SAT0271 Secukinumab, a fully human anti-interleukin-17a monoclonal antibody, exhibits low immunogenicity in patients with psoriatic arthritis and ankylosing spondylitis during a 52-week treatment period
Authors: A. Deodhar, D. Gladman, I. McInnes, M. Ren, S. Spindeldreher, L. Pricop, B. Porter, J. Safi, A. Shete, G. Bruin
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Secukinumab (SEC), a fully human monoclonal antibody (mAb) that selectively targets IL-17A, is highly efficacious for the treatment of psoriatic arthritis (PsA) and ankylosing spondylitis (AS). mAb therapies may be associated with immunogenicity (IG) and production of anti-drug antibodies (ADAs) that may cause adverse events (AEs), and affect drug pharmacokinetics (PK) and clinical response. <h3>Objectives</h3> To assess the IG of SEC in PsA and AS patients (pts) treated with SEC for up to 52 weeks (W). <h3>Methods</h3> IG in pts with PsA (FUTURE 1–3 studies, n=1414) and AS (MEASURE 1–4 studies, n=1163) exposed to SEC was evaluated at baseline (BL) and at W 12, 16 (AS only), 24 and 52. Treatment emergent (TE)-ADA were defined as a positive ADA signal in ≥1 post-treatment sample in pts negative at BL. TE-ADA positive samples were analysed for drug-neutralising potential, SEC impact on PK, IG-related AEs and TE-ADA impact on efficacy through W52. <h3>Results</h3> Of 1414 treated PsA and 1163 treated AS pts with samples for IG evaluation, 5 (0.35%) and 8 (0.68%) developed TE-ADAs respectively, over 52 weeks (Table). All but 1 PsA pt were biologic naïve; 2/5 PsA and 1/8 AS pts received concomitant methotrexate, 2/8 AS pts received concomitant sulfasalazine. Associations between TE-ADAs and SEC dose, frequency or mode of administration were not observed. Other than 1 PsA pt, all TE-ADAs were non-neutralising and none were associated with any IG-related AE. All TE-ADAs were associated with normal PK and none were associated with loss of SEC efficacy over 52 weeks. <h3>Conclusions</h3> SEC treatment was associated with a low incidence of IG in PsA and AS pts, as shown by TE-ADA detection in only 0.35% PsA pts and 0.68% AS pts over 52 weeks in a database of&gt;2500 pts, which is consistent with the low incidence of IG (0.4%) seen with SEC in pts with plaque psoriasis.<sup>1</sup> <h3>Reference</h3> [1] Reich K, et al. Br J Dermatol2017;176:752. <h3>Disclosure of Interest</h3> A. Deodhar Grant/research support from: AbbVie, Amgen, Eli Lilly, GSK, Janssen, Novartis, Pfizer and UCB, Consultant for: Eli Lilly, Janssen, Novartis, Pfizer and UCB, D. Gladman Grant/research support from: Amgen, AbbVie, BMS, Celgene, Eli Lilly, Janssen, Novartis, Pfizer and UCB, I. McInnes Grant/research support from: AbbVie, Amgen, BMS, Celgene, Janssen, Lilly, Novartis, Pfizer and UCB, Consultant for: AbbVie, Amgen, BMS, Celgene, Janssen, Lilly, Novartis, Pfizer and UCB, Speakers bureau: AbbVie, Amgen, BMS, Celgene, Janssen, Lilly, Novartis, Pfizer and UCB, M. Ren Employee of: Novartis, S. Spindeldreher Shareholder of: Novartis, Employee of: Novartis, L. Pricop Shareholder of: Novartis, Employee of: Novartis, B. Porter Shareholder of: Novartis, Employee of: Novartis, J. Safi Shareholder of: Novartis, Employee of: Novartis, A. Shete Shareholder of: Novartis, Employee of: Novartis, G. Bruin Shareholder of: Novartis, Employee of: Novartis