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Teriparatide increased BMD, bone strength in mild osteogenesis imperfecta
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Teriparatide therapy significantly increased hip and spine bone mineral density and estimated bone strength in adults with mild osteogenesis imperfecta, recent data suggest.
“These results indicated that despite an underlying genetic defect in [osteogenesis imperfecta] that impairs bone matrix synthesis and results in osteoblastic dysfunction and remodeling abnormalities, anabolic therapy is capable of increasing bone formation and bone mass,” researchers wrote.
Patients with osteogenesis imperfecta (n=79) were randomly assigned to teriparatide 20 mcg (Forteo, Eli Lilly and Company) or placebo for 18 months.
Those who were assigned to teriparatide displayed an increased percentage change in areal BMD of the lumbar spine (6.1%) compared with patients assigned to placebo (2.8%; P<.05), according to data.
There was a 3% change to the vertebral BMD (18%) and bone strength (15%) in those assigned to teriparatide. Conversely, vertebral BMD (–5%) and bone strength (–2%) decreased in those assigned to placebo (P<.05), researchers wrote.
Teriparatide therapy was associated with a 10% increase in serum procollagen type 1 N-terminal propeptide (135%) and urine collagen N-telopeptide (64%) levels, according to data. These elevated levels were not as significant in other forms of osteogenesis imperfecta, whereas the most significant findings were observed among patients with mild forms of the disease.
Eleven patients (29%) assigned to teriparatide reported fractures during the study (OR=0.73; 95% CI, 0.28-1.9) compared with those assigned to placebo (36%). However, changes to areal BMD were not associated with the likelihood of fractures, according to data.
“These data should prompt larger trials to evaluate whether anabolic treatment results in a reduction in the burden of fractures in those patients. On the other hand, our results suggest that anabolic therapies may be less effective in patients with more severe forms of [osteogenesis imperfecta], and future studies should specifically assess the usefulness of therapies in light of disease severity,” researchers wrote.
Disclosure: Orwoll consults with Eli Lilly and Company. Two researchers report financial ties with ON Diagnostics. All other researchers report no relevant financial disclosures.
Perspective
Back to TopJoel S. Finkelstein , MD
The paper by Orwoll and colleagues reports the results of a well-designed and well-executed randomized controlled clinical trial assessing the effects of teriparatide, the only anabolic agent currently approved by the FDA, on BMD, bone turnover markers, and estimated bone strength in patients with various forms of osteogenesis imperfecta.
There was a significant improvement in BMD and predicted bone strength, as has been observed in other osteoporotic populations treated with teriparatide. In that respect, the response of these patients to teriparatide is not surprising. In fact, what has been surprising over the years is that the response to therapy does not seem to be related to the underlying etiology of the patients’ osteoporosis. Patients with low bone formation respond both to anti-resorptive and anabolic agents as do patients with high bone resorption. If you just looked at the graphs of the data from Orwoll’s current study without knowing who the experimental patients were, you could easily suspect that these subjects were women with postmenopausal osteoporosis.
Nonetheless, the important clinical message from this study is that teriparatide is a beneficial agent for treating patients with type I osteogenesis imperfecta and it provides another useful option in managing this challenging disorder.
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