The Static Physician’s Global Assessment of Genitalia: A Clinical Outcome Measure for the Severity of Genital Psoriasis

August 2017 | Volume 16 | Issue 8 | Original Article | 793 | Copyright © August 2017

Joseph F. Merola MD MMSc,a Alison Potts Bleakman PhD,b Alice B. Gottlieb MD PhD,c Alan Menter MD,d April N. Naegeli PhD,b Robert Bissonnette MD MS FAAD FRCPC,e Lyn Guenther MD FRCPC,f John Sullivan MBBS MS,g Kim Meeuwis MD PhD,h Kyoungah See PhD,b and Kristina Callis Duffin MD MSi

aDepartment of Dermatology and Medicine, Division of Rheumatology, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA, USA bEli Lilly and Company, Indianapolis, IN, USA cDepartment of Dermatology, New York Medical College at Metropolitan Hospital, New York, NY, USA dDepartment of Dermatology, Baylor University Medical Center, Dallas, TX, USA eInnovaderm Research, Montreal, QC, Canada fThe Guenther Dermatology Research Centre, London, ON, Canada gDepartment of Medicine, UNSW, Sydney, New South Wales, Australia hDepartment of Dermatology, Radboud University Medical Center, Nijmegen, The Netherlands iDepartment of Dermatology, University of Utah, Salt Lake City, UT, USA

in its development, and to determine its reliability by analyzing assessment scores from clinicians involved in evaluating photographs of patients with genital psoriasis.

MATERIALS AND METHODS

sPGA-G Development and Assessment Instructions

An advisory group of five global experts on genital psoriasis was formed in collaboration with Eli Lilly and Company to develop the sPGA-G for the assessment of genital psoriasis in clinical trials. Advisor input was incorporated into the design of the scale, the assessment instructions, and the associated training and clinical certification materials based on their clinical experience in treating patients with genital psoriasis. The sPGA-G is a 6-point numerical scale ranging from 0 (clear) to 5 (very severe) to assess genital psoriasis severity at a given time point (Table 1). In order to ensure consistency between assessments in clinical trials, the sPGA-G assessment area was precisely defined using guidance from the advisors and in consideration of the areas defined in the modified Genital Psoriasis Area and Severity Index (mGPASI).5,15 The assessment area includes the vulvar region from the clitoral prepuce to the perineum, including the labia majora, labia minora, and perineum for females, and the penis, scrotum, and perineum for males. The sPGA-G assessment does not include the pubis, inguinal folds, peri-anal region, or the gluteal cleft. Consistent with other sPGA scales used in clinical trials for the assessment of plaque psoriasis, the sPGA-G evaluates three clinical features of genital psoriatic lesions: erythema, plaque elevation, and scale. Not all three individual features are always present on evaluation, especially the latter two. Thus, while the overall score represents a combination of all three features, it should primarily be determined by the degree of erythema, as erythema is the dominant feature in the majority of cases of genital psoriasis.3,7,13 Erythema descriptions distinguish each severity level. A score of 0 (clear) represents the absence of erythema with or with- out residual post-inflammatory hyper- or hypo-pigmentation. The descriptions and associated scores for erythema are: (1) light pink (minimal), (2) pink to light red (mild), (3) definite red (moderate), (4) bright red (severe), and (5) extreme, deep red (very severe). The severity of elevation is determined by plaque thickness relative to the surrounding skin (eg, indistinct, slight, or marked elevation) together with the sharpness of plaque edges (eg, indistinct, sloped, or hard and sharp edges). Scaling severity is determined by the extensiveness of scale (eg, scale absent or present on some, most, or all plaques) plus scale roughness and adherence (eg, fine, coarse and non-adherent, or coarse and adherent scale). The sPGA-G was reviewed and approved by the advisory group and additional experts on genital psoriasis and clinical outcome measures. Additional review was conducted by Eli Lilly and Company employees specializing in developing clinical outcomes measures for use in evaluating treatment bene t in clinical trials in accordance with FDA guidelines.

Patient Photographs

Photographs of suspected cases of genital psoriasis were obtained from dermnetnz.org, VisualDx, ScienceSource, and a dermatologist experienced with genital psoriasis diagnosis. All patients provided written informed consent and all photographs were de-identified. Photographs were reviewed and selected by an academic dermatologist (JFM) with extensiveTable 1