The majority of psoriatic arthritis (PsA) patients experience a good clinical response to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and biologic therapies (bDMARDs). However, treatment failure with these drugs can represent a relevant clinical problem. Moreover, in daily clinical practice, the appropriate identification of patients eligible for these agents can be conditioned by numerous aspects, mainly represented by comorbidities, such as history of malignancies, chronic and recurrent infectious diseases. Areas covered: We searched in the PUBMED database and review published data on the efficacy and safety profile of the small molecules, inhibitor of phosphodiesterase 4, apremilast, and of JAK/STAT pathways, tofacitinib, in PsA. Moreover, we report data on the other JAK inhibitor, baricitinib, and the A(3) adenosine receptors agonist, CF101, emerging by studies conducted in psoriasis patients. Expert opinion: In Psoriatic Arthritis, apremilast appears promising for PsA and recent studies have shown a good efficacy and an acceptable safety profile. Data on tofacitinib in PsA are limited. Studies on the small molecules, baricitinib and CF101 are still incomplete and limited to trials conducted in Rheumatoid Arthritis and in psoriasis. Further studies on small molecules and on their underlining mechanisms are advocated in PsA.
Keywords: JAK; PDE4; Psoriatic arthritis; apremilast; cAMP; tofacitinib.