A Comparison of the Immunogenicity of Intravenous BAT1806, a Tocilizumab Biosimilar, and Its Reference Product

Biosimilars need to demonstrate similarity in terms of quality, pharmacokinetics (PK), efficacy, safety, and immunogenicity. Here, we report the outcome of a comprehensive evaluation of the immunogenicity of the biosimilar BAT1806 compared with the tocilizumab reference product (TCZ).

We conducted a post hoc analysis of study BAT1806-001-CR, a comparative PK study in healthy male volunteers (n = 129), and BAT1806-002-CR, a phase III, 52-week trial in patients with rheumatoid arthritis (n = 621). Anti-drug antibodies (ADA), ADA titers, and neutralizing ADA were measured, and their impact on PK, safety, and efficacy parameters were assessed.

In BAT1806-001-CR, treatment-induced ADA were observed in 37.8% of participants for the BAT1806 group, 28.6% for the EU-sourced TCZ group, and 31.0% for the US-sourced TCZ group, without an impact on PK and safety. In BAT1806-002-CR after 52 weeks, 28.2% of participants in the BAT1806 group developed treatment-induced ADA, compared with 24.0% in the TCZ group and 19.7% of participants who initiated TCZ and switched to BAT1806 at week 24. ADA-positive participants reported lower geometric mean serum tocilizumab trough concentrations than ADA-negative participants in all treatment groups. ADA-positive participants achieved similar efficacy outcomes to ADA-negative participants in all treatment groups. ADA were not associated with an incremental risk of treatment-emergent adverse events or hypersensitivity in any of the treatment groups.

The results of these post hoc analyses did not indicate any clinically relevant differences in the immunogenicity profile of intravenously administered BAT1806 compared with TCZ.

ClinicalTrials.gov identifiers, NCT03606876, NCT03830203.