Iacona I, Lazzarino M, Avanzini M A, Rupolo M, Arcaini L, Astori C, Lunghi F, Orlandi E, Morra E, Zagonel V, Regazzi M B
Department of Pharmacology, University of Pavia, IRCCS Policlinico San Matteo, Italy.
Ther Drug Monit. 2000 Jun;22(3):295-301. doi: 10.1097/00007691-200006000-00010.
Rituximab is a chimeric monoclonal antibody (MAb) directed against the B-cell CD20 antigen that has been approved for therapy of relapsed and resistant follicular non-Hodgkin's lymphoma (NHL). This study describes the development and validation of a highly sensitive, rapid, accurate, precise enzyme-linked immunosorbent assay (ELISA) to measure Rituximab serum concentrations. This study also describes the application of the ELISA method to a pharmacokinetic study in a homogeneous group of patients with follicular lymphoma who received 4 weekly doses of MAb at the standard dose of 375 mg/m2 as consolidation of chemotherapy. In the patients in this study, the median Rituximab serum concentrations increased during therapy, and showed a slow decline during the posttreatment period. The Rituximab elimination half-life of approximately 20 days accounts for the demonstrated accumulation of MAb in serum samples. Because previous pharmacokinetic studies showed a correlation between Rituximab serum levels and tumor response, the ELISA method used in this study, which allows a precise control of serum concentrations, could be useful for predicting the final response to the MAb and for selecting patients able to benefit from higher dosage or repeated drug administration.
