A recent case series of five postmenopausal individuals with indolent systemic mastocytosis (ISM) and osteoporosis found that treatment with denosumab stabilized or even improved bone health, according to findings published in the Journal of Back and Musculoskeletal Rehabilitation.
While approximately 20% of patients with SM experience osteoporosis or elevated fracture risk, no standard guidelines exist for managing bone disease in SM. Potential options for treating secondary osteoporosis include bisphosphonates — a type of medication often used to slow down bone loss —and denosumab.
Denosumab is a monoclonal antibody therapy that blocks receptor activator of nuclear factor κB ligand (RANKL), a protein that regulates bone remodeling. In SM, activated mast cells produce RANKL, leading to the breakdown of bone tissues.
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The Italian study followed five postmenopausal women with ISM-associated osteoporosis for 36 months. Participants received six doses of denosumab.
At baseline, the researchers recorded five moderate fractures of the vertebrae and one severe fracture. After 18 months, no additional patients experienced vertebral fractures. At 36 months, however, an additional moderate fracture was recorded.
Over the study period, measures of both femoral and lumbar spine bone mass either improved or remained stable. Bone mineral density measures suggested continued osteoporosis, though.
All patients completed the mini-osteoporosis quality of life (mini-OQoL) questionnaire, which records quality of life on a 10- to 70-point scale. From baseline to 36 months, average mini-OQoL scores improved from 54.2 to 67.3.
Limitations of the study include its small sample size and lack of control group. In addition, one individual experienced a fracture during treatment, indicating that denosumab may not eliminate fracture risk in all patients.
In the future, larger prospective studies may help to clarify the role of denosumab in treating SM-associated bone disease.
“Regular monitoring of bone metabolism from the time of diagnosis remains essential in systemic mastocytosisMastocytosis Rare disease caused by the buildup of mast cells. Cutaneous mastocytosis primarily affects the skin and is more common in children, while systemic mastocytosis affects internal organs and is more common in adults. to ensure early intervention and optimal patient management,” the authors concluded.
Read more about bone health in SM: “How to ease bone pain from systemic mastocytosis”
