A phase I trial evaluating the safety and biological activity of iboctadekin (rhIL-18) in combination with rituximab in patients with CD20+ B-cell non-Hodgkin's lymphoma

8566 Background: Iboctadekin (rhIL-18) is an immunostimulatory cytokine that has demonstrated anti-tumor activity in several preclinical models. When administered as monotherapy in phase I clinical studies, rhIL-18 was safe, well tolerated and induced potent biological responses (e.g. Th1 cytokine production and expression of activation markers on NK, CD8+ and CD4+ cells). These data affirm the endogenous role of IL-18 as a co-stimulatory cytokine and suggest that its optimal use would be in a combination with other immune modulators such as rituximab. Methods: Patients with CD20+ B cell non-Hodgkin's lymphoma are being given rituximab (375 mg/m2) IV weekly for 4 consecutive weeks in combination with ascending doses of intravenous rhIL-18 (1 to 100 mcg/kg in 6 cohorts of 3 patients each) IV weekly for 12 weeks to identify a dose that is safe and tolerable and gives a maximum biological effect. Eligible patients must have disease which progressed after standard therapy or for which there is no effective st...