This letter to the editor addresses the treatment challenges for psoriasis patients resistant to multiple biological therapies, proposing categorizing those failing to respond to at least four biologics as multi-resistant. Based on their experience with 10 such patients at the Dermatologic Clinic of the University of Turin, the authors note significant improvement with the IL-23 inhibitor risankizumab. Three out of six patients achieved a 100% improvement in Psoriasis Area and Severity Index (PASI) score at 16 weeks, despite comorbidities and difficult-to-treat psoriasis variants.

Highlighting the scarcity of data on patients who are multi-resistant, the authors stress the need for further research to understand this population better and identify predictive factors for treatment failure. They discuss potential factors like smoking, body mass index, and gender but note the limited statistical significance due to the small sample size. While recognizing the challenge these patients pose to clinicians, the authors underscore the promising role of modern IL-23 inhibitors. They advocate for more research to establish guidelines for therapeutic strategies and switches between different classes of biological drugs.

Reference: Mastorino L, Roccuzzo G, Dapavo P, et al. Patients with psoriasis resistant to multiple biological therapies: characteristics and definition of a difficult-to-treat population. Br J Dermatol. 2022;187(2):263-265. doi: 10.1111/bjd.21048. Epub 2022 May 24. Erratum in: Br J Dermatol. 2022;187(6):1083.