Psychometric Evaluation of the Facial and Total Vitiligo Area Scoring Index Instruments in the TRuE-V Phase 3 Studies.

ABSTRACT

INTRODUCTION: This study reports psychometric testing of the facial and total Vitiligo Area Scoring Index quantitative clinical instruments (F-VASI [range 0-3], T-VASI [range 0-100], respectively) using data from two phase 3 randomized, vehicle-controlled studies of ruxolitinib cream (TRuE-V1/TRuE-V2), the largest vitiligo trials conducted to date. Because VASI assessment is required by regulatory authorities, we evaluated the psychometric properties of the VASI instruments and confirmed thresholds for clinically meaningful change. METHODS: The TRuE-V1/TRuE-V2 full analysis set population included 652 patients (≥ 12 years old with nonsegmental vitiligo affecting ≤ 10% total body surface area, F-VASI ≥ 0.5, and T-VASI ≥ 3 at baseline). Data collected using the facial and total Patient Global Impression of Change-Vitiligo (PaGIC-V) and Physician's Global Vitiligo Assessment (PhGVA) scales were used as anchors to assess F-VASI and T-VASI for reliability, validity, sensitivity to change, and clinically meaningful change. RESULTS: Median F-VASI and T-VASI scores were 0.70 and 6.76, respectively, at baseline, decreasing to 0.48 and 4.80 at week 24. Test-retest reliability was excellent between screening and baseline for F-VASI (intraclass correlation coefficient [ICC] 0.943) and T-VASI (ICC 0.945). Among stable patients per PaGIC-V and PhGVA, reliability was moderate to good for both F-VASI (ICC 0.891 and 0.739, respectively) and T-VASI (ICC 0.768 and 0.686). F-VASI and T-VASI differentiated well among PhGVA categories mild/moderate/severe at baseline and week 24. Both VASI instruments detected changes assessed by correlations with PaGIC-V scores at week 24 (F-VASI, r = 0.610; T-VASI, r = 0.512) and changes in PhGVA scores from baseline to week 24 (F-VASI, r = 0.501; T-VASI, r = 0.344). Thresholds for clinically meaningful improvement per PaGIC-V and PhGVA were 0.38-0.60 for F-VASI and 1.69-3.88 for T-VASI. CONCLUSIONS: Data from the TRuE-V1/TRuE-V2 studies confirmed that F-VASI and T-VASI are reliable, valid, and responsive to change, with defined clinically meaningful change from baseline in patients with nonsegmental vitiligo. TRIAL REGISTRATION The original studies were registered at ClinicalTrials.gov NCT04052425/NCT04057573.

Vitiligo is a skin disease that causes patches of white (depigmented) skin and affects 0.5­2.0% of people worldwide. People with vitiligo often say that restoring color to white patches of skin (repigmentation) is important. Ruxolitinib cream is approved in the USA and Europe for topical treatment of vitiligo in adults and adolescents based on results from the phase 3 TRuE-V1 and TRuE-V2 studies. In these studies, applying ruxolitinib cream twice daily up to 52 weeks resulted in substantial repigmentation, as assessed by the facial and total Vitiligo Area Scoring Index (F-VASI/T-VASI). We aimed to confirm which changes in F-VASI/T-VASI scores represented meaningful improvement for doctors and people with vitiligo. We compared changes in VASI scores with results from two other tools used to assess vitiligo. One tool was based on doctor assessment (Physician's Global Vitiligo Assessment [PhGVA]); the other was based on patient assessment (Patient Global Impression of Change­Vitiligo [PaGIC-V]). The analysis included clinical trial data for 652 people with vitiligo. After 6 months of treatment, median F-VASI and T-VASI scores decreased considerably, indicating improvement in repigmentation. We saw higher VASI scores for disease considered more severe per the PhGVA and PaGIC-V. Changes in VASI scores largely aligned with changes in PhGVA and PaGIC-V scores. We found that F-VASI and T-VASI are reliable tools to assess vitiligo and confirmed that improvement of 0.38­0.60 for F-VASI and 1.69­3.88 for T-VASI scores represent meaningful repigmentation in people with vitiligo on up to 10% of their bodies.