Introduction
Chronic lymphocytic leukemia (CLL) is a chronic lymphoproliferative disorder characterized by progressive accumulation of functionally incompetent lymphocytes that are usually monoclonal in origin.1 Most patients will respond to initial therapy, but disease relapse invariably occurs and becomes refractory with each relapse. Venetoclax, which is an orally bioavailable, selective, small-molecule inhibitor of BCL2, is a new therapeutic agent for relapsed or refractory CLL.2 Concerning the toxicity of venetoclax, tumor lysis syndrome (TLS) has been reported as a severe adverse event due to venetoclax treatment and intensive prevention and strict monitoring are recommended according to the risk level of TLS defined by tumor burden and renal function for the use of venetoclax.3
Chronic kidney disease (CKD) refers to kidney damage or decreased kidney function for three or more months, regardless of the cause. Decreased kidney function is defined as a glomerular filtration rate (GFR) of less than 60 mL/min/1.73 m2, and severe CKD (stage 4) is defined as a GFR of less than 30 mL/min/1.73 m2.4 To the best of our knowledge, venetoclax use has not been reported in patients with severe CKD. Herein, we describe a case of relapsed CLL patient with severe CKD due to congenital solitary kidney that was successfully treated with venetoclax.