Objective: To evaluate the time to discontinuation (TTD) and baseline characteristics among patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) treated with first-line (1L) venetoclax + obinutuzumab (VO) in the United States.
Methods: A nationwide electronic health record-derived database was used to select adults with CLL/SLL initiating a 1L venetoclax-based regimen between April 11, 2016-July 31, 2020. Study measures included TTD (defined as >120-day treatment gap or switching therapy) and baseline characteristics by discontinuation status.
Results: A total of 113 patients receiving 1L VO on/before July 31, 2020 were eligible for analysis (mean age: 65.9 years; 31.9% women). During the first 60 days post-treatment initiation, 3.5% had tumor lysis syndrome (TLS). The proportion of patients using corticosteroids, anti-hyperuricemics, and anti-emetics was higher during the first 60 days post-treatment initiation (100.0%, 78.8%, and 52.2%, respectively) than the period from day 61 onward (67.0%, 45.5%, and 33.9%, respectively). Mean (median) duration of active treatment was 11.6 (12.1) months; 16.8% discontinued treatment before completing 12 cycles, 68.1% completed ≥12 cycles (among which 29.9% completed ≥15 cycles), and 15.0% who did not discontinue treatment were censored before completing 12 cycles. Kaplan-Meier analysis showed that median TTD was 13.8 months. Relative to those completing ≥12 cycles, patients discontinuing treatment before completing the prescribed 12 cycles were older (70.4 vs. 65.1 years) and had poorer renal function (36.8% vs. 13.0% with creatinine clearance <60 mL/min).
Conclusion: A small proportion of CLL/SLL patients who were older and had poorer baseline renal function discontinued 1L VO prior to completing 12 treatment cycles. Additionally, treatment utilization, including medications related to TLS mitigation and management, was more intense during the initiation phase of VO. Further research with longer follow-up to assess long-term outcomes of VO treatment after early discontinuation is warranted.
Keywords: Venetoclax; chronic lymphocytic leukemia; obinituzumab; retrospective study; time to discontinuation; tumor lysis syndrome.