P010 Real world experience of switching to an adalimumab biosimilar; different outcomes for axial spondylitis, psoriatic and rheumatoid arthritis

Abstract Background/Aims Adalimumab is licenced to treat a variety of autoimmune conditions including inflammatory arthropathies. Switching stable patients from the bio-originator Humira biosimilars has been strongly promoted on economic grounds and presumed equitable interchangeability regarding efficacy tolerance across all disease indications. Our aims were assess adalimumab biosimilar retention rates up 1 year in with axial spondylitis (AS), psoriatic (PsA) rheumatoid arthritis (RA) routine care setting determine by subtype reasons for switching back Humira. Methods Retrospective observational study, utilising data St. George’s Hospital Rheumatology Biologics Database. Demographic details, duration discontinuation switched an recorded year. Results 238 (female 54.5%) biosimilar: AS n = 95, PsA 82, RA 61. Overall, 53% over 1-year period, female 57%. By subtype, rate at was 36%, 61%, 46%. reason adverse effect or device specific problem (AE) 59% loss (IR) 41%. AEs 98% pain other injection site reactions. was: IR, 41% AE, 22% 78% 27% 73% AE. Conclusion Projected cost savings switch programme not achieved, returning later. indication had lowest biosimilar, whom more likely than AE trigger switch, twice as prevalent PsA. most back, citrate buffer solution this. The efficacy, particularly patients, implies that between products cannot be assumed, projected saving advantages may overestimated. Disclosure F.A.A. Holden: None. D. Hill: P. Kiely: