Clinical characterization of first cycle reactions in patients with chronic lymphocytic leukemia treated with oblimersen

Abstract

16514 Background: Serious adverse reactions during the first treatment cycle characterize many drugs used for chronic lymphocytic leukemia (CLL), including rituximab, alemtuzumab, flavopiridol, lenalidomide, and oblimersen. Termed cytokine release reactions (CRRs), these events have occurred more commonly in pts with bulky disease and elevated leukocyte counts, and some have been fatal. Rapid increases in serum levels of tumor necrosis factor-α, interleukin-6, interleukin-2, interferon-γ, and other cytokines may result in symptoms including fever, chills, nausea, vomiting, hypotension, and dyspnea. Ex vivo treatment of CLL cells with oblimersen induce release of vasoactive interleukin-8. First cycle reactions, including tumor lysis syndrome (TLS), proved dose-limiting in a phase 1–2 trial of oblimersen in pts with relapsed or refractory CLL. To characterize these reactions, we evaluated data from this single-agent study and from a phase 3 randomized clinical trial of oblimersen with fludarabine and cyclophosphamide (Flu/Cy). Methods: Data on investigator assessment of CRR and TLS were obtained from both studies, which included 155 pts; 40 were treated with oblimersen alone (3–7mg/kg/d by CIV for 5–7 days) and 115 with oblimersen (3 mg/kg/d × 7 days) in combination with Flu/Cy. Results: Of 145 pts treated with oblimersen 3mg/kg/d, either alone or with Flu/Cy, 2 pts (1.3%) experienced CRR and TLS, respectively. Two CRRs occurred in 10 pts treated with 4–7mg/kg/d. Reactions typically began 24–48 hours after starting treatment. CCR was usually associated with spiking fever, nausea, dehydration, rigors, and back pain. Rarely pts developed hypotension, acidosis, or reversible renal insufficiency, usually with a reduction in WBC. Symptoms lasted 1 day to several weeks (1 pt). In most cases, reactions were reversible with intensive supportive care, including IV fluids, pressors, and antibiotics; 1 death from TLS and 1 from CCR occurred during cycle 1. There was no definitive correlation with baseline measures of disease burden. Conclusion: First cycle oblimersen reactions are uncommon but represent a risk. Early symptoms (fever, nausea, and dehydration) require aggressive treatment, which may prevent progression of the reaction. [Table: see text]