Bone health was found to be stable in adolescent and young adult patients receiving teriparatide for severe osteoporosis in Duchenne muscle dystrophy (DMD), according to study results published in Osteoporosis International.
Teriparatide has been used to treat osteoporosis in adults, but its use in pediatric patients has not been fully understood. Investigators aimed to characterize the safety and efficacy of teriparatide treatment for severe osteoporosis in patients with DMD. Inclusion criteria were long-term glucocorticoid therapy and severe osteoporosis despite treatment with bisphosphonates or intolerance to bisphosphonates.
A total of 6 patients (median age at baseline, 17.9 years [age range, 13.9-22.1 years]) were included in the study. After discontinuation of bisphosphonate therapy, teriparatide (20 µg) was administered daily by subcutaneous injection. Fracture outcomes, vertebral morphometry, bone mineral density (BMD), and bone formation markers were assessed every 6 months for 2 years. Researchers also performed laboratory testing at 1 and 3 months for safety monitoring.
All patients had a history of long bone and vertebral fractures before initiating teriparatide treatment. Over the course of 20.3 patient-years before treatment initiation, a combined 17 long bone fractures were reported at a rate of 0.84 fractures per year. During the course of teriparatide treatment, 1 fracture occurred, at a decreased fracture rate of 0.09 fractures per year.
No significant changes in lumbar vertebral heights were observed over 2 years of teriparatide treatment. Previous vertebral fractures remained stable or improved during treatment. Absolute areal BMD and bone mineral content at all skeletal sites remained stable during treatment, although BMD Z-scores declined over time. Serum bone-specific alkaline phosphatase also remained stable over the course of treatment, with modest increases in procollagen type 1 amino-terminal propeptide (P1NP) concentration observed at 2 years. Laboratory safety indices remained stable and within normal limits over 2 years of treatment for all patients. No adverse events related to treatment were reported; a patient died 1 year after initiation of treatment because of cardiac arrest attributed to congestive heart failure unrelated to teriparatide treatment.
Researchers acknowledged that the use of BMD as a measure of bone health in patients with DMD was limited, but noted that trajectories for absolute BMD values may still serve as a useful metric for treatment response.
“In  patients with DMD treated with teriparatide for severe osteoporosis, we observed stable bone health and modest increases in P1NP, without safety concerns,” the researchers concluded. “Further studies are needed to better understand teriparatide efficacy for treatment of osteoporosis in patients with DMD.”
Nasomyont N, Keefe C, Tian C, et al. Safety and efficacy of teriparatide treatment for severe osteoporosis in patients with Duchenne muscular dystrophy. Osteoporos Int. Published online July 17, 2020. doi:10.1007/s00198-020-05549-z