A systematic literature review of the Medline database up to August 2013 was carried out by the authors to identify double-blind, parallel-group, randomized, controlled trials (RCTs) with full article obtainable. The Cochrane Highly Sensitive Search Strategy [2] was applied to identify randomized, controlled publications and was combined with the disease MeSH terms ‘arthritis, rheumatoid’ and the drug names. The authors used a Bayesian Mixed Treatment Comparison method, since this allowed pairwise comparison of treatments with different comparators. This was necessary, as biosimilar infliximab is only compared to originator infliximab in the PLANATRA RCT [3], while other biologicals are compared to placebo in most of the studies. Efficacy endpoints were improvement rates by the American College of Rheumatology criteria (ACR20 and ACR50) at week 24 and the occurrence of serious adverse events was considered to assess the safety of the biologicals.

The authors included thirty-six RCTs in the meta-analysis. Thirty-four studies involving 15,044 patients reported results for ACR20 response at week 24, and thirty-five studies involving 14,535 patients reported ACR50 response at week 24. In the meta-analysis, all the biologicals proved to be superior to placebo. For ACR20 response, certolizumab pegol showed the highest odds ratio (OR) compared to placebo, OR = 7.69[95% CI = 3.69–14.26], followed by abatacept OR = 3.7[95% CI = 2.17–6.06], tocilizumab OR = 3.69[95% CI = 1.87–6.62] and biosimilar infliximab OR = 3.47[95% CI = 0.85–9.7]. For ACR50 response, certolizumab pegol showed the highest OR compared to placebo OR = 8.46[3.74–16.82], followed by tocilizumab OR = 5.57[95% CI = 2.77–10.09] and biosimilar infliximab OR = 4.06[95% CI = 1.01–11.54]. The results of pairwise comparisons did not show significant differences between the efficacy of biosimilar infliximab and the other biologicals.

The authors included 30 studies with 14,708 patients in the safety analysis that reported the occurrence of serious adverse events at week 24. The results show no statistically significant difference between biosimilar infliximab and placebo, OR = 1.87[95% CI = 0.74–3.84]. Regarding the pairwise comparison of the treatments, the authors found no significant difference in the safety of biosimilar infliximab and other biologicals.

The authors concluded that the meta-analysis, which involved a total of 15,044 RA patients, ‘demonstrated that there is no significant difference in the efficacy and safety of biosimilar infliximab and other biologicals in RA’. They added that the results might support clinical as well as financial decision-making, providing evidence on the similar efficacy and safety of biosimilar infliximab and other biologicals indicated in RA.

Conflict of Interest
The authors of the research paper [1] declared that the study was supported by an unresetricted grant from EGIS Pharmaceuticals and the Center for Public Affairs Studies Foundation. 

For full details of the authors’ conflicts of interest, see the research paper [1].

Abstracted by Petra Baji, Department of Health Economics, Corvinus University Budapest, Hungary.

Editor’s comment
Readers interested to learn more about biosimilars are invited to visit www.gabi-journal.net to view the following manuscript published in GaBI Journal: 

Biosimilars: extrapolation of clinical use to other indications

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References
1.  Baji P, Péntek M, Czirják L, et al. Efficacy and safety of infliximab-biosimilar compared to other biological drugs in rheumatoid arthritis: a mixed treatment comparison. Eur J Health Econ. 2014;15 Suppl 1:S53-64. 
2.  Yoo DH, Hrycaj P, Miranda P, et al. A randomised, double-blind, parallel-group study to demonstrate equivalence in efficacy and safety of CT-P13 compared with innovator infliximab when coadministered with methotrexate in patients with active rheumatoid arthritis: the PLANETRA study. Ann Rheum Dis. 2013;72(10):1613-20. 
3.  Higgins JPT, Green S. Cochrane handbook for systematic reviews of interventions. Version 5.0.2 [updated 2009 Sep]. The Cochrane Collaboration; 2009. 

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