PMS63 HOW ARE FLARES MEASURED TO EVALUATE TREATMENT EFFICACY IN RHEUMATIC CONDITIONS? A REVIEW OF FDA-APPROVED DRUG LABELS

While the term ‘flare’ commonly characterizes periods of increased disease severity, its medical definition varies. Efforts to standardize flare evaluation in therapeutic areas such as rheumatoid arthritis (RA) have been ongoing. This research aimed to explore how flare has been measured in rheumatic conditions in support of product labelling goals for treatment efficacy to identify common practices and discrepancies across flare evaluations. The FDA database was searched for the most recently approved product labels indicated for RA, Juvenile Idiopathic Arthritis (JIA), and ankylosing spondylitis (AS). Labels were reviewed to extract information regarding flare evaluations to inform treatment outcomes. Characteristics of flare evaluations were summarized across the labels. Twenty total unique labels were reviewed. Six flare evaluations (JIA=5, AS=1, RA=0) were described across five product labels approved between 2016 and 2019. Flare evaluations included multiple criteria for assessment. Five flare evaluations utilized the Pediatric American College of Rheumatology (ACR) response criteria 30, which involved a ≥ 30% worsening in ≥ three variables (physician and patient/parent global assessments, number of active joints, range of motion, physical function, and laboratory exam) and prohibited ≥ 30% improvement in ≥1 variable. Three evaluations required at least two active joints in addition to worsening in other variables, while one evaluation also considered fever not due to infection. One evaluation in JIA relied solely on laboratory exams and physician assessments in its flare evaluation. Almost all reviewed evaluations of disease flare used a composite approach based on the ACR30 criteria, while some included additional limitations or variables such as fever.