Background Gradually increasing the interval between doses (or reducing the doses) of anti-TNF drugs does not appear to increase the risk of relapse or progression among patients with established rheumatoid arthritis (RA) and ankylosing spondylitis (AS) who have achieved remission.

Purpose To describe and compare the effectiveness of stepping down strategy (SDS) with adalimumab vs. etanercept in RA-AS patients.

Materials and methods Transversal and analytical study of adalimumab and etanercept prescriptions (AP, EP) in RA-AS patients registered in the outpatient pharmacy department in a 680-bed teaching hospital (FarmaTools 2.4) from 03/2012 to 06/2013. We defined SDS as increasing a dose interval to > 115% or reducing a dose to <85% of the standard range as defined in SPC. We collected demographic data (sex and age) and SDS effectiveness (days on remission -DAS28 < 2.4-). Comparisons and descriptive statistics were performed with SPSS 15.0.

Results 278 patients were evaluated, 174 with RA (62.5% men, 37.5% women, mean age = 56.6 ± 12.4 years) and 104 with AS (35.6% men, 64.4% women, mean age = 48.7 ± 12.5 years). Percentage of AP vs. EP, in RA (52.8% vs. 47.2%, p = 0.556), in AS (50.9% vs. 49.1%, p = 0.523). Overall, the percentage of SDS prescriptions in RA and AS were 46.5% vs. 31.7% (p = 0.001), respectively. Percentage of AP SDS vs. EP SDS, in RA (58.3% vs. 44.6%, p = 0.004), in AS (34.0% vs. 38.6%, p = 0.124). Stepped down adalimumab was less effective than stepped down etanercept in RA (median = 362 days vs. 438 days, p = 0.003), but similar in AS (median = 289 days vs. 318 days, p = 0.364).

Conclusions The proportion of patients with AP and EP is very similar in RA and AS, but SDS is more frequent in RA, mainly with adalimumab. In RA, etanercept SDS is significantly more effective than adalimumab SDS, but there was no difference between them in AS.

No conflict of interest.