A multi-center, open-label, randomized, parallel-controlled phase II study comparing pharmacokinetic, pharmacodynamics and safety of ripertamab (SCT400) to rituximab (MabThera®) in patients with CD20-positive B-cell non-Hodgkin lymphoma.

Objective: This multi-center, open-label, randomized, parallel-controlled phase II study aimed to compare the pharmacokinetics (PK), pharmacodynamics (PD) and safety profile of ripertamab (SCT400), a recombinant anti-CD20 monoclonal antibody, to rituximab (MabThera^®) in patients with CD20-positive B-cell non-Hodgkin lymphoma (NHL).

Methods: Patients with CD20-positive B-cell NHL who achieved complete remission or unconfirmed complete remission after standard treatment were randomly assigned at a 1:1 ratio to receive a single dose of ripertamab (375 mg/m²) or rituximab (MabThera^®, 375 mg/m²). PK was evaluated using area under the concentration-time curve (AUC) from time 0 to d 85 (AUC_{0-85 d}), AUC from time 0 to week 1 (AUC_{0-1 w}), AUC from time 0 to week 2 (AUC_{0-2 w}), AUC from time 0 to week 3 (AUC_{0-3 w}), AUC from time 0 to week 8 (AUC_{0-8 w}), maximum serum concentration (C_max), terminal half-life (T_1/2), time to maximum serum concentration (T_max) and clearance (CL). Bioequivalence was confirmed if the 90% confidence interval (90% CI) of the geometric mean ratio of ripertamab/rituximab was within the pre-defined bioequivalence range of 80.0%-125.0%. PD, immunogenicity, and safety were also evaluated.

Results: From December 30, 2014 to November 24, 2015, a total of 84 patients were randomized (ripertamab, n=42; rituximab, n=42) and the PK analysis was performed on 76 patients (ripertamab, n=38; rituximab, n=38). The geometric mean ratios of ripertamab/rituximab for AUC_{0-85 d}, AUC_0-inf, and C_max were 96.1% (90% CI: 87.6%-105.5%), 95.9% (90% CI: 86.5%-106.4%) and 97.4% (90% CI: 91.6%-103.6%), respectively. All PK parameters met the pre-defined bioequivalence range of 80.0%-125.0%. For PD and safety evaluation, there was no statistical difference in peripheral CD19-positive B-cell counts and CD20-positive B-cell counts at each visit, and no difference in the incidence of anti-drug antibodies was observed between the two groups. The incidences of treatment-emergent adverse events and treatment-related adverse events were also comparable between the two groups.

Conclusions: In this study, the PK, PD, immunogenicity, and safety profile of ripertamab (SCT400) were similar to rituximab (MabThera^®) in Chinese patients with CD20-positive B-cell NHL.