Anti‑PD1 therapy‑associated distal renal tubular acidosis: A case report.

Distal renal tubular acidosis (RTA) is a rare adverse reaction to immune checkpoint inhibitors, which only occurs in a small number of cases. To the best of our knowledge, distal RTA caused by sintilimab, a programmed cell death protein 1 (PD-1) inhibitor, has not been previously reported. In the present study, the case of a 62-year-old man with metastatic cardiac carcinoma treated with sintilimab anti-PD-1 therapy was reported. After the fourth administration of sintilimab, the treatment course was interrupted by metabolic hyperchloraemic acidosis with hypokalaemia. Following urine and blood tests, immunotherapy-induced distal RTA was suspected. Treatment with sintilimab and chemotherapy was stopped, and treatment with sodium bicarbonate and potassium citrate was started, which resulted in an adequate response. The present study provides the first case of distal RTA secondary to sintilimab treatment.