Supplementary Material for: Dupilumab for chronic prurigo: case series on effectiveness, safety, and quality of life

Background Chronic prurigo (CPG) is a pruritic skin disease, characterized by an itch–scratch cycle and scarring. It reduces patients’ quality of life (QoL). Dupilumab is a monoclonal human IgG antibody that inhibits signaling of the interleukin 4 (IL-4) and interleukin 13 (IL-13) pathways through blockade of the IL-4 receptor (IL-4R). Patients with CPG who receive dupilumab often report great improvement in itch and overall QoL. We therefore reviewed our experience in order to follow up on QoL, safety, and treatment response in patients with CPG who received dupilumab. Methods We conducted a real-world retrospective single-center case series. Outcomes were assessed by phone interviews and photographs using validated questionnaires and scores. Demographic data were obtained from the hospital files. Follow-up was up to 2 years. We assessed quality of life with the Dermatology Life Quality Index (DLQI) and the Itchy quality of life questionnaire (ItchyQoL). Numerical Rating Scale (NRS) was used to assess itch. Prurigo lesions were documented with the Prurigo activity and severity score (PAS). Results Ten patients were included in this study. Results were reported up to two years after treatment with dupilumab. The response variables for DLQI, ItchyQoL, NRS and PAS analyses showed a statistically significant decrease over time (DLQI: (p = < 0.0001, [-0.84; -1.27]), ItchyQoL: (p = < 0.0001, [-9.89; -18.69], NRS maximum and average: p = < 0.0001, [-0.52; -0.86] and p = < 0.0001; [-0.55; -0.94] and PAS number of lesions: p = 0.0005; [-1.70; -5.28]). The percent decrease after one year of treatment (this estimate is based on model estimates) ranges from -42% to -82%. Four (40%) patients reported mild side effects. No serious side effects were reported. Conclusion Dupilumab treatment of CGP for up to two years is associated with improved QoL and less itching.