Efficacy of Bimekizumab on Palmoplantar Psoriasis: A 16-Week Multicenter Retrospective Study—IL PSO (Italian Landscape PSOriasis)

Background/Objectives: Palmoplantar psoriasis (PP) is a challenging variant of psoriasis that affects high-impact areas such as palms and soles and significantly impairs quality of life despite often limited body surface involvement. Conventional topical and systemic therapies may be insufficient, and evidence on biologic treatments for this specific phenotype remains limited. Bimekizumab (BKZ), a monoclonal antibody targeting IL-17A and IL-17F, has shown high efficacy in plaque psoriasis. This study aimed to evaluate the real-world effectiveness and rapidity of action of BKZ in patients with palmoplantar psoriasis compared with patients with psoriasis vulgaris (PV). Methods: We conducted a multicenter retrospective cohort study using data from 22 Italian dermatological units within the IL-PSO (Italian Landscape-Psoriasis) database. Adult patients treated with BKZ between November 2022 and October 2024 were included and categorized into three groups: isolated PP, PP associated with PV (PP + PV), and PV without palmoplantar involvement. Clinical outcomes included the Psoriasis Area and Severity Index (PASI), Dermatology Life Quality Index (DLQI), and pruritus Visual Analogue Scale (VAS). Outcomes were assessed at baseline, week 4, and week 16. Results: A total of 47 patients were included. The baseline PASI was lower in the PP group compared with the PP + PV and PV groups, whereas the DLQI was highest in patients with isolated PP. Rapid clinical improvement was observed in all groups. The mean % PASI reduction at week 4 was 60.5%, 65.1%, and 77.0% in the PP, PP + PV, and PV groups, respectively, increasing to 94.8%, 90.4%, and 91.8% at week 16. The proportion of patients achieving complete clearance (PASI = 0) at week 16 was 73.3% (11/15), 68.2% (15/22), and 70.0% (7/10), respectively. Significant improvements were also observed in DLQI and pruritus scores over time. No significant safety concerns emerged. Conclusions: In this real-world multicenter cohort, bimekizumab demonstrated rapid and high efficacy in patients with palmoplantar psoriasis, both isolated and associated with psoriasis vulgaris. These findings support the use of BKZ as an effective therapeutic option for psoriasis involving high-impact areas, as the palmoplantar, although larger studies are needed to confirm these results.