The Age Factor in Ixekizumab Survival: Older Patients Show Higher Long-Term Treatment Survival

Background and Objectives: Ixekizumab is a human monoclonal antibody targeting interleukin-17A, approved for the treatment of moderate-to-severe plaque psoriasis. Given its demonstrated efficacy and safety in clinical trials, this study aimed to evaluate the real-world drug survival of Ixekizumab and identify clinical predictors of treatment discontinuation. Materials and Methods: A retrospective, observational, hospital-based study was conducted in the Department of Dermatology at the Central University Hospital of Asturias (HUCA). Patients with moderate-to-severe plaque psoriasis who initiated treatment with Ixekizumab (Taltz^®) between 8 June 2017 and 10 October 2024, were included. Demographic data, comorbidities, age at disease onset, family history, PASI score, and previous treatments were recorded. Drug survival was assessed using Kaplan-Meier survival curves and the log-rank test. Predictors of discontinuation were analyzed using univariate and multivariate Cox proportional hazards models. Results: A total of 103 patients (55.3% women) were included. Drug survival rates were 85% at one year, 73% at two years, and 61% at four years, with a mean treatment duration of 52.5 months (95% CI: 46.01-58.99). Multivariate analysis showed that patients under the age of 65 had a significantly higher risk of treatment discontinuation (hazard ratio: 1.813; p < 0.05). The most common reason for discontinuation was secondary treatment failure (45.16%). Ixekizumab demonstrated sustained drug survival in a real-world setting, with rates falling within the mid-to-upper range reported in the literature. Older age (>65 years) was associated with greater treatment persistence, highlighting a potential influence of age on long-term therapeutic adherence.