It has been postulated that a difference in the expression of PD-L1 among the tubular epithelial cells is responsible for isolated distal RTA