Phase I study of chimeric anti-CD20 monoclonal antibody in Chinese patients with CD20-positive non-Hodgkin's lymphoma

Objective: This study was designed to determine the safety, pharmacokinetics and biologic effects of a human-mouse chimeric anti-CD20 monoclonal antibody (SCT400) in Chinese patients with CD20-positive B-cell non-Hodgkin's lymphoma (CD20+ B-cell NHL). SCT400 has an identical amino acid sequence as rituximab, with the exception of one amino acid in the CH1 domain of the heavy chain, which is common in Asians. Methods: Fifteen patients with CD20+ B-cell NHL received dose-escalating SCT400 infusions (250 mg/m2: n=3; 375 mg/m2: n=9; 500 mg/m2: n=3) once weekly for 4 consecutive weeks with a 24-week follow-up period. The data of all patients were collected for pharmacokinetics and pharmacodynamics analyses. Results: No dose-limiting toxicities were observed. Most drug-related adverse events were grade 1 or 2. Two patients had grade 3 or 4 neutropenia. Under premedication, the drug-related infusion reaction was mild. A rapid, profound and durable depletion of circulating B cells was observed in all dose groups without significant effects on T cell count, natural killer (NK) cell count or immunoglobulin levels. No patient developed anti-SCT400 antibodies during the course of the study. SCT400 serum half-life (T1/2), maximum concentration (Cmax) and area under the curve (AUC) generally increased between the first and fourth infusions (P