Guidelines for the treatment of psoriatic arthritis with biologics

classification criteria. Psoriasis is a recognised feature of SpA within these criteria. This is particularly crucial in
axial PsA as the disease is less likely to be bilateral and to involve the sacro‐iliac joints meaning that patients
are less likely to fulfil the modified New York criteria for ankylosing spondylitis.
Recommendations
• Anti‐TNF therapy should be considered for those patients with active axial psoriatic arthritis
according to the recommendation of the BSR guidelines for ankylosing spondylitis (REF).
(Grade A). Consensus score 9.8
CONCOMITANT PRESCRIBING WITH ANTI‐TNF
Many of the randomised controlled trials of anti‐TNF therapy in PsA used subgroup analysis to compared
patients on concomitant MTX with those who were on anti‐TNF monotherapy. There was no clear difference
between the groups, although these trials were not designed or significantly powered to assess the effect of
concomitant therapy.
Registry data from the South Swedish Arthritis Treatment Group have shown that persistence with biologics is
increased with concomitant MTX use [25] . Specifically it seemed that the advantage of MTX was related to a
lower rate of dropouts for adverse events [26]. Both of these analyses combined all anti‐TNF agents and did
not assess the drugs independently. Subsequently a smaller analysis of patients treated only with etanercept
did not confirm the improved persistence with concomitant MTX [27]. The authors suggested that the
advantage of concomitant MTX seen in the Swedish study may have been due to the patients on infliximab
(around 40% of the registry patients) and that concomitant MTX may be less important with etanercept or
adalimumab [27]. Registry data from the British Society for Rheumatology Biologics Register (BSRBR) has
shown similar EULAR response rates in patients receiving concomitant MTX, other DMARDs and biologic
monotherapy [28].
Ciclosporin is the only DMARD evaluated specifically with anti‐TNF therapy. A small open‐label study recruited
patients on etanercept with ongoing active skin disease and added ciclosporin (3mg/kg/day) to their
etanercept. The majority of patients showed an improvement in skin psoriasis over the 24 week study period
with only one withdrawal due to adverse events [29]. However the long term effects of combining anti‐TNF
therapy and ciclosporin are not known, and the combination is not recommended in dermatological practice.
Outcome measures
As stated above, the PsARC is the current recommendation for response assessment in peripheral arthritis.
The ACR response criteria have also been shown to be discriminative in polyarticular PsA [14], but are
generally too cumbersome and time consuming for routine clinical practice. Other composite arthritis
measures have been validated in PsA. The EULAR responses, based on the DAS and DAS28 scores have been
shown to be responsive in polyarticular disease [29] but there are numerous concerns about their use in the
general PsA population (i.e. lack of validity in oligoarticular disease or those with predominant lower limb
involvement, remission cut off validated in RA but not in PsA , global disease activity may be influenced by
other aspects of psoriatic disease [such as enthesitis, psoriasis, axial disease], PsA patients show a less linear
relationship between disease activity and acute phase response).
The disease activity in reactive arthritis (DAREA) score was originally developed for use in reactive arthritis [30]
but has recently been assessed and validated in two cohorts of PsA patients[31, 32] and the authors have
proposed using it in PsA as the disease activity in PsA (DAPSA) score. The DAPSA includes joint counts, patient
reported outcome measures (PROMs) and an inflammatory marker and has been shown to be responsive in
polyarticular disease. The DAPSA may represent a useful measure of PsA peripheral arthritis activity in future
as it is feasible in clinic and allows a measure of disease state rather than just a response outcome such as the
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