Glucocorticoid (GC) steroids are a mainstay of therapy for Duchenne Muscular Dystrophy, where they have been shown to prolong ambulation in for DMD in random clinical trials (Gloss et al., 2016). Dosing regimen vary for DMD, but most trials utilized oral daily dosing at 0.75- 1 mg/kg of prednisone or deflazacort (Birnkrant et al., 2018). The age at which to begin oral glucocorticoids and the age at which to cease steroid use are not well established by clinical trial investigation. High dose weekend dosing of oral glucocorticoid steroids has also been suggested to be noninferior to daily dosing when evaluated in a year-long study in DMD, and this approach is preferred in some settings since related to a reduced side effect profile, particularly with respect to behavioral changes which can occur with daily GC steroid dosing in children (Escolar et al., 2011). The use of GC steroids for other forms of muscular dystrophy, including Becker Muscular Dystrophy (BMD) and the Limb Girdle Muscular Dystrophies (LGMDs) is not considered standard of care and has insufficiently been investigated by randomized clinical trials (RCT). An RCT of GC steroids in LGMD 2B (DYSF mutations) was associated with unfavorable outcomes in the steroid treated group (Walter et al., 2013).

Recently, weekly steroid dosing was investigated in preclinical mouse models of muscular dystrophy, including the mdx mouse model of DMD/BMD and two models of LGMD, including LGMD 2B (DYSF) and 2C (SGCG) (Quattrocelli et al., 2017a; Quattrocelli et al., 2017b). All three models showed improved strength and reduced fibrosis with weekly GC steroid dosing. Moreover, in unpublished data, long term studies (24-52 weeks duration) in mice, showed favorable results with improved muscle strength in the mdx and DYSF models.

The investigators propose to carry out an open label safety and efficacy trial of oral weekly GC steroids in patients with BMD and LGMD subtypes. Subjects will be recruited based on age, molecular diagnosis of BMD and LGMD subtypes, and willingness to participate. Both ambulatory and nonambulatory subjects will be included. Subjects will be excluded if they have diabetes mellitus, full time ventilator use, or severely compromised cardiac function, including symptoms referable to heart failure. Subjects must provide consent.

Subjects will be asked to take weekly GC oral prednisone dosed based on weight (1mg/kg for patients who weigh less than or equal to 70 kg and 0.75 mg/kg for patients who weigh more than 70 kg). Subjects will also be instructed to take their weekly prednisone on Mondays after their last meal between 7 and 9 PM. Prior to initiation, subjects will provide a blood sample for baseline screening including serum chemistries, HgbA1-C, creatine kinase, and lipid panel (HDL, LDL, triglycerides, and total cholesterol) and for exploratory biomarkers. Subjects will also provide a urine sample to analyze changes in metabolic biomarkers that are excreted. Subjects will have a physical exam and medical record review. Subjects will have strength testing and complete 10 meter timed run test in addition to a 6 min walk test (if ambulatory). Subjects will be asked to complete quality of life questionnaire. At 6 months, subjects will be evaluated with a physical exam, strength testing, spirometry, 10 meter timed run test and 6 min walk test (if ambulatory), blood draw for serum chemistry, HgbA1-C, creatine kinase, lipid panel and for exploratory biomarkers. Subjects will also provide a urine specimen to be analyzed for any changes in excretion of metabolic markers as an exploratory endpoint. Subjects will be asked to complete a quality of life questionnaire. An MRI/ MRS will be performed before starting GC oral prednisone and at 6 months.