(001) A Comparison of Obinutuzumab Plus Venetoclax Sequencing on Tumor Lysis and Associated Outcomes in Patients with Chronic Lymphocytic Leukemia

Poster Abstract:

Background: Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) is the most common form of leukemia in the Western world, characterized by progressive proliferation of dysfunctional mature B-lymphocytes in the blood, lymph nodes and spleen. While the current National Comprehensive Cancer Network (NCCN) guidelines list multiple treatment options, one common approach is a regimen containing the combination of venetoclax and an anti-CD20 agent, such as rituximab or obinutuzumab. Initially, per the MURANO trial, venetoclax was administered prior to rituximab. In contrast, the CLL14 study administered obinutuzumab followed by a 5-week venetoclax ramp up. Grade ≥3 tumor lysis syndrome (TLS) occurred in 3% versus 2% of patients when venetoclax was administered pre- versus post-anti-CD20 agent, respectively. Based on prescribing patterns at Roswell Park Comprehensive Cancer Center (RPCCC), venetoclax is often given prior to obinutuzumab. Due to the potential risk of TLS associated with this sequence, hospital admission may be required to monitor and manage this risk effectively.


Objective: The primary aim of this study was to compare the frequency of clinical and laboratory TLS in CLL patients who received the sequence of obinutuzumab-venetoclax (OV) versus venetoclax-obinutuzumab (VO).


Methods: This is a retrospective chart review study that included adult CLL patients at RPCCC treated with obinutuzumab and venetoclax from January 2021 to November 2023. Patients were excluded if they received obinutuzumab with an agent other than venetoclax, discontinued therapy due to intolerance, or were lost to follow-up. Labs were collected at baseline and 24-hour post-venetoclax administration, which included lactate dehydrogenase (LDH), potassium, serum creatinine, corrected calcium, phosphate, uric acid, white blood cell count, and absolute lymphocyte count (ALC). Hospital length of stay, number of re-admissions within 7 days of initial discharge, death during initial admission, obinutuzumab hypersensitivity reactions and use of rasburicase were collected. Additionally, pharmacoeconomic analysis was conducted to compare cost between the two groups. Chi-square or Fisher’s exact tests were utilized to evaluate dichotomous variables. Continuous variables were analyzed via student’s t-test or Mann-Whitney U test.


Results: Results pending.

Conclusions: Conclusions pending.

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