2020 Volume 32 Issue 1 Pages 13-20
Objectives: Remichek Q® is a test kit that qualitatively examines the blood concentration of infliximab（IFX）. In patients with rheumatoid arthritis（RA）who received IFX, Remicheck Q® was used to evaluate the blood concentration of IFX, and the relationship between IFX blood concentration and disease activity in clinical practice was examined.
Methods: This study included 57 patients at the Niigata Rheumatic Center diagnosed with RA and administered IFX. The study period was from October 2017 to April 2018. We retrospectively analyzed the patients’ background characteristics, disease activity, and IFX dose when the Remicheck Q® was conducted.
Results: Forty-four patients showed positive results（77%）. The DAS28-ESR tended to be lower in negative patients than in positive ones（2.67 ± 1.13 vs. 2.48 ± 0.44, p=0.775）. The CDAI（6.6 ± 6.5 vs. 3.1 ± 2.7, p=0.049）and SDAI（6.9 ± 6.8 vs. 3.2 ± 2.7, p=0.048）were significantly lower in negative patients than in positive ones. Doses of IFX were significantly lower negative patients than in positive ones（6.8 ± 2.6 mg/kg vs. 5.1 ± 2.4 mg/kg, p=0.032）, but prednisolone and methotrexate were not significantly different. All 13 negative patients achieved remission according to DAS28-CRP, and 5 achieved Boolean remission.
Conclusion: There are cases of good disease activity even when Remicheck Q® is negative. This is one of the reasons that there may be many cases in the Remicheck Q® negative group that are highly responsive to TNF inhibitor. It will be necessary to measure Remicheck Q® in patients with inadequate therapeutic effects early after the start of IFX to examine its usefulness.
