Celltrion presented positive Phase III data for CT-P47, a biosimilar candidate referencing RoActemra® in patients with moderate-to-severe rheumatoid arthritis (RA), at the Annual European Congress of Rheumatology (EULAR) 2024. Data from the Phase III comparative clinical trial demonstrated that the investigational biosimilar candidate, CT-P47, has an equivalent efficacy, and comparable safety and immunogenicity profile to the reference tocilizumab product. The Phase III study randomised 471 patients with moderate to severe RA to receive either CT-P47 or reference tocilizumab every 4 weeks at a dose of 8 mg/kg for the first 20 weeks.

Prior to dosing at week 24, patients receiving tocilizumab were re-randomised either to continue with reference tocilizumab or undergo transition to CT-P47 up to week 48. The primary endpoint was disease activity score 28 (DAS28) erythrocyte segmentation rate (ESR), improvement at weeks 12 and 24. The estimated differences between the two groups were -0.01 at week 12 and -0.1 at week 24, and the confidence intervals of the difference were entirely within the pre-defined equivalence margins at both timepoints (95% CI: -0.26 to 0.24 at week 12 and 90% CI: -0.30 to 0.10 at week 24).

The treatment groups were highly similar in terms of mean serum concentration up to week 32, incidence of treatment emergent adverse events and anti-drug antibody positivity, demonstrating comparable pharmacokinetics, safety and immunogenicity. In addition, a Phase I/III study compared pharmacokinetic (PK) similarity between the CT-P47 autoinjector (AI) and the pre-filled syringe (PFS) and evaluated the usability of the CT-P47 AI.2 The study showed PK similarity of the CT-P47 AI and the PFS in healthy subjects. In addition, higher usability of the CT-P47 AI was observed compared to the PFS in RA patients.

The CT-P47 AI was well tolerated, and no new safety signals were found in the study.