P751 Time course of the incidence and magnitude of anti-drug antibodies to adalimumab and ABP 501 among patients on concomitant immunomodulatory therapy

Abstract

Introduction: Immunomodulatory therapy with agents such as methotrexate and corticosteroids can impact the development of anti-drug antibodies (ADAs) to monoclonal antibodies such as adalimumab used to treat inflammatory bowel disease. ABP 501 (AMJEVITA; adalimumab) is an approved biosimilar to adalimumab. Here we report results from a Phase 3 study in patients with rheumatoid arthritis (RA) comparing the incidence of ADAs and the relative magnitude of the ADA response between ABP 501 and adalimumab reference product (RP) on background methotrexate (MTX). Aims and Methods: We analysed data from a randomized, double-blind, 26 week, 1:1 active-controlled study designed to show clinical equivalence between ABP 501 40 mg and adalimumab 40 mg subcutaneously every two weeks among adalimumab-naive adult patients with moderate to severe RA who had an inadequate response to MTX. Patients were required to receive a stable dose of MTX (range 7.5 to 25 mg/week) for the duration of the study. Patients were also allowed to remain on oral corticosteroids at a dose of