Project description:Risankizumab, a humanized monoclonal antibody that targets interleukin-23 p19 subunit, was developed for the treatment of psoriasis. This work characterizes risankizumab pharmacokinetics in Japanese and Chinese healthy subjects compared with white healthy subjects and in Japanese patients with moderate to severe plaque psoriasis, generalized pustular psoriasis, or erythrodermic psoriasis. A phase 1, single-dose study evaluated risankizumab pharmacokinetics and safety/tolerability in healthy white (18 and 300 mg subcutaneous [SC]), Japanese (18, 90, and 300 mg SC and 200, 600, and 1200 mg intravenous [IV]), and Chinese (18, 90, and 300 mg SC) subjects; pharmacokinetic data were analyzed using noncompartmental methods. Risankizumab pharmacokinetic data from phase 2/3 studies in Japanese patients with plaque psoriasis, generalized pustular psoriasis, or erythrodermic psoriasis following multiple SC doses of 75 mg or 150 mg were analyzed using a population pharmacokinetic approach along with data from the phase 1 and global phase 1 to 3 studies. Risankizumab plasma exposures (peak plasma concentration and area under the concentration-time curve) were approximately dose-proportional across 18- to 300-mg SC or 200- to 1200-mg IV doses. Risankizumab terminal elimination half-life (harmonic mean 27-34 days) was comparable across doses and ethnicities. Risankizumab exposures were approximately 20% to 30% higher in Japanese and Chinese healthy subjects compared with white healthy subjects or in Japanese patients compared with non-Japanese patients. After accounting for body-weight differences, risankizumab exposures were comparable across ethnicities. Overall, there was no ethnic impact on risankizumab pharmacokinetics, and the small difference in exposure due to body weight has no clinical relevance.
Project description:Generalized pustular psoriasis (GPP) is a rare, debilitating, and often life-threatening inflammatory disease characterized by episodic infiltration of neutrophils into the skin, pustule development, and systemic inflammation, which can manifest in the presence or absence of chronic plaque psoriasis (PV). Current treatments are unsatisfactory thus a better understanding the pathogenesis of GPP is warranted. To assess the pathophysiological differences between GPP and PV we performed a gene expression study on formalin-fixed paraffin-embedded biopsies of GPP (n=30) and PV (n=12) lesions and healthy control (n=20) skin. Compared with healthy skin, GPP lesions yielded 365 and PV 898 differentially expressed genes respectively, with 190 upregulated in both diseases. We detected higher expression of IL-1 and IL-36 cytokines in GPP lesions compared with PV, and this occurred proximal to neutrophils. We show both activated neutrophils and isolated neutrophil proteases can activate IL-36. Diverging from the Th1/Th17 pathophysiology of PV, significantly fewer IL23A, IL17A, IFNG, CXCL9, CXCL10 and MX1 transcripts were detected in GPP lesions. Our data indicate a level of sustained activation of IL-1 and IL-36 in GPP, inducing neutrophil chemokine expression, infiltration and pustule formation, suggesting that the IL-1 and IL-36 inflammatory axes are the main drivers of disease pathology in GPP.
Project description:Psoriasis is a chronic inflammatory skin condition that has a fairly wide range of clinical presentations. Plaque psoriasis, which is the most common manifestation of psoriasis, is located on one end of the spectrum, dominated by adaptive immune responses, whereas the rarer pustular psoriasis lies on the opposite end, dominated by innate and autoinflammatory immune responses. In recent years, genetic studies have identified six genetic variants that predispose to pustular psoriasis, and these have highlighted the role of IL-36 cytokines as central to pustular psoriasis pathogenesis. In this review, we discuss the presentation and clinical subtypes of pustular psoriasis, contribution of genetic predisposing variants, critical role of the IL-36 family of cytokines in disease pathophysiology, and treatment perspectives for pustular psoriasis. We further outline the application of appropriate mouse models for the study of pustular psoriasis and address the outstanding questions and issues related to our understanding of the mechanisms involved in pustular psoriasis.
Project description:Generalized pustular psoriasis (GPP) is a rare, severe form of pustular psoriasis characterized by widespread, recurrent episodes of neutrophil-rich pustule formation in the epidermis, which can be accompanied by fever and systemic inflammation. Recent clinical, histologic, and genetic evidence indicates that GPP is a distinct entity from plaque psoriasis, with different cytokine pathways predominant in the manifestation of each disease. The interleukin-36 (IL-36) signaling cascade plays a key role in regulating the innate immune system, and its dysregulation appears central to the pathogenesis of GPP. The altered expression of various IL-36 pathway constituents has been shown to cause a positive feedback loop of uncontrolled signaling and excess production of inflammatory cytokines, which in turn leads to chemokine induction and neutrophil recruitment in the epidermis. Given the potentially life-threatening nature of GPP episodes, drug interventions that rapidly achieve disease resolution are required. Early phase data indicate that treatments targeting various components of the IL-36 inflammatory cascade represent promising areas of research. However, there are currently no therapeutic agents specifically approved for GPP in the USA or Europe. Understanding the inflammatory pathways, associated risk factors, and role of neutrophils in the manifestation and perpetuation of GPP flares remains a key goal in developing effective therapeutics. In this article, we summarize the current understanding of GPP, describe novel therapeutic opportunities, and detail how the unique pathophysiology of the disease may inform future treatment strategies.
