Clinical activity and safety of combination immunotherapy with interferon-alpha 2a and rituximab in patients with relapsed low grade non-Hodgkin's lymphoma

Background and Objectives. To determine the clinical activity and safety of the combination immunotherapy of the chimeric anti-CD20 antibody, rituxima b, and interferon (IFN)-alpha 2a. Design and Methods. Sixty-four patients with relapsed low-grade or follicul ar B-cell non-Hodgkin's lymphoma received 4 infusions of rituximab (375 mg/ m(2) per infusion) after priming and simultaneous treatment with IFN-alpha 2a. Results. The overall response rate was 70% with 33% complete responses. The median duration of response is 19 months, after a median follow-up of 22 m onths. By univariate analysis none of the most common prognostic factors pr edicted for response to therapy. After treatment 10 patients became bcl-2 n egative in the bone marrow, but no correlation between molecular and clinic al response was found. Fifty-three patients (83%) had adverse events that w ere drug related or of unknown origin. The number of adverse events per pat ient varied from 1 to 21. Considering all 272 events, 231 (85%) were grade 1 or 2, 36 (13%) grade 3 and 5 (2%) grade 4. Twenty-three patients required a reduction in the dose and/or short discontinuation of IFN treatment, eit her during priming or subsequent treatment. The most frequent adverse event s were leukopenia, fever, neutropenia, hypotension and thrombocytopenia. Interpretation and Conclusions. This report shows that combination immunoth erapy (rituximab + IFN-alpha 2a) is active and relatively well tolerated. T he overall response rate of 70% and the median duration of remission of 19 months compare favorably with the results obtained with rituximab alone in a similar subset of patients. Randomized trials investigating rituximab ver sus combination immunotherapy are needed. (C) 2001, Ferrata Storti Foundati on.