Evaluation of the Impact of Monitoring for Tumor Lysis During Venetoclax Ramp-Up in Chronic Lymphocytic Leukemia in Routine Clinical Practice.

Purpose: Venetoclax has made a significant impact in the treatment of chronic lymphocytic leukemia (CLL) due to its ability to induce deep and durable remissions with a finite duration of oral therapy. However, it can lead to tumor lysis syndrome (TLS) which is mitigated with dose escalation strategies. Patients who initiate venetoclax need to follow rigorous, and potentially burdensome, TLS monitoring during dose ramp-up. The frequency with which this rigorous monitoring leads to therapeutic interventions in clinical practice has not been well described. We conducted a study to assess the incidence of TLS and interventions needed after initiation of venetoclax in patients with CLL.

Methods: Adult patients with CLL who started treatment with venetoclax between July 2017 and March 2021 at Levine Cancer Institute were included in this study. Adherence to the venetoclax package insert (PI) for tumor lysis monitoring, incidence of laboratory as well as clinical TLS, and interventions resulting from the monitoring of TLS were collected.

Results: We report outcomes on 73 consecutive patients with CLL who initiated venetoclax. The majority of patients had low (49%) or medium (44%) tumor burden. During venetoclax ramp-up, 66% of patients adhered strictly to TLS monitoring as per the venetoclax PI. One patient developed laboratory TLS, and no patients developed clinical TLS. Six patients received unplanned interventions to treat TLS; all had medium or high tumor burden. There were no unplanned interventions in patients with low tumor burden.

Conclusion: In patients with low and medium tumor burden CLL who start venetoclax, the incidence of TLS is very low, and interventions are uncommonly needed.