Monotherapy or combination therapy in PsA: current aspects

Psoriatic arthritis (PsA) is an immune-mediated inflammatory disease with heterogeneity regarding its clinical features, mainly affecting the skin and the musculoskeletal system; additionally, extra-musculoskeletal manifestations and comorbidities are common, adding complexity to its treatment. In the last decades, a plethora of therapeutic options have been available, including conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs), biological DMARDs (bDMARDs), and targeted synthetic DMARDs (tsDMARDs), and many recommendations have been published regarding the proper use of them in patients with PsA. In rheumatoid arthritis, the combination of conventional with bDMARDs or tsDMARDs is a common and recommended practice, whereas in PsA there is scarce data about the benefit of this combination. This review summarizes all the available data from randomized clinical trials, observational studies, and registries about the value of this therapeutic strategy. Use of b/tsDMARDs in PsA: with or without csDMARDsOver the last years, many different b/ts DMARDs have been porven to be efficacious in psoriatic arthritis (PsA). Although in rheumatoid arthritis, it is established that most of these drugs work better in combination with conventional synthetic DMARDs (e.g methotrexate), this seems to be slightly different in PsA. Herein, we review the current literature about the combination therapy versus monotherapy of b/ts DMARDs in PsA. We present the results of this narrative review in a structured (per drug category) way, so that it is easier for the reader to find relevant information. There is no doubt that the currently available treatment options in PsA have changed the course of the disease and improved the functional status of the patients. However, as there is still a substantial proportion of patients who do not achieve remission or low disease activity, the need to find effective therapeutic regimens or follow different strategies is growing. In this direction, the combination of a conventional synthetic with biological or targeted synthetic DMARD does not seem to be more effective than the monotherapy of the latter. This seems to be more pronounced in the newer drug categories (anti-IL-17, anti-IL23 and JAKi) compared to the TNFi, where the co-administration of a csDMARD improves their survival.