THU0146 Impact of anti-Drug Antibodies on Efficacy and Safety Up To Week 24 from A Phase III Study Comparing SB5 (An Adalimumab Biosimilar) with Adalimumab Reference Product in Patients with Moderate To Severe Rheumatoid Arthritis despite Methotrexate Therapy

BackgroundSB5 is a biologic agent developed as a biosimilar of the adalimumab reference product (ADL). The primary efficacy and safety results from a phase III study in rheumatoid arthritis (RA) patients have been reported previously1. Immunogenicity to monoclonal antibodies may affect patients' safety and efficacy.ObjectivesTo compare efficacy and safety results by anti-drug antibody (ADA) status in patients with RA treated with SB5 or ADL (with background Methotrexate, MTX) up to Week 24.MethodsPatients with moderate to severe RA despite MTX treatment were randomly assigned to receive 40 mg of either SB5 or ADL administered subcutaneously every other week. Efficacy, safety, and immunogenicity were measured.ResultsThe ADA incidence up to Week 24 was 32.8% in SB5 and 31.5% in ADL. In both ADA positive and ADA negative subgroups, ACR responses and other efficacy endpoints were comparable between SB5 and ADL up to Week 24. Within SB5, there was a trend towards decreased efficacy (ACR20, ACR50, ACR-N, change in DAS28 from baseline, and in patients with remission based on DAS28, SDAI or CDAI) in the ADA positive subgroup compared to the ADA negative subgroup. Within ADL, there was a trend towards decreased efficacy for patients in remission based on DAS28, SDAI or CDAI in the ADA positive subgroup compared with the ADA negative subgroup, but other efficacy endpoints were comparable. The safety profiles of SB5 and ADL were generally comparable in both ADA positive and ADA negative subgroups. Within each treatment group, the safety profiles were comparable between ADA positive and ADA negative subgroups. Among ADA negative subgroup, 2.2% in SB5 and 3.8% in ADL experienced ISR and among ADA positive subgroup, 4.5% in SB5 and 1.2% in ADL experienced ISRs.ConclusionsThe efficacy was comparable between SB5 and ADL regardless of 24-week overall ADA status. Patients with positive ADA status were more likely to have reduced efficacy in SB5, but there was a weaker correlation between the presence of ADA and clinical efficacy in ADL. The safety was generally comparable between SB5 and ADL regardless of the 24-week overall ADA status. Safety was generally comparable between ADA negative and ADA positive subgroups in both treatment groupsReferencesWeinblatt ME et al. Arthritis Rheumatol. 2015; 67 (suppl 10), 8LDisclosure of InterestM. C. Genovese Consultant for: Samsung Bioepis, M. Weinblatt Consultant for: AbbVie, Samsung Bioepis, Amgen, E. Keystone Grant/research support