Real-world incidence and prevention of tumor lysis syndrome in chronic lymphocytic leukemia treated with venetoclax

Abstract

Venetoclax is a BCL2 inhibitor used in chronic lymphocytic leukemia (CLL) which can cause tumor lysis syndrome (TLS). We aimed to determine the incidence of and risk factors for TLS among patients with CLL/small lymphocytic lymphoma (SLL) who received treatment with venetoclax at our institution from 1/1/2016 to 12/31/2020. We included 616 venetoclax escalations among 136 pts with CLL. 74 pts (54%) underwent escalation exclusively outpatient, 35 (26%) had at least one planned hospitalization and 27 (20%) were escalated exclusively inpatient. During venetoclax initiation, 86% of pts received allopurinol, 71% intravenous hydration, 18% phosphate binders, and 10% prophylactic rasburicase. Among the entire cohort, 7 pts (5.1%) developed laboratory TLS by modified Cairo Bishop criteria and none developed clinical TLS. Incidence of laboratory TLS was 15% for those escalated exclusively inpatient, 2.9% for those with any prophylactic hospitalization and 2.7% for those escalated exclusively outpatient. Those who developed TLS were more likely to have higher TLS risk, and no additional risk factors were identified. In this single institution retrospective cohort study, laboratory TLS was observed, though clinical TLS was not. Prophylactic measures, including use of IV hydration, may have contributed to low rates of observed TLS in the outpatient setting.