In-Use Stability of the Rituximab Biosimilar CT-P10 (Truxima) Following Preparation for Intravenous Infusion and Storage.

Background: CT-P10 is the first biosimilar of the anti-CD20 monoclonal antibody, rituximab. CT-P10 is currently available in over 51 countries worldwide, where it is approved in the same indications as its reference product rituximab. In-use stability studies are conducted for biologics to determine how conditions (e.g., temperature, light, humidity, length of time stored) affect drug quality following dilution and storage in infusion bags.

Objective: We evaluated the in-use stability of CT-P10 for intravenous infusion stored diluted in infusion bags over longer periods than currently recommended by manufacturer guidelines.

Methods: CT-P10, within the final month of its 36-month shelf life, was diluted to 1.0 or 4.0 mg/mL and stored at 2-8 °C in polyethylene or polyvinylchloride infusion bags for 2, 4, and 6 weeks. CT-P10 infusion bags were incubated at room temperature for 24 h before analysis. Analyses included detection of sub-visible particles, formation of impurities and determination of charge variants, and heavy- and light-chain content. Cell-based CD20 binding affinity and complement-dependent cytotoxicity were also assessed.

Results: Diluted CT-P10 solutions remained clear, colorless, and free of visible particles irrespective of type of infusion bag, target concentration, or timepoint. Protein concentrations, sub-visible particles, pH, osmolality, and molecular weight and charge variants were stable across all timepoints and variables. The binding affinity and potency of CT-P10 remained unchanged, indicating that the efficacy of the antibody was maintained following in-use preparation.

Conclusions: We demonstrated that CT-P10 was stable after refrigerated storage for up to 6 weeks followed by incubation at room temperature.