What is the role of pharmacologic therapy in the treatment of polyostotic fibrous dysplasia (PFD) in McCune-Albright syndrome (MAS)?

Updated: Jan 05, 2021
  • Author: Gabriel I Uwaifo, MD; Chief Editor: George T Griffing, MD  more...
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The bony disease associated with MAS (PFD) is very difficult to treat. Currently, no clinically proven medical therapies are available. Studies of oral and intravenous (IV) bisphosphonates (particularly pamidronate, alendronate, and zoledronate) suggest that these agents may have beneficial effects on the bony disease, with regard to reducing both bone pain and the frequency of pathologic fractures, as well as to slowing the evolution of the bony disease. [54, 8] However, data on the ability of bisphosphonates to heal fibrous dysplasia are conflicting.

One study found that long-term bisphosphonate treatment had beneficial effects on bone health in MAS; fracture rate and bone pain were reduced, and radiologic evidence of long-bone pathology resolution was observed. [55] Another suggested that bisphosphonate may be helpful. [56] A 2011 case report found continuous low-dose oral alendronate to be helpful in a 79-year-old woman with PFD. [57]

However, another study found that bisphosphonate treatment of PFD in children with MAS did not arrest progressive bone pathology. [58]  Similarly, a study by Florenzano et al reported that bisphosphonates did not affect disease burden progression in pediatric patients with FD. Moreover, although the investigators found that in adults with FD there was a decrease in bone-turnover markers and other disease-activity markers, these changes were determined to be age related and not significantly associated with bisphosphonate treatment. [59]

Nonetheless, a literature review by Chapurlat and Legrande indicated that, based on observational studies, IV therapy with pamidronate can significantly reduce bone pain and bone resorption in patients with FD/MAS. However, reports regarding the oral bisphosphonates alendronate and risedronate did not find these to effectively decrease bone pain, although several studies did indicate that, like pamidronate, the oral bisphosphonates can increase bone mineral density at FD sites. [60]

Tocilizumab, an interleukin-6 blocker used for rheumatoid arthritis, has been employed as a treatment for a polyostotic variant of bone fibrous dysplasia. [61]

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