Relationships between clinical scales and binge eating days in adults with moderate to severe binge eating disorder in two Phase III studies

Objectives In two Phase III studies, lisdexamfetamine dimesylate (LDX) reduced binge eating (BE) days/week in adults with moderate to severe binge eating disorder (BED) and was associated with improvement based on the Clinical Global Impressions-Improvement (CGI-I) scale. In this study, post hoc analyses examined the relationships between clinical observations and clinical rating scales in individuals with BED. Clinical trial registration NCT01718483 (ClinicalTrials.gov/ct2/show/NCT01718483); NCT01718509 (ClinicalTrials.gov/ct2/show/NCT01718509). Methods Two 12-week, double-blind, placebo-controlled studies randomized (1:1) adults meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, BED criteria and with protocol-defined moderate to severe BED (study 1, N=383; study 2, N=390) to placebo or dose-optimized LDX (50 or 70 mg). Assessments included the number of BE days/week, CGI-Severity (CGI-S) and CGI-I scores, and Yale-Brown Obsessive Compulsive Scale modified for Binge Eating (Y-BOCS-BE) total scores. For these post hoc analyses, data were pooled across studies and treatment arms. Statistical assessments included Spearman correlations and equipercentile linking analyses (ELA). Reported P-values are nominal (descriptive and not adjusted for multiplicity). Results At baseline, nominally significant correlations with CGI-S scores were reported for BE days/week (r=0.374; P<0.0001) and Y-BOCS-BE total scores (r=0.319; P<0.0001). Baseline ELA for CGI-S further characterized this relationship: a CGI-S score of 4 (moderately ill) corresponding to 3.504 BE days/week and a Y-BOCS-BE total score of 18.6. Nominally significant correlations with CGI-I scores were reported for changes from baseline at study endpoint for BE days/week (r=0.647; P<0.0001) and Y-BOCS-BE total scores (r=0.741; P<0.0001). ELA for CGI-I scores at study endpoint showed that a CGI-I score of 1 (very much improved) corresponds to a reduction from baseline of 4.504 BE days/week and 19.4 points for Y-BOCS-BE total score. Conclusion These post hoc analyses suggest that indices of global disease severity and improvement positively correlate with BE behavior and with obsessive and compulsive features of BED, measured by the Y-BOCS-BE, supporting the clinical relevance of BED treatment outcomes.