AB0289 EFFICACY, SAFETY AND IMMUNOGENICITY IN PATIENTS WITH RHEUMATOID ARTHRITIS COMPARING PF-06410293 (ADL-PF), AN ADALIMUMAB (ADL) BIOSIMILAR, AND REFERENCE ADL: RESULTS FROM WEEK 26–52 OF A DOUBLE-BLIND, RANDOMISED PHASE 3 STUDY INCLUDING PATIENTS WHO SWITCHED FROM ADL-PF TO REFERENCE ADL AT WEEK 26

Background: Biological disease-modifying antirheumatic drugs (bDMARDs) caused a paradigm shift in the treatment of rheumatoid arthritis (RA). However, their high cost is a burden for patients and the national medical economy. Objectives: To analyze the long-term outcomes of patients with RA who achieved a bio-free condition (BF) with adalimumab (ADA). Methods: We followed 25 patients (male 6, female 19) who discontinued ADA with clinical remission (CR), and one female with a low disease activity (LDA), over 19.4 ±7.8 months of ADA treatment1). At the introduction of ADA, the average age was 51.2 ± 11.9 years old, and the average disease duration was 45.1 ± 48.4 months. The disease activity measured by disease activity score based on C-reactive protein (DAS28-CRP) was defined as follows: CR, 4.1, since the DAS28-CRP tends to be lower than the DAS28-based on the erythrocyte sedimentation rate in Japanese patients 2). Results: We lost one patient with a transfer to another hospital. Four patients re-started ADA due to flare (DAS28-CRP>2.7) but achieved CR (in BF) again with the intensification of the treatment (dose increase or initiation of prednisolone [PSL] and/or conventional synthetic [cs] DMARDs such as tacrolimus or iguratimode). The DAS28-CRP significantly decreased from 3.45 ± 1.32 at base line (BL) to 1.55 ± 0.41 (p Conclusion: BF can be sustained with an adequate dose of MTX and combination of csDMARDs. References: [1]Ito S, et al. An analysis of the biological disease-modifying antirheumatic drug-free condition of adalimumab-treated rheumatoid arthritis patients. Intern Med 58: 511-519, 2019 [2]Inoue E, et al. Comparison of Disease Activity Score (DAS)28-erythrocyte sedimentation rate and DAS28- C-reactive protein threshold values. Ann Rheum Dis. 66:407-409, 2007. Disclosure of Interests: Satoshi Ito Speakers bureau: Abbvie,Eisai, Shunsuke sakai: None declared, Yoichi Kurosawa: None declared, Daisuke Kobayashi: None declared, Ryo Okabayashi: None declared, Asami Abe: None declared, Hiroshi Otani: None declared, Kiyoshi Nakazono: None declared, Akira Murasawa: None declared, Ichiei Narita: None declared, Hajime Ishikawa: None declared