Fifty-two-week data show that efficacy was maintained in patients with rheumatoid arthritis (RA) when switching from reference tocilizumab (Actemra; Genentech) to tocilizumab-anoh (Avtozma, CT-P47; Celltrion, Inc.), a biosimilar. Additionally, the data—which were published by study investigators in Clinical Drug Investigation—also demonstrated comparable pharmacokinetics, safety, and immunogenicity between the biosimilar and its reference product.1
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About the Trial
Trial Name: A Study to Compare Efficacy and Safety of CT-P47 and RoActemra in Patients With Rheumatoid Arthritis
ClinicalTrials.gov ID: NCT05489224
Sponsor: Celltrion
Completion Date: November 23, 2023
Tocilizumab is a biologic medication that is FDA-approved to treat adults with moderate to severe RA, giant cell arteritis, interstitial lung disease–complicated systemic sclerosis, juvenile idiopathic arthritis, and other inflammatory-based symptoms. The treatment is administered either as a subcutaneous injection or an intravenous (IV) infusion. When administered as an injection, it can be given every week or every other week either in the abdomen or thigh, whereas the IV infusion is given once every 4 weeks. The American College of Rheumatology notes that tocilizumab may be taken alone or with other medications; however, it is not recommended to be used with other biologic medications.2
Because it is a biosimilar, Avtozma is highly similar and does not have any clinically meaningful differences in efficacy, safety, pharmacokinetics, and immunogenicity compared with its reference product. It is a recombinant humanized monoclonal antibody that acts as an IL-6 receptor antagonist.3 In addition to its previous FDA-approved indications, IV Avtozma was recently approved for the treatment of cytokine release syndrome in both pediatric and adult patients aged 2 years and older.4
To further demonstrate IV Avtozma’s efficacy, safety, immunogenicity, and pharmacokinetics in patients with moderate to severe RA, investigators initiated a randomized, double-blind, multicenter, phase 3 clinical trial (NCT05489224).5 For this study, 444 patients with RA were randomly assigned to receive Avtozma or Actemra every 4 weeks (8 mg/kg IV) up to week 20. At the 24-week period, patients receiving Avtozma continued maintenance treatment, whereas those on the reference product were randomly assigned again to continue the reference product or switch to its biosimilar as maintenance until week 48 (treatment period 2). Following week 48, patients were followed up until week 52.1,5
During treatment period 2, 225 patients continued receiving the Avtozma, 109 continued receiving Actemra, and the remaining 110 switched from the reference to the biosimilar. The investigators reported that, during this treatment period, efficacy findings were comparable between the groups. By week 52, the mean changes from baseline in Disease Activity Score in 28 joints-erythrocyte sedimentation rates (DAS28-ESR; the primary end point) were about –4.279, –4.231, and –4.376 in the Avtozma maintenance, Actemra maintenance, and Avtozma switched groups, respectively. Notably, joint damage progression over 1 year was minimal in all 3 groups, and drug serum concentrations were considered relatively consistent throughout the duration of treatment period 2. The safety profile and antidrug antibody-positive conversion rate (less than 5% in each group) were also similar.1
These findings are consistent with previous 32-week findings, which had also shown efficacy equivalence, comparable pharmacokinetics, safety, and immunogenicity profiles between the biosimilar and its reference product. Similar to the 52-week findings, these data also showed high similarities between the 3 groups.6
“DAS28-ESR may not be the most appropriate tool for assessing agents that target the IL-6 pathway, given that these therapies can reduce ESR independently of clinical improvement; however, this is not a significant limitation, as tocilizumab was used in all 3 treatment groups in this study,” the study authors wrote. “With respect to the study design limitations during [treatment period 2], the numbers of patients in the [Actemra] maintenance and [Avtozma] switched groups were lower than in the [Avtozma] maintenance group because of the second randomization. [Treatment period 2] of this study was not designed for statistical comparisons of equivalence between the [Avtozma] and [Actemra] maintenance groups and the [Avtozma] switched group; however, the results from [treatment period 2] in this study provide valuable data on switching from a reference product to a biosimilar.”1