Tocilizumab Biosimilar Demonstrates Similar Safety, Efficacy for RA to Reference

Gerd R. Burmester, MD

Credit: Charité - Universitätsmedizin Berlin

CT-P47, a tocilizumab biosimilar, has demonstrated similar efficacy, pharmacokinetics, safety, and immunogenicity to reference (ref) tocilizumab in a phase 3 single transition study.¹

Findings from the study were presented by Gerd R. Burmester, MD, Professor of Medicine, Department of Rheumatology and Clinical Immunology, Charité - Universitätsmedizin Berlin, and Humboldt University and Free University, at the American College of Rheumatology (ACR) Convergence 2024, held in November in Washington, DC.

"Biosimilars offer cost savings and health gains for our patients and play an important role in treating rheumatic diseases," Burmester said in a statement.² "The RCT data of CT-P47 presented at ACR further establish the comparable safety and efficacy of biosimilars to their reference products.

The study included 471 patients with moderate to severe rheumatoid arthritis (RA) who had an inadequate response to at least 1 disease-modifying antirheumatic drug. Participants were randomized to receive 8 mg/kg of CT-P47 or ref-tocilizumab intravenously every 4 weeks up to Week 20. Prior to dosing at Week 24, 444 participants were randomized again to either maintain their treatments (CT-P47, 225; ref-tocilizumab, 109) or switch from ref-tocilizumab to CT-P47 (n = 110) treatment until week 48, followed by a 4-week follow-up period. Investigators assessed disease activity scores using 28 joints (DAS28) at Weeks 12 and 24.¹

Of the 444 participants re-randomized, 412 (92.8%) completed the study (CT-P47 maintenance, 210; ref-tocilizumab maintenance, 100; switch, 102). The investigators found that the mean change from baseline of DAS28 was not affected by the transition from ref-tocilizumab to CT-P47 at Week 24. Comparable improvements in clinical activity were observed up to Week 52 as measured by American College of Rheumatology (ACR)20/50/70 responses and remissions by clinical disease activity index (CDAI), simplified DA (SDAI), and Boolean-definition (v2.0). By Boolean definition, ACR/European Alliance of Associations for Rheumatology (EULAR) remission was met at week 24 by 67 (29.8%), 27 (24.8%), and 30 (27.3%) of the CT-P47 maintenance, ref-tocilizumab, and switch group, respectively; and at week 52 by 89 (39.6%), 46 (42.2%), and 56 (50.9%) of the groups, respectively. The mean pre-dose serum concentration was similar among the groups up to Week 52 (CT-P47 Maintenance,16.73 μg/mL; ref-tocilizumab Maintenance; 17.41 μg/m; switch, 17.32 μg/mL).¹

The safety profiles between maintenance groups and the switch group were generally comparable from weeks 24 to 52, with similar rates of at least 1 anti-drug antibody positive result at post-treatment after re-randomization between the groups. These rates were 4.4% in the CT-P47 maintenance group, 4.6% in the ref-tocilizumab maintenance, and 3.6% in the switch group. Additionally, 1.8% of patients in each group also had at least 1 neutralizing antibody positive result. There was 1 death deemed unrelated to treatment due to a treatment-emergent adverse event of peritonitis.¹

REFERENCES
1. Burmester G, Trefler J, Racewicz A, et al. Similar Efficacy, PK, Safety, and Immunogenicity of Tocilizumab Biosimilar (CT-P47) and Reference Tocilizumab in Patients with Moderate-to-Severe Active Rheumatoid Arthritis: Week 52 Results from the Phase III Single Transition Study. Presented at: ACR Convergence 2024; November 14-19; Washington, DC. Abstract 0502

2. Celltrion presents additional data from phase III randomized controlled trials to further support biosimilarity for CT-41 (biosimilar candidate of denosumab) and CT-P47 (biosimilar candidate of tocilizumab) at American College of Rheumatology (ACR) Convergence 2024. News release. Celltrion. November 18, 2024.