Background: Real-world data evaluating effectiveness and persistence of systemic therapies for patients with psoriasis are limited. Objectives To determine the effectiveness and persistence of acitretin, ciclosporin, fumaric acid esters (FAEs) and methotrexate in patients with moderate-to-severe psoriasis., Methods: Data from the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR), a prospective, multicentre pharmacovigilance register of patients with moderate-to-severe psoriasis receiving biologic and/or conventional systemic therapies, were analysed. Eligible patients were ≥ 16 years of age receiving a first course of acitretin, ciclosporin, FAEs or methotrexate between 2007 and 2021 with ≥ 6 months' follow-up. Effectiveness was defined as achieving absolute Psoriasis Area and Severity Index (aPASI) ≤ 2 reported ≥ 4 weeks after treatment start date until date of cessation. To identify baseline clinical variables associated with treatment effectiveness, we used multivariable logistic regression models estimating the adjusted odds ratio (aOR) of achieving aPASI ≤ 2. To describe drug persistence associated with ineffectiveness, occurrence of adverse events or other reasons for discontinuation, survival estimates with 95% confidence intervals (CIs) were obtained using a flexible parametric model. Results were obtained using multiple imputed data., Results: In total, 5430 patients were included in the analysis. Overall, 1023 (19%) patients were receiving acitretin, 1401 (26%) patients were on ciclosporin, 347 (6%) patients were on FAEs, and 2659 (49%) patients were receiving methotrexate at registration. The proportion of patients who achieved aPASI ≤ 2 was lower for those treated with acitretin [n = 118 (21%)] compared with those receiving ciclosporin [n = 233 (34%)], FAEs [n = 43 (29%)] and methotrexate [n = 372 (32%)]. Factors associated with ineffectiveness included prior experience to previous nonbiologic systemic therapies (acitretin) (aOR 0.64, 95% CI 0.42-0.96), male sex (methotrexate) (aOR 0.58, 95% CI 0.46-0.74), comorbidities (aOR 0.70, 95% CI 0.51-0.97) and alcohol consumption (≤ 14 units per week) (ciclosporin) (aOR 0.70, 95% CI 0.50-0.98). Persistence associated with all reasons for discontinuation showed better survival for methotrexate compared with acitretin, ciclosporin and FAEs cohorts at 12 months [survival estimate 46.1 (95% CI 44.0-48.3), 31.9 (95% CI 29.4-34.7), 30.0 (95% CI 27.5-32.4) and 35.0 (95% CI 29.9-40.9), respectively]., Conclusions: The real-world effectiveness and persistence of acitretin, ciclosporin, FAEs and methotrexate were generally low. Previous nonbiologic systemic therapies, male sex, comorbidities and alcohol consumption were risk factors associated with treatment ineffectiveness., Competing Interests: Conflicts of interest P.J.H. has received educational grants, consultancy fees and research funding from Janssen, AbbVie, Eli Lilly and LEO Pharma. P.M.L. has received honoraria and/or grants as an investigator, speaker, and/or acted as an advisory board member for AbbVie, Almirall, Amgen, Celgene, Janssen Cilag, Eli Lilly, Pfizer, Sanofi, LEO, UCB Pharma and Novartis. N.J.R. has received travel support, research grants (Newcastle University) and income to Newcastle University for advisory boards/lectures from AbbVie, Almirall, Celgene, Boehringer Ingelheim, Janssen Cilag, Novartis and UCB Pharma. A.B. has received travel bursaries and performed ad hoc consultancy and lecturing roles with AbbVie, Almirall, Galderma, Eli Lilly, Janssen, LEO Pharma, Novartis, UCB Pharma, Pfizer, BMS, MSD and Sanofi. R.B.W. has acted as a consultant and/or speaker for and/or received research grants from AbbVie, Amgen, Almirall, Celgene, Eli Lilly, Pfizer, LEO Pharma, Novartis, Janssen Cilag, Medac, UCB Pharma and Xenoport. C.H.S. reports grants from a Medical Research Council-funded stratified medicine consortium with multiple industry partners, grants from an Innovative Medicines Initiative (Horizon 2020)-funded European consortium with multiple industry partners, and other grants from AbbVie, Novartis, Pfizer, Sanofi, Boehringer Ingelheim and Sobi, outside the submitted work; she is also chair of UK guidelines on biologic therapy in psoriasis. C.E.M.G. has received honoraria and/or research grants from AbbVie, Almirall, Amgen, AnaptysBo, Bristol Myers Squibb, Celgene, Galderma, LEO Pharma, Eli Lilly, GSK-Stiefel, Janssen Cilag, MSD, Novartis, Pfizer, Sandoz and UCB Pharma., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists.)