To gain clinical experience on the effectiveness and safety of switching from infliximab-Remicade(INX) to infliximab-biosimilar-CT-P13(INB) in patients with established rheumatic disease.
Patients receiving INX treatment at a rheumatology clinic consented to switching from INX to INB. Patient reported outcomes (PROs), disease-activity, and inflammatory markers were recorded at every visit. Generalized estimating equation models and time-dependent area under the curve (AUC) before/during INX and INB treatments were employed.
Thirty-nine consecutive patients [mean (SD) age 53 (11), 17 F] with various rheumatic diseases were switched to INB after a mean (SD) of 4.1 (2.3) years on INX. Thirty-one patients were on concomitant methotrexate. At a median (range) of 11 (7.5-13) months following the first administration of INB, AUCs for disease activity and PROs were similar for INX and INB. They were better compared to those prior to INX. Eleven patients (28.2%) discontinued INB, due to INX antidrug antibodies detected prior to INB infusion (n = 3); latent tuberculosis (n = 1); new-onset neurofibromatosis (n = 1); subjective reasons with no objective deterioration of disease (n = 6).
The clinical effectiveness of INB in both PROs and disease-activity measures was comparable to INX during the first year of switching, with no immediate safety signals. Subjective reasons (negative expectations) may play a role among discontinuations of biosimilars. Larger patient numbers and longer follow-up are necessary for confirming this clinical experience.