Clinical trial of zoledronic acid in children and adolescents with Duchenne muscular dystrophy

INTERVENTION: to assess whether zoledronic acid 0.025mg/kg/dose as an intravenous preparation infused over 30 minutes, at 0,3 months then 0.05mg/kg/dose at 6,12 and 18 months is superior to calcium as an oral tablet plus vitamin D as orally administered capsule, to improve bone density and reduce fracture risk in boys with Duchenne muscular dystrophy CONDITION: Duchenne muscular dystrophy osteopaenia PRIMARY OUTCOME: Change in lumbar spine (LS) areal bone mineral density (aBMD) Z‐score as assessed by dual Xray absorptiometry (DEXA), with volumetric calculation for each subject to account for size variability [Bone mineral apparent density (BMAD)]. SECONDARY OUTCOME: Between‐treatment differences for the change from baseline in Lumbar Spine(LS) areal BMD Z‐score, LS and total body Bone Mineral Content(BMC) assessed by DEXA and in bone turnover markers assessed by alkaline phosphatase,urine deoxypyridinoline cross links Between‐treatment differences for the change from baseline in tibial metaphyseal BMC and volumetric BMD(vBMD), and diaphyseal BMC, vBMD and cross‐sectional area on peruipheral Quantitative Computed Tomography(pQCT) Between‐treatment differences for the number of patients with new clinical fractures relative to baseline as assessed by history of overt long bone fracture and by vertebral Xrays Between‐treatment differences for the proportion of patients with new vertebral fractures and vertebral morphometry relative to baseline using vertebral Xrays to be assessed by clinician blinded to the type of intervention change from baseline in pain scores using the WONG BAKER pain faces scale where the children rate their pain from 0 to 10 using pictures of emotional faces as a guide Change from baseline in walking ability assessed by the six minute walk test which measures how far a child can walk in six minutes. INCLUSION CRITERIA: All boys between 6‐16 years with confirmed Duchenne Muscular Dystrophy (DMD) and who are receiving glucocorticoid therapy (this is universally prednisolone)