Background Patients who are being treated with anti-TNF therapy are at increased risk of developing active tuberculosis (TB) by reactivation of latent TB infection (LTBI) or de novo infection. SB2 is developed as a biosimilar of the infliximab reference product (INF). The primary results (30-week) and 54-week results of Phase III study have been reported^1,2.

Objectives To evaluate the prevalence of positive interferon-γ release assay (IGRA) at Screening, the incidence of positive seroconversion in IGRA, and the incidence of active TB in the patients receiving SB2 or INF for 54 weeks.

Methods This study is a randomised, double-blind phase III study. IGRA (QuantiFERON® Gold in-tube test) was performed at Screening, Week 22 and Week 54. Patients who have been diagnosed as active TB were excluded from the study. Patients with a positive IGRA test without any evidence of active TB could be enrolled after receiving TB prophylaxis treatment. Patients who newly seroconverted during the study also were recommended to receive TB prophylaxis.

Results Of 804 patients with IGRA results at Screening, 143 patients (17.8% of 804) had positive results. Among them, 46 patients (19 patients in SB2 and 27 patients in INF) were randomised after the 30-days of TB prophylaxis treatment and the others were excluded from the study. At Week 22 and 54 or early termination visit, respectively, 19 (6.6%) and 7 (2.4%) patients in SB2 and 20 (6.8%) and 7 (2.4%) patients in INF had newly positive IGRA results. Among the patients with positive IGRA results at Week 22, 73.7% (14/19) in SB2 and 50.0% (10/20) in INF were treated with anti-TB treatment. During the study period, there was 1 active TB case in each treatment group (tuberculous pleurisy in SB2 [Korea] and pulmonary tuberculosis in INF [Lithuania]) and there was no case of active TB reported in patients with positive IGRA results at Screening or Week 22.

Conclusions The incidence of positive seroconversion in IGRA was comparable between the two treatment groups. Among patients with positive IGRA results at Screening or Week 22, there were no cases of active TB and only 2 cases of active TB were reported in this study. IGRA is therefore an useful method to prevent active TB in anti-TNF treated RA patients.

1. Choe JY et al. Ann Rheum Dis. 2015–207764 [Epub ahead of print]

2. Choe JY et al. Arthritis Rheumatol. 2015; 67 (suppl 10), 2056

Disclosure of Interest P. Durez Consultant for: Samsung Bioepis, Speakers bureau: BMS, MSD, Lilly, UCB, Pfizer, E. Mysler: None declared, J. S. Smolen Consultant for: Abbvie, Amgen, Astra-Zeneca, Astro, Celgene, Glazo, Janssen, Lilly, Medimmune, MSD, Novartis-Sandoz, Pfizer, Roche, Samsung Bioepis, Sanofi, UCB, J.-Y. Choe Grant/research support from: Samsung Bioepis, Consultant for: Samsung Bioepis, J. Choi Employee of: Samsung Bioepis, Y. H. Rho Employee of: Samsung Bioepis