Background Psoriatic Arthritis (PsA), due to the involvement of both the skin and joints, is one of the rheumatic diseases that can most benefit from multidisciplinary work.The collaboration improved the management of difficult-to-diagnose and/or uncontrolled disease in addition to the early diagnosis and treatment of psoriatic arthritis.Biological therapy is a well-established treatment for PsA. Taking into account the proven long-term efficacy and the cost of these treatments, the Psoriatic Arthritis Units (PAU) try to consider new strategies of doses as an alternative to the standard dosage in those suitable patients whom achieved clinical remission.

Objectives We present the demographic, economic, and disease activity data of the 88 patients with PsA who were seen in our PAU in the last year.

Methods Distribution: 71,6% Peripheric 11,4% axial; 17% both. The average age was 49.55 years, with 41 males and 47 females. Comorbidities: dyslipidemia 21,6%, Hypertension 18,2%, Diabetes Mellitus 10,2%, Obesity 6,8%, Smoker 22,7%.

Results 63, 6% were treated with at least one systemic treatment (47,7% methotrexate, 8% salazopyrin, 5,7% combined MTX/SSZ and 2,2% others drug). Only 26,1% were treated with Biological therapy (8%adalimumab;8%etanercept;5,7%certolizumab;2,3% ustekinumab and2,3%infliximab). 30,43% of all patients were under lower-dose treatment according to technical data.We reduced the biological dosage after achieving PGA ≤1 (clear or almost clear) and DAS28- ERS <2, 6 for at least 12 months. Results: 57% with adalimumab 40mg every 21 days; 28% with etanercept (25 mg /week and 25 mg/10 days) and 14% with ustekinumab without induction dose.We calculated the cost savings in euros of the direct expenditure of the pharmaceutical procedures with the modification of the dosage according to each biological treatment. Adalimumab 4295, 25 euros/year/patient (total: 17,181 euros/year) Etanercept (25 mg /week and 25 mg/10 days) 3.937,96 euros /year- 2.503,8 euros/year; Ustekinumab 2.642,96 euros/year. Subsequently, the total savings amount to 26.265,72 euros /year. These savings translate to at least 3 more patients/year to treat with the same budget.

Conclusions The implementation of dose modification strategies with biological therapies is considered to be an innovative tool that maintains treatment goals using the minimum effective dose for those selected patients. The consequences of an adequate treatment strategy directed to keep long-term clinical response in our patients could be both the reduction of the treatment costs and that of the drug exposure. The Psoriatic Arthritis Units permits this new point of view to control the patients and their treatments.

1. Luelmo J, Gratacόs J, Moreno Martínez-Losa M, Ribera M, Romanía J, Calvet J et al. A report of 4 years of experience of a Multidisciplinary unit of Psoriasis and psoriatic arthritis. Reumatol Clin.2014;10:141–6 - Vol. 10 Núm.3

Disclosure of Interest None declared