GPP OBSERVE: Real-world clinical characteristics and treatment patterns among patients with generalized pustular psoriasis in the United States

Introduction: Generalized pustular psoriasis (GPP) is a chronic autoinflammatory skin disease characterized by unpredictable and potentially life-threatening flares of widespread erythema and sterile pustules that may be accompanied by systemic inflammation, as well as persistent symptoms between flares. Although GPP may co-occur with plaque psoriasis (PsO), it is a distinct clinical disease driven predominantly by IL-36 pathway dysregulation, whereas plaque PsO is primarily associated with the IL-23/IL-17 inflammatory pathways. Spesolimab specifically targets the IL-36 pathway and is currently the only US Food and Drug Administration (FDA)-approved treatment for GPP. Real-world data detailing the treatment of patients with GPP is currently limited. To address this gap, we describe patient characteristics, health care resource utilization (HCRU), and treatment patterns among patients with GPP in the US. Methods: This observational cohort study analyzed retrospective data from the OM1 Real-World Data Cloud among individuals who had ≥1 GPP diagnosis from January 1, 2013 to September 13, 2024. Inclusion in this analysis required linked medical claims and electronic medical records (EMR) data within 180 days following GPP diagnosis and ≥1 healthcare encounter beyond the 180-day period. Individual patient data including treatment and disease history, laboratory results, and GPP disease characteristics were collected from the EMR data. Inclusion in the annual HCRU analysis required data within 12 months following diagnosis and ≥1 healthcare encounter beyond 12 months. Descriptive statistics were used in this study. Results: A total of 10,313 patients with GPP were included in the study. Most patients were female (64.6%) and White (87.5%), with a mean age of 55.3 (SD: 18.0) years. Approximately one-third (31.9%) of patients had comorbid plaque PsO and the mean Charlson Comorbidity Index among patients (n=10,304) was 1.4 (SD: 2.0). Among patients with available assessments, 21.5% (185/859) had ≥20% affected body surface area, and 41.3% (33/80) had moderate-to-severe disease severity based on the GPP Physician Global Assessment. During the 12-month follow-up period after GPP diagnosis, 12.4% (1,244/10,026) of patients experienced all-cause hospitalization, and 1.2% (119/10,026) experienced GPP-related hospitalization, with median (IQR) lengths of stay of 6.0 (3.0-12.0) and 5.0 (4.0-9.5) days, respectively. All-cause and GPP-related emergency department visits occurred in 21.3% (2,132/10,026) and 1.6% (162/10,026) of patients, respectively. Overall, the most commonly used GPP-related treatments were topical corticosteroids (40.2%), oral corticosteroids (13.6%), and non-GPP–specific biologics (13.2%). During the period following FDA approval of intravenous spesolimab (September 2022 to September 2024; n=566), utilization of spesolimab remained limited (1.9%) and was lower than that of several non-GPP‒specific biologics, including secukinumab (5.7%), risankizumab (4.2%), adalimumab (3.5%), infliximab (2.5%), and guselkumab (2.3%). Conclusion: These findings suggest persistent unmet needs in GPP management, reflected by continued use of non-GPP‒specific therapies and high HCRU, and highlight the potential value of broader adoption of targeted, GPP-specific treatments to reduce disease burden. Future real-world studies are needed to examine long-term shifts in treatment patterns and clinical outcomes that may emerge from the introduction of GPP-specific therapies.