Abstract
Generalized pustular psoriasis (GPP) is a potentially life-threatening skin disease. Although several medications are approved for treating GPP in Japan, there are limited data on real-world treatment patterns or drug survival (the number of prescribed days of treatment). This retrospective cohort study describes drug survival and treatment patterns of patients with newly diagnosed GPP (International Classification of Diseases, 10th Revision code L40.1), and ≥1 year of follow-up, using de-identified claims data (Medical Data Vision Co., Ltd.) from January 2016 to August 2021. Most (97.0%) of the 434 Japanese patients received first-line therapy of etretinate (26.4%), topical medications (14.7%), or cyclosporin (14.3%); 80.0% and 60.1% of patients received a second and third line of therapy (LOT), respectively. Use of etretinate (12.6%) and cyclosporin (5.9%) decreased in second-line therapies, whereas use of biologics (interleukin [IL]-17, 14.3%; IL-23 inhibitors, 7.6%) and topical medications (22.1%) increased or remained consistent. Approximately 50% of biologics were prescribed in combination with systemic medications or systemic corticosteroids. Median (range) time to next therapy (TTNT) was 2.8 (0.03-48.07) months for first-line therapy and 3.3 (0.03-52.97) months for all other LOTs. TTNT was longer for combination therapies (up to 16.5 months) compared with monotherapies (up to 7.5 months). Biologics exhibited longer drug survival with fewer treatment episodes compared with non-biologic systemic medications. Among frequently used therapies, the median (95% confidence interval) drug survival was 8.8 (5.8-11.8) months for etretinate, 4.3 (2.2-6.9) months for systemic corticosteroids, and 19.6 (16.1-26.7) months for secukinumab. Treatment patterns varied considerably, highlighting the need for treatment algorithms and effective, well-tolerated medications to support patients to help them remain on long-term therapy.