Comparison of Daily Deflazacort vs Prednisone Treatment on Disease Milestones and Muscle Fat Accumulation in DMD

Topic:

Translational Research

Poster Number: P153

Author(s):

Rebecca J Willcocks, PhD, University of Florida, Timothy J Bowen, University of Florida, Ishu Arpan, PhD, n/a, Sean C Forbes, PhD, University of Florida, William D Rooney, PhD, Oregon Health and Science University, John F Brandsema, MD, Children’s Hospital of Philadelphia, Michael J Daniels, ScD, University of Florida, Glenn A Walter, PhD, University of Florida, Krista Vandenborne, PhD, University of Florida

Corticosteroids slow disease progression in Duchenne muscular dystrophy (DMD), however there is considerable variability in the type, dose, and regime used. This study aimed to characterize corticosteroid use of participants in the ImagingNMD study and investigate relationships between disease progression rate and corticosteroid type and dose. ImagingNMD is an ongoing multisite longitudinal observational study initiated in 2010 with annual measurements. Participants or their parents self-reported medication use, including corticosteroid use, at each visit. Single-voxel MRS was performed in the soleus (SOL) and vastus lateralis (VL) muscles and relaxation-corrected as previously described. Longitudinal changes in fat fraction with increasing age were captured as the midpoint of a fitted sigmoid curve (mu), indicating the age at ~50% disease progression for that muscle. Age at loss of ambulation was captured to the nearest month based on participant or parent report. This study consisted of 125 males with DMD (9.2 ± 2.6 years old at enrollment). 45 study participants had varied corticosteroid regimes during participation, with changes in steroid type or regime, or substantial changes in dose. 66 participants consistently took daily deflazacort during study participation (0.65 ± 0.19 mg/kg/day), while 14 participants consistently took daily prednisone (0.48 ± 0.14 mg/kg/day). In this subgroup, significantly higher mu values, indicative of slower disease progression, were observed in deflazacort-treated participants compared to prednisone-treated participants (Deflazacort: VL: 13.4 ± 5.6 years, SOL: 17.5 ± 5.8 years; Prednisone: VL: 11.6 ± 0.2 years, SOL: 14.9 ± 0.9 years; p < 0.05). Age at loss of ambulation was significantly higher in participants on deflazacort (Deflazacort: median 15.7 ± 3.8 years; Prednisone: median 12.7 ± 0.8 years; p < 0.05). Muscle disease progression was slower in deflazacort-treated subjects compared with prednisone-treated subjects, supporting previous reports of delayed loss of ambulation with prednisone compared with deflazacort in DMD.