Time to Relapse After Discontinuing Systemic Treatment for Psoriasis: A Systematic Review.

Background: The decision of when to discontinue systemic treatment after achieving remission in psoriasis is an important question. In this systematic review, we sought to evaluate time to relapse after the discontinuation of systemic treatment in psoriasis patients.

Methods: Systematic searches of PubMed, Cochrane Library, and Embase databases were performed for randomized controlled studies reporting time to relapse after discontinuation of systemic drugs in psoriasis patients. In addition, pharmaceutical companies were contacted by the authors regarding missing data from the identified publications. In each publication, the time to psoriasis relapse and the timing of drug discontinuation were carefully assessed. The level of psoriasis control at the time of drug discontinuation and the definition used for psoriasis relapse were taken into account.

Results: Thirty articles published before April 2021 were included in the systematic review. Four articles focused on conventional systemic treatments with methotrexate and/or cyclosporine, nine focused on tumor necrosis factor (TNF) antagonists, eight focused on interleukin-17 (IL-17) antagonists, eight focused on IL-12/23 or IL-23 antagonists, and one focused on tofacitinib and apremilast. Different definitions were used to define psoriasis treatment success at the time of drug discontinuation. Similarly, heterogeneous criteria were used to define psoriasis relapse. Comparison between drugs was performed indirectly (i.e. across studies) for most drugs. Considering time of 50% loss of maximum Psoriasis Area Severity Index (PASI) improvement, a shorter median time to psoriasis relapse was observed with traditional systemic treatment (~ 4 weeks) compared to biological agents (from 12 to ~ 34 weeks). When using stringent relapse criteria, such as loss of PASI 90, a longer time to relapse after treatment cessation was observed with IL-23 antagonists (21-42 weeks) versus IL-17 antagonists (7-24 weeks).

Conclusion: Biological agents are associated with a longer time to relapse than oral systemic agents after drug discontinuation. Among biologicals, IL-23 antagonists are associated with the longest time to relapse. These findings may have clinical consequences for the selection of systemic agents when intermittent treatment is necessary.