LAUSR

Biosimilar drugs has supposed a huge savings in our health systems and there are data that conclude that they work as original molecules when we making these switchings. There are limited studies that analize these patients across the time (1-3).Long term follow up of patients after switching from original etanercept to biosimilar drug.We reviewed 187 patients who started Etanercept original in Rheumatology department at Navarra Hospital Complex and their switch to Etanercept biosimilar with a follow-up of 18 months.The switch was performed in 176 patients with rheumatoid arthritis (RA), spondyloarthritis (SpA) and psoriatic arthritis (PsA).At 18 months of follow-up 26,1% discontinued treatment; 13% at 6 months, 9,1% at 12 months and 4% patients at 18 months. The median time in etanercept original drug before switching was 52 months.There were 46 withdrawal patients with etanercept biosimilar: 34 inefficacy, 3 skin reaction, 2 malignancies (lymphoma and GIST), 1 injection site reaction, 1 headache, 1 diarrhea, 1 recurrent urinary infection, 1 heart failure and 2 deaths. 25 patients returned to Etanercept original but 3 did not achieve good response; all of them in RA group.In our series 50 % of withdrawal happened at 6 months of follow-up. 73,9% had a good response with etanercept biosimilar at 18 months. The main reason to stop biosimilar drug was inefficacy.Longer-term follow-up and greater number of patients are necessary to ratify these data.[1]Selmi C, et al. BENEFIT: real-world effectiveness of SB4 after transition from reference etanercept in rheumatoid arthritis and axial spondyloarthritis. Clin Exp Rheumatol. 2020 Jun 30. Epub ahead of print.[2]Glintborg B, et al. To switch or not to switch: results of a nationwide guideline of mandatory switching from originator to biosimilar etanercept. One-year treatment outcomes in 2061 patients with inflammatory arthritis from the DANBIO registry. Ann Rheum Dis. 2019 Feb;78(2):192-200.[3]Tweehuysen L, et al. Open-Label, Non-Mandatory Transitioning From Originator Etanercept to Biosimilar SB4: Six-Month Results From a Controlled Cohort Study. Arthritis Rheumatol. 2018 Sep;70(9):1408-1418.Table 1.WITHDRAWAL (months)BACK TO ENBREL (n)CONTINUEENBREL (n)TIME TO SWITCH (months)REASON FOR WITHDRAWALInefficacyA.event*CancerDeathRA2211853 14521PsA166653,515001SpA888455300TOTAL4625225234822*Infections (1), Heart failure (1), skin reaction (3), injection point reaction (1)RA: rheumatoid arthritis; PsA: psoriatic artrhritis; SpA: spondyloarthritisNone declared