Anabolic treatment with RHPTH of duchenne muscular dystrophy related osteoporosis: a case report

Patients with Duchenne muscular dystrophy (DMD) experience secondary osteoporosis with high fracture rate due to immobilization and glucocorticoid (GC) use. Vertebral fractures are a common finding in these young subjects, and may lead to severe pain and worsening of respiratory function due to chest deformity when multiple fractures coexist. Teriparatide (rhPTH) was previously proven to enhance bone formation and bone mineral density (BMD) and to reduce vertebral fracture rate in postmenopausal and glucocorticoid induced osteoporosis, but no data are available in DMD. We describe the case of a 20 years old GC treated DMD subject suffering from multiple symptomatic, severe vertebral fractures, treated with rhPTH. BMD was measured by DXA at lumbar spine (L1-L4) and vertebral fractures were defined by morphometric examination, in accordance to Genant’s classification, at baseline and after 12 months. Bone resorption (CTX) and bone formation (BGP) markers were assessed in addition to other laboratory and clinical data every 3 months for 12 months. At the same time, VAS was used to evaluate severity of back pain. Three severe vertebral fractures were recognized at baseline (D8, D11, D12), and a Z-score measurement of -6.7 SD was recorded. Calcifediol supplementation, previously given to maintain adequate 25(OH)D levels, was administered in addition to rhPTH. After 12 months, Z-score value increased significantly (+10%) and no further clinical and/or morphometric vertebral fractures were detected. We observed an early increase (after 3 months, p<0.05) of bone turn-over markers, especially for BGP, which was maintained after 12 months, highlighting the anabolic window on bone metabolism of such treatment. Moreover, rhPTH significantly reduced back pain intensity already after 3 months, with disappearance of pain after 6 months. These preliminary data suggest rhPTH may be a safe and efficacy new possible treatment of severe osteoporosis in DMD patients.