Background Psoriasis is a chronic immune-mediated inflammatory skin disease which can also involve joints. It is often associated with burdensome comorbidities which negatively impact prognosis and quality of life (QoL). Biologic agents have been shown to be effective in controlling disease progression, but their use is associated with higher costs compared with traditional systemic treatments. The economic analysis of the CANOVA (EffeCtiveness of biologic treAtmeNts for plaque psOriasis in Italy: an obserVAtional longitudinal study of real-life clinical practice) study aims to assess the costs and cost-effectiveness of biologics in a real-world context in Italy. Methods The annualised overall direct costs of moderate-to-severe plaque psoriasis management, the annualised cost of biologic drugs and the cost per responder in the Italian National Health System perspective were assessed. More specifically, the cost per response and cost per sustained response of the most prescribed biologic therapies for the treatment of moderate-to-severe plaque psoriasis within the CANOVA study were assessed using the Psoriasis Area Severity Index (PASI) at several score levels (75, 90 and 100%). Results The most frequently used biologic therapies for plaque psoriasis were secukinumab, ustekinumab, adalimumab originator, and ixekizumab. Cost of biologics was the driver of expenditure, accounting for about 98% of total costs. Adalimumab originator was the biologic with the lowest cost per responder ratio (range: €7848 - €31,378), followed by secukinumab (range: €9015 - €33,419). Ustekinumab (range: €11,689 – €39,280) and ixekizumab (range: €11,092 – €34,289) ranked respectively third and fourth, in terms of cost-effectiveness ratio. As concerns the cost per sustained response analysis, secukinumab showed the lowest value observed (€21,375) over the other options, because of its high response rate (86% vs. 60–80%), which was achieved early in time. Conclusion Biologic therapy is a valuable asset for the treatment of moderate-to-severe plaque psoriasis. Concomitant assessment of treatment costs against the expected therapeutic response over time can provide physicians and payers additional insights which can complement the traditional risk-benefit profile assessment and drive treatment decisions. Supplementary Information The online version contains supplementary material available at 10.1186/s12913-021-06866-7.