Pharmacokinetics and safety of IBI301 versus rituximab in patients with CD20 B-cell lymphoma: a multicenter, randomized, double-blind, parallel-controlled study.

This multicenter, randomized, double-blind, parallel-controlled trial aimed to compare the pharmacokinetics (PK) of IBI301 with rituximab in patients with CD20-positive (CD20) B-cell lymphoma, who achieved a complete response/unconfirmed complete response after standard treatments. Patients were randomized (1:1) to receive IBI301 or rituximab (375 mg/m, IV). Patients who continuously benefitted from the trial after the PK phase underwent the extension phase to receive up to three cycles of 3-month-cycle of rituximab/IBI301 maintenance therapy. PK was described using the area under the serum concentration-time curve from time zero to infinity (AUC), AUC from time zero to last quantifiable concentration (AUC), and maximum serum concentration (C). Pharmacodynamics (PD), incidence of adverse events and immunogenicity were evaluated. PK was defined equivalent, if 90% confidence intervals (CIs) for geometric mean ratios of PK endpoints fell within the margin of 0.8-1.25. Overall, 181 patients were enrolled in IBI301 (n = 89) and rituximab (n = 92) groups. Geometric mean ratios of AUC, AUC, and C were 0.91 (90% CI 0.85, 0.97), 0.91 (90% CI 0.86, 0.97), and 0.96 (90% CI 0.92, 1.01) between treatment groups, all within the bioequivalence range. Peripheral CD19 and CD20 B-cell counts were similar at each prespecified time point between the groups. No difference in immunogenicity was observed. The incidences of treatment-emergent adverse events (84.3% vs. 83.5%) and treatment-related AEs (56.2% vs. 61.5%) were comparable (IBI301 vs. rituximab). IBI301 was PK bioequivalent to rituximab in patients with CD20 B-cell lymphoma. The PD, safety, and immunogenicity profiles of IBI301 were similar to those of rituximab.