Background:Biological drugs have revolutionized the treatment of immune-mediated inflammatory diseases (IMIDs). Current guidelines reserve these drugs for patients with severe refractory disease.Biologic drugs are expensive, but as they reach patent expiry, the introduction of lower-cost biosimilars reduces their impact on health care budgets. It is estimated that NHS England could save £300 million by 2021 following the recent launch of adalimumab biosimilars [1]. As part of this process, there has been a mandatory switch of originator adalimumab to biosimilar adalimumab throughout the U.K.Objectives:To evaluate the impact of the switch to biosimilar adalimumab in individuals with inflammatory arthritis at two NHS trusts in the East of England and calculate the proportion and reasons for switch back to originator adalimumab or a second biosimilar at 12 weeks.Methods:Both hospitals ran dedicated ‘switch’ clinics. All patient records were reviewed retrospectively.Results:855 patients with different IMID switched from originator to biosimilar over 13 months. At 12 weeks, 730 patients (85%) maintained the switch, 71 patients (8.7%) switched back to the originator, and 54 patients (6.3%) switched to other biosimilars of the same drug.Table 1.Primary outcome analysis of switching from originator to adalimumab biosimilarDiagnosisTotal patient switched from originatorAverage duration (year) of use of originator before bio switch (for patients continue using bio switch)Total patients continuing (At 12 weeks)Average duration (year) of use of originator before bio switch (for patients switched back to originator)Total patients switched back to originator or other biosimilarRheumatoid Arthritis3567.9314 (88%)4.942 (12%)Axial Spondyloarthritis2606.4213 (82%)4.547 (18%)Psoriatic Arthritis2185.9187 (86%)2.931 (14%)Juvenile Arthritis163.714 (88%)4.52 (12%)Others52.22 (40%)0.83 (60%)Total8557.0730 (85%)4.2125 (15%)Table 2.Reasons for back to originator or another biosimilarReasons for back to originator or another biosimilarNumber back for IntoleranceNumber back for InefficacyPainful injection69BASDAI/Spinal Pain13Pain/Others19TJC, SJC, VAS4Rash/Allergic reaction5DAS3Headache5PsARC2Nausea4No Detail1Total102Total23%82%18%Conclusion:Switching to a biosimilar was successful in the vast majority of patients and is associated with significant saving. The list prices for originator Adalimumab is £9,155/person/year and £8,238/person/year for biosimilar Adalimumab respectively [2]. By switching we will save approximately £719,402 per annum (9.2% cost reduction).References:[1]NHS England. NHS set to save record £300 million on the NHS’s highest drug spend 2018 [cited 2018 November 30].https://www.england.nhs.uk/2018/11/nhs-set-to-save-record-300-million-on-the-nhss-highest-drug-spend/[2]https://bnf.nice.org.uk/medicinal-forms/adalimumab.htmlDisclosure of Interests:Rifat Mazumder: None declared, Marianne Loke: None declared, Chetan Mukhtyar: None declared, Karl Gaffney Grant/research support from: AbbVie, Celgene, MSD, Novartis, Pfizer, and UCB Pharma, Consultant of: AbbVie, Celgene, MSD, Novartis, Pfizer, and UCB Pharma, Speakers bureau: AbbVie, Celgene, MSD, Novartis, Pfizer, and UCB Pharma, Emese Balogh: None declared, Emerald Sekaran: None declared, Mushfika Sultana: None declared, Mabel Odonkor: None declared, Karen Miles: None declared

BackgroundTumour Necrosis Factor (TNF) inhibitors are routinely used in managing rheumatoid arthritis (RA), psoriatic arthritis (PsA) and spondyloarthritis (SpA). In 2012 and 2015, the patents for the Etanercept (ETN) and Infliximab (IFX) originator molecules expired in Europe respectively and the use of biosimilar ETN and IFX was approved for use in England.ObjectivesTo determine the proportion of rheumatology patients who experienced a flare of their disease following a switch from originator to biosimilar IFX or ETN and in those who flared, to determine whether disease control can be re-captured following reverting to the originator product.MethodsThis was a retrospective study of all patients switched from their originator IFX or ETN to their corresponding biosimilar product between July 2016 and July 2017 at a UK tertiary rheumatology centre. A total of 475 patients were identified by our Biologics team. Seventeen patients experienced a flare defined by: an increase in Disease Activity Score (DAS)28>1.2 points in RA, worsening of any of the Psoriatic Arthritis Response Criteria (PsARC) in PsA, an increase in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) of at least 1 unit in SpA, and worsening of swollen and tender joint count in our patient with adulthood juvenile idiopathic arthritis (JIA). Follow-up at 3 months determined disease re-capture, defined by an improvement in DAS28 score >1.2 units, improvement in at least two of the PsARC, one to be tender or swollen joint score, an improvement of BASDAI score and improved swollen and tender joint count in our patient with adulthood JIA.ResultsDiagnosisFlareRe-capture of disease control following switch back to originatorSide effects INFLIXIMABRA4/63 (6.3%)1/4 (25.0%)1/63 (1.6%)PsA2/15 (13.3%)0/20SpA2/19 (10.5%)1/2 (50.0%)1/19 (5.3%)JIA1/1 (100%)1/1 (100%)0ETANERCEPTRA4/238 (1.7%)4/4 (100%)6/238 (2.5%)PsA1/55 (1.8%)1/1 (100%)2/55 (3.6%)SpA3/84 (3.6%)2/3 (66.7%)2/84 (2.4%)Nine patients (9.2%) who switched to biosimilar IFX flared: four with RA, two with PsA, two with SpA and one with JIA. Of those, three patients (33.3%) were able to re-capture disease control on switching back to originator IFX. Two patients (2.0%) experienced side effects on switching to biosimilar IFX.Eight patients (2.1%) experienced a flare on switching to biosimilar ETN: four with RA, one with PsA and three with SpA. Of those, seven patients (87.5%) re-captured disease control on switching back to originator ETN. Ten patients (2.7%) experienced side effects on switching to biosimilar ETN.ConclusionsThe majority of our patients did well following the switch to biosimilar IFX and ETN.Patients who did flare on biosimilar ETN are more likely to re-capture their disease control than those who flared on biosimilar IFX.This adds to real-world evidence to support the European League Against Rheumatism recommendations to utilise biosimilar therapy in rheumatology practice, which is likely to include patients who differ from those enrolled in clinical trials; important when considering...

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