Concurrent administration of rituximab and CHOP chemotherapeutic agents for outpatients with CD20-positive lymphoma.

R (rituximab)-CHOP (cyclophosphamide, adriamycin, vincristin, and prednisone) is given to outpatients with CD20-positive lymphoma as a standard treatment. However, this regimen requires long-term infusion because of the necessity for monitoring the infusion reaction (IR) during R administration. In this study, pharmacological changes in anti-tumor agents were examined after the joint use of R and CHOP, and the possibility of concurrent administration of R and CHOP for outpatients was discussed. After combining antitumor agents with R, the binding capacity of R to the CD20 peptide and molecular changes in anti-tumor agents were measured by ELISA and LC/MS/MS-based analysis. At the same time, a pilot study involving concurrent administration of R and CHOP to patients with diffuse large B-cell lymphoma (DLBCL) was carried out after the first course of R-CHOP. After combining with either adriamycin or cyclophosphamide, the binding capacity of R to the CD20 antigen was equivalent to controls, and no molecular changes in adriamycin and cyclophosphamide were detected after combination with R. Twenty-one cases of DLBCL were treated safely with concurrent administration of R and CHOP. Twenty patients achieved complete remission after a full course of R-CHOP. The results indicated that long-term medication might not be necessary for outpatients treated with R-CHOP.