Effect of deflazacort and prednisone on muscle enzymes in the treatment of duchenne muscular dystrophy

Objective: To describe the effects of deflazacort and prednisone on muscle enzymes over 1 year during the treatment of boys with Duchenne muscular dystrophy (DMD). Background: DMD is an X-linked disease that affects approximately 1 in 5,000 live male births. Corticosteroids (deflazacort and prednisone) are shown to prolong independent ambulation, improve pulmonary function, delay the onset of cardiomyopathy and reduce the incidence of scoliosis. Methods: This randomized, double-blind, placebo-controlled, active comparator, Phase 3 study evaluated the efficacy of two deflazacort doses (0.9 and 1.2 mg/kg/day) compared to prednisone (0.75 mg/kg/day) and placebo for treatment of boys with DMD. The first segment compared deflazacort and prednisone to placebo over 12 weeks. The second segment compared the two doses of deflazacort to prednisone from 12 to 52 weeks of treatment. Creatine kinase (CK), lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) were measured at baseline and 6, 24, and 52 weeks on treatment (in U/L). Results: A total of 196 participants from 9 centers were randomized to the 4 treatment groups. Baseline CK, LDH and AST were comparable between the groups. At Week 6, AST, CK and LDH significantly decreased with 0.9 and 1.2 mg/kg/day of deflazacort and prednisone treatment compared to placebo (AST: -30, -51, -49, +14 respectively; CK: -3529, -2895, -3748, +840 respectively; LDH: -226, -207, -196, +92 respectively; p<0.05). From Baseline to Week 52, deflazacort 0.9 mg/kg/day had greater but not statistically significant decreases in AST, CK, and LDH than deflazacort 1.2 mg/kg/day and prednisone (AST: -15.8, +13.1, -10 respectively; CK: -3638,-1015, -2737 respectively; LDH: -270, -162, -157 respectively). Conclusions: Deflazacort and prednisone improve biomarkers of muscle breakdown compared to placebo in patients with DMD. Continued improvement over 1 year was realized in the treatment groups with increased numeric improvements demonstrated with deflazacort 0.9 mg/kg/day compared to prednisone.