Abstract
INTRODUCTION: Dermatomyositis (DM) is a rare systemic autoimmune disease characterized by a distinctive debilitating skin rash and skeletal muscle weakness. It is unclear if existing clinical outcome assessment (COA) measures include the concepts of priority to patients and those necessary to fully capture improvements in the active cutaneous manifestations of DM. This study aimed to develop the Cutaneous Dermatomyositis Investigator Global Assessment (CDM-IGA), a de novo IGA, for use in clinical trials of adult DM. METHODS: Eight DM clinical experts participated in 60-min qualitative interviews consisting of concept elicitation and cognitive debriefing methodologies. Concept elicitation comprised open-ended questions with follow-up probes to explore clinicians' experiences of treating patients with DM, the impact of symptoms on patients' quality of life, and the severity levels of disease characteristics to explore DM progression. Cognitive debriefing required the clinical experts to perform a review of the CDM-IGA, designed to assess the severity of cutaneous disease activity of DM. After the interviews, a consensus meeting with three clinical experts was held to agree on any outstanding issues relating to the CDM-IGA. RESULTS: The CDM-IGA was iteratively developed using the opinions of nine clinical experts. Feedback provided by all clinicians agreed that erythema was the main active cutaneous manifestation of DM and should be the primary characteristic on the CDM-IGA, split by erythema color and extent. To determine cutaneous disease severity, experts suggested adding a metric called secondary changes, which combined erosion/ulceration and lichenification, which could modify the patient's final score. Three clinical experts suggested that a photo-guide to support assessments of erythema across different skin tones could be beneficial. CONCLUSIONS: A novel CDM-IGA was developed for use with adult patients with DM in clinical trials, based on an iterative development process that combined qualitative feedback from clinical experts of DM and importantly adult patients living with DM.