Bisphosphonates not always effective for treatment of osteogenesis imperfecta
NASHVILLE, Tenn. — Treatment with bisphosphonates does not always lead to a decrease in fracture rates among children and adults with osteogenesis imperfecta, according to recent study findings.
“The question is, is there a definable difference in terms of looking at bone biomarkers or fracture rates in terms of patients who do respond to bisphosphonate treatment or don’t,” Jay Shapiro, MD, of Kennedy Krieger Institute in Baltimore, told Endocrine Today.
Shapiro and colleagues evaluated 19 children who were treated with pamidronate to determine metabolic and bone biomarker responses to the treatment in patients who either do or do not have a decrease in fractures after the treatment. The children were divided into responders and nonresponders.
In the child participants, responders had a shorter duration of treatment (42.6 months) compared with nonresponders (72.7 months; P = .02).
“The reason for the difference in duration of treatment is that in people who don’t respond, there is pressure to keep treating because maybe it might get better,” Shapiro said.
There were fewer fractures among child responders (n = 4.8) during the treatment period compared with nonresponders (n = 15.6; P = .02). No differences were found between responders and nonresponders for vitamin D levels, phosphorus, alkaline phosphatase, osteocalcin and C-telopeptide.
All responders among the children were type 1 osteogenesis imperfecta, whereas nonresponders were type 1, 3 and 4.
The researchers also evaluated 34 adults and 12 nontreatment controls to determine fracture incidence during 5-year intervals before treatment and a minimum of 3 years after treatment.
“When you look at adults, in general, it’s known that adults don’t generally respond to bisphosphonates,” Shapiro said.
No difference was found in the number of fractures among adults during the 5-year period before treatment or after treatment. Similarly, no significant differences were found among adults during the 5-year intervals for vitamin D, calcium, alkaline phosphatase, phosphorus, C-telopeptide or N-telopeptide. The nontreated controls exhibited higher levels of osteocalcin compared with the treated group (P < .001).
Treated adults were type 1, 3 and 4 and controls were type 1 and 4.
“What doctors don’t understand is that osteogenesis imperfecta is not standard osteoporosis,” Shapiro said. “These kinds of drugs for standard osteoporosis are great, but it does not apply to adults with osteogenesis imperfecta or does not apply to many children with osteogenesis imperfecta who will continue to fracture even though they’re treated and even though they get treated for many, many more months than they should be.” – by Amber Cox
Shapiro J, et al. Abstract #1235. Presented at: Presented at: AACE 24th Annual Scientific & Clinical Congress; May 13-17, 2015; Nashville, Tenn.
Disclosure: Endocrine Today was unable to confirm any relevant financial disclosures.