Besides its many uses in the treatment of inflammations and autoimmune diseases2, the benefits of deflazacort on DMD emerged from several studies^{1,5,6,7,8,12,15}. Corticosteroids are the standard therapy to delay DMD progression12 with some reports indicating less weight gain in patients using deflazacort than those using other corticosteroids, like prednisolone^{1,5,7,8,12,13,15}.

In February 2017 deflazacort received FDA approval for the treatment of DMD under the name Emflaza, manufactured by Marathon Pharmaceuticals^4,14. This approval was based on a study of 196 boys, ranging from 5 to 15 years old¹⁵. The study lasted 52 weeks and compared deflazacort at two different dosages (0.9 or 1.2 mg/ kg/ day) with prednisone (another corticosteroid commonly used to treat DMD) and placebo.

After 12 weeks of treatment, both deflazacort (at both dosages) and prednisone showed superior changes in average muscles strength scores: deflazacort produced a score of 0.15 with the dosage of 0.9 mg/ kg/ d (95% CI 0.01, 0.28)16 and a score of 0.26 with the of dosage 1.2 mg/ kg/ d (95% CI 0.12, 0.40); prednisone produced a score of 0.27 (95% CI 0.13—0.41); placebo produced a score of -0.1 (95 % CI -0.23, 0.03)¹⁵.

Moreover, both medications were better than placebo on several timed motor function tests (i.e., time to stand from supine, time to climb four stairs and time to walk or run 30 feet)¹⁵. From week 12 to week 52 the group treated with deflazacort with the dosage of 0.9 mg/ kg/ d showed better results in changes of average muscle strength score (0.17, 95% CI 0.03, 0.31) than the group treated with prednisone (-0.12, 95% CI -0.26, 0.03)¹⁵.