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.