Comparison of the Quantitative Myasthenia Gravis (QMG) and Myasthenia Gravis Activities of Daily Living (MG-ADL) scores in the MGTX Randomized Trial (P2.2-102)

Objective: To qualitatively and quantitatively compare the performance of QMG and MG-ADL measures during the MGTX trial. Background: QMG and MG-ADL are the two most common measures of Myasthenia Gravis (MG) disease severity, but no gold standard has yet been established. The MGTX trial collected longitudinal MG-ADL and QMG measures on patients randomized to thymectomy plus prednisone (TPP) or prednisone alone (PA). Design/Methods: MG-ADL and QMG disease measures were analyzed by treatment group and follow-up time for the 118 patients with at least one follow-up visit using generalized linear models with repeated measures (GLMs) and autocorrelation [AR(1)] covariance. Models were compared to determine if both measures similarly captured the group difference and time trend in disease status. Model distributional assumptions were also evaluated. Correlations between the measures were examined for the 123 patients having any observations. Multivariate relationships between QMG and MG-ADL means, standard deviations, and observed correlations were examined graphically and using multivariate ANOVA. Results: Assuming normality for QMG appears adequate, but MG-ADL is better fit by a Poisson distribution. Treatment group and time were significant (p The baseline correlation between the measures was 0.65 (TPP) and 0.53 (PA). The increasing multivariate relationship describing the observed correlation between the two measures and their means (HLT p Conclusions: QMG and MG-ADL are clearly correlated and appear to perform similarly in measuring MG severity. The model curves and AR(1) coefficients are similar reflecting treatment modifications across study visits. Normality assumptions apply in modeling QMG, thereby facilitating statistical analyses and enabling a wider range of model assessments. Disclosure: Dr. McPherson has received research support from Ra Pharmaceuticals, Alexion Pharmaceuticals, Myasthenia Gravis Foundation of America. Dr. Aban has nothing to disclose. Dr. Duda has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Ra Pharmaceuticals. Dr. Duda holds stock and/or stock options in Ra Pharmaceuticals. Dr. Farzaneh-Far has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Ra Pharmaceuticals. Dr. Farzaneh-Far holds stock and/or stock options in Ra Pharmaceuticals. Dr. Wolfe has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Grifols, Shire, and Alexion. Dr. Wolfe has received research support from ArgenX, Ra, and Immunovant. Dr. Kaminski has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Ra Pharmaceuticals and GT Biopharma. Dr. Cutter has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with AMO Pharmaceuticals, Biolinerx, Horizon Pharmaceuticals, Hisun Pharmaceuticals, Merck, Merck/Pfizer, Opko Biologics, Neurim, Novartis, Ophazyme, Sanofi-Aventis, Reata Pharmaceuticals, Receptos/Celgene, Teva pharmaceuticals, NHLBI, NICHD, Atara Biotherapeutics, Axon, Biogen, Argenix, Brainstorm Cell Therapeutics, Charleston Labs Inc, Click Therapeutics, Genzyme, Genentech, GW Pharma, Klein-Buendel Incorporated, Medimmune, Medday, Novartis, Roche, Scifluor, Somahlution, Teva pharmaceuticals, TG Therapeutics, UT Houston. Dr. Cutter has received personal compensation in an editorial capacity for Statistical editor for the Journal of the American Society of Nephrology. Dr. Cutter has received research support from Via MGFA.