Reassessment of the Risk of Hemolytic Syndrome in Patients With Chronic Lymphocytic Leukemia Treated With a Regimen Containing Venetoclax

Chronic lymphocytic leukemia is a malignant blood disorder characterized by the proliferation of abnormal B lymphocytes in the blood, lymph nodes, and bone marrow. It generally occurs after age 70 and is the fourth most common blood cancer in France, following multiple myeloma, diffuse large B-cell lymphoma, and myelodysplastic syndromes.

Treatments have advanced since 2015 with the introduction of immunotherapy and targeted therapies. The BCL2 inhibitor (venetoclax) is one of these innovative treatments. It is recommended as first-line therapy and for relapse in combination with anti-CD20 monoclonal antibodies and Bruton's tyrosine kinase inhibitors. Early studies showed that initial administration of venetoclax as monotherapy could lead to lysis syndrome as early as the first few days of treatment. This risk was correlated with the venetoclax dose and tumor burden. Prevention guidelines were subsequently proposed to guide management. This risk is therefore assessed before treatment begins (low, moderate, high), based on lymph node size and circulating lymphocyte count.

For patients at moderate and high risk, a treatment strategy is recommended that includes hyperhydration and uric acid-lowering agents, which may require hospitalization in some cases. The introduction of combination therapies has improved the depth and duration of response (obinutuzumab + venetoclax and ibrutinib + venetoclax). Venetoclax is added after the initiation of partner agents (22 days after obinutuzumab and 3 cycles after ibrutinib). This initial phase of treatment may reduce the risk of hemolytic syndrome. We propose here to reassess the risk of hemolytic syndrome before starting venetoclax in order to simplify management.