Background and importance The optimisation strategies are based on dose reduction or incresing the dosing interval. In this way, patients have fewer adverse effects, more adherence and the same benefit.

Aim and objectives To analyse the optimisation of subcutaneous biological therapies (BT) by the Rheumatology and Dermatology Services, as well as evaluating the cost avoided, in a third-level hospital.

Material and methods Retrospective observational study of patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic arthritis (PsA) and plaque psoriasis, in treatment with biological drugs and optimisation dosage, during the year 2020. The evaluation of the cost avoided was the difference between the cost with the usual dosage and optimisation dosage. Variables: sex, previous BT, year of initiation with BT, current BT (biosimilar/reference), dosage, drug cost. Information was collected from the hospital’s information systems.

Results 95 patients were included with BT optimisation: 38% with RA, 27% with AD, 22% with PsA and 13% with psoriasis. 100% of patients were on the therapeutic target for at least 6 months and the reduction of doses between 20% and 50% spacing the administration interval. 43% of the patients were women, and 57% men. 81% had not had another previous biological and 77% had the same biological drug ≥4 years. The optimised BT were: tumour necrosis factor alpha antagonists (anti-TNFα drugs): adalimumab (47%), etanercept (40%) and certolizumab (5%); anti-interleukin (IL) 6: tocilizumab (1%); anti-IL17A: ixekizumab (3%) and secukinumab (1%); anti-IL23: guselkumab (1%); anti-IL12–23: ustekinumab (2%). The most common intervals were: 21% adalimumab every 21 days, followed by 17% with etanercept every 21 days. The use of biosimilars versus the reference drugs of adalimumab and etanercept was: 29%/71% and 68%/32%, respectively.

The costs avoided were: Rheumatology: €216 968.29. With the usual dose, it would have meant an annual cost of: €405 381.08 and with optimised: €188 412.79; Dermatology: €18 670.02. With the usual dose it would have cost €43 362.38 and with the optimisation: €24 692.36.

Conclusion and relevance The optimisation of biological therapies has managed to keep our patients in therapeutic objective. Optimisation is a beneficial strategy for the patient and for our health system, since we obtain significant savings in effects adverse effects and costs of therapy.

Conflict of interest No conflict of interest