Objectives: To assess clinical activity, ultrasound synovitis and drug levels in rheumatoid arthritis (RA) patients receiving anti-TNFα therapy with extended interval of administration (EIA). Methods: Prospective observational study. Population: RA patients, in clinical remission, receiving adalimumab (ADL) or etanercept (ETN) with EIA. Clinical activity was assessed by DAS28-ESR, DAS28-CRP, CDAI and SDAI scores at each visit. Twelve-joint ultrasound assessment (elbows, wrists, 2nd and 3rd

more »

... arpophalangeal joints, knees and ankles) was performed evaluating synovitis through B-mode (BM) and Color Doppler signal (CD). A BM and CD score was calculated summing the highest score from each joint to a maximum of 36 points. We consider positive score >1 point. Serum drug levels were measured using Promonitor ® ELISA kits (Progenika Biopharma-Grifols, Spain). Results: A total of 39 patients were included since February 2011 to December 2016. One patient was excluded due to blindness violation and 2 patients never reduced anti-TNFα due to low drug levels. 31 patients were women (82%) and the mean age was 61 (39-81) years. Most patients were RF positive (87%) and ACPA positive (74%). 22 patients were with ADL treatment and 16 with ETN. 32 patients (82%) were with DMARD concomitant treatment (18 MTX (46%), 11 LEF (18%), 2 HCQ (5%), 1 SSZ (2%)) and 7 patients were with low-dose CS (18%). Mean time from diagnosis was 14,95 years (range 2,15 -52,31) and Mean time with current biologic drug was 4,21 years (range 1,39 -11,07). Nine patients (24%) returned to standard interval due to worsening of clinical activity and one discontinued treatment due to septic arthritis. All of them returned to clinical remission and no anti-drug antibodies were detected. Clinical activity scores, ultrasound scores and drug levels are summarized in table 1.