June 2020
Volume 61, Issue 7
Free
ARVO Annual Meeting Abstract  |   June 2020
Psychometric evaluation of a modified version of the Visual Function Questionnaire using data from a Phase III trial in biallelic RPE65 mutation-associated inherited retinal dystrophy
Author Affiliations & Notes
  • Judit Banhazi
    Novartis Pharma AG, Basel, Switzerland
  • Daniel Viriato
    Novartis Pharma AG, Basel, Switzerland
  • Claudio Spera
    Novartis Pharma AG, Basel, Switzerland
  • Nicola Williamson
    Adelphi Values, United Kingdom
  • Helena Bradley
    Adelphi Values, United Kingdom
  • Elizabeth Exall
    Adelphi Values, United Kingdom
  • Jean Bennett
    Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
    Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
  • Footnotes
    Commercial Relationships   Judit Banhazi, Novartis Pharma AG (E); Daniel Viriato, Novartis Pharma AG (E); Claudio Spera, Novartis Pharma AG (E); Nicola Williamson, Adelphi Values (E); Helena Bradley, Adelphi Values (E); Elizabeth Exall, Adelphi Values (E); Jean Bennett, Foundation Fighting Blindness (F), NIH (F), Spark Therapeutics Inc. (F)
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2020, Vol.61, 1578. doi:
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      Judit Banhazi, Daniel Viriato, Claudio Spera, Nicola Williamson, Helena Bradley, Elizabeth Exall, Jean Bennett; Psychometric evaluation of a modified version of the Visual Function Questionnaire using data from a Phase III trial in biallelic RPE65 mutation-associated inherited retinal dystrophy. Invest. Ophthalmol. Vis. Sci. 2020;61(7):1578.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Voretigene neparvovec (VN) is the first ocular gene therapy approved for patients with biallelic RPE65 mutation-associated inherited retinal dystrophy (IRD). A modified version of the Visual Function Questionnaire (mVFQ-25) was developed to address the unmet need for a patient-reported outcome for this population. This retrospective analysis of Phase III clinical trial data evaluated the psychometric properties of the mVFQ-25 as an assessment of functional vision or activities of daily living (ADLs) in IRDs due to RPE65 mutations.

Methods : Thirty-one patients and/or their caregivers completed the mVFQ-25 at baseline (BL), days 30, 90, 180 and 1-year reporting perceived difficulty of ADLs. Patients also completed the Multi-luminance Mobility Test (MLMT), a novel endpoint assessing functional vision at various light levels experienced in ADLs. Psychometric analyses assessed item (question) response distributions, question correlations, reliability (internal consistency and test-retest reliability), construct validity (convergent and discriminative validity), responsiveness and interpretation of scores.

Results : Findings indicated sensitivity to improvements in functional vision following VN treatment, despite skewed item response distributions across timepoints. Correlations among items were weak-to-moderate (0.00–0.66) at BL and slightly stronger at 1-year (0.00–0.87). Internal consistency was excellent across timepoints (Cronbach’s alpha=0.854–0.950) and test-retest reliability was strong between days 90–180 (Intraclass Correlation Coefficient=0.912), indicating excellent reliability. Moderate correlations with similar measures post-BL (r=−0.48 to 0.76) supported convergent validity. Statistically significant differences post-BL (p<0.001) in mean mVFQ-25 scores between groups defined by MLMT scores, supported discriminative validity. Statistically significant changes in mVFQ-25 for patients who had improved MLMT scores supported responsiveness. Distribution and anchor-based analyses to define meaningful change thresholds suggested that a 1.5-point change or more can be considered meaningful.

Conclusions : Results support the reliability, validity and responsiveness of mVFQ-25 as a measure of functional vision for use in patients with IRD due to RPE65 mutations.

This is a 2020 ARVO Annual Meeting abstract.

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