Risk Factors for Tumor Lysis Syndrome in patients with Chronic Lymphocytic Leukemia Treated with the Cyclin Dependent Kinase Inhibitor, Flavopiridol

Tumor lysis syndrome (TLS) has been described in over 40% of patients with chronic lymphocytic leukemia (CLL) treated with the cyclin dependent kinase inhibitor, flavopiridol. We conducted a retrospective analysis to determine predictive factors for TLS. In 116 patients, the incidence of TLS was 46% (95% CI: 36%-55%). In univariable analysis, female gender, greater number of prior therapies, Rai stages III-IV, adenopathy ≥ 10 cm, splenomegaly, del(11q), decreased albumin, and increased absolute lymphocyte count, white blood cell count (WBC), β2-microglobulin, and lactate dehydrogenase (LDH) were associated (p<0.05) with TLS. In multivariable analysis, female gender, adenopathy ≥ 10 cm, elevated WBC, increased β2-microglobulin, and decreased albumin were associated with TLS (p<0.05). With respect to patient outcomes, 49% and 44% of patients with and without TLS, respectively, responded to flavopiridol (p=0.71). In a multivariable analysis controlling for number of prior therapies, cytogenetics, Rai stage, age, and gender, progression-free survival (PFS) was inferior in patients with TLS (p=0.01). Female patients and patients with elevated β2-microglobulin, increased WBC, adenopathy ≥ 10 cm, and decreased albumin were at highest risk and should be monitored for TLS with flavopiridol. TLS does not appear to be predictive of response or improved PFS in patients receiving flavopiridol.