A year-long prospective study published in Pediatric Neurology found that intravenous zoledronic acid treatments improved bone density in boys living with Duchenne muscular dystrophy (DMD) without causing major side effects.
Bone health remains a major concern in DMD. Long-term corticosteroid use, decreased mobility and delayed puberty increase the risk of osteoporosis and fractures, including compression fractures in the spine that often go unnoticed but can cause pain, scoliosis and breathing issues. Bisphosphonate treatments, like zoledronic acid, can help prevent bone loss and lower the risk of fractures.
To better understand how zoledronic acid affects patients with DMD, the study’s authors enrolled 55 boys aged five to 18 with a history of fractures or evidence of significant bone loss. Participants in the study received three doses of zoledronic acid over 12 months and underwent clinical assessments with bone imaging before and after treatment.
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Bone mineral density on imaging scans is described as a “Z-score,” where a score of zero indicates normal bone density, and a negative score, such as –2.00, indicates significant bone loss.
After one year, average bone mineral density scores improved at two key sites. Lumbar spine Z-scores increased by 0.67 points, while femur neck Z-scores improved by 0.49 points. Gains were seen in both walking and nonwalking boys, although improvements at the hip were more pronounced in those who were still walking.
“Intravenous zoledronic acid significantly improved bone mineral density and reduced bone turnover in boys with Duchenne muscular dystrophy without major adverse effects,” the study’s authors wrote.
Despite these improvements, fractures remained common.
At the start of the study, 60% of boys had at least one vertebral compression fracture. At follow-up, about one-quarter of participants developed new vertebral fractures. All newly identified fractures were mild and did not cause symptoms, highlighting the need for continued monitoring even as bone density improves.
The study also found a significant decrease in a blood marker linked to bone breakdown, indicating that zoledronic acid slowed bone loss. However, measures of physical function and quality of life mostly stayed the same during the study.
Zoledronic acid was generally well tolerated. Fever and flu-like symptoms were the most common side effects, especially after the first infusion, and no serious long-term safety concerns were reported.
The authors identified several limitations of the study, such as the absence of a control group and a relatively short follow-up period. They highlighted that longer, controlled studies are necessary to determine whether earlier or extended treatment might better prevent fractures in this population.
Overall, the findings support zoledronic acid as an effective option for increasing bone density in boys with DMD, while highlighting that fracture risk remains an ongoing concern requiring regular imaging and follow-up.
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