Endocrine Abstracts

Primary hyperparathyroidism (PHPT) is often associated with reduced bone mineral density (BMD). An open-labeled, prospective trial was conducted to determine whether denosumab 60 mg subcutaneously given every 6 months, maintains or improves BMD in patients with PHPT.

Six patients had symptomatic PHPT and met surgical guidelines however refused surgery, and twelve patients had mild PHPT, asymptomatic except low BMD. The primary outcome index, BMD, was measured at the lumbar spine (LS) and femoral neck (FN) after six and 12 months by dual-energy X-ray absorptiometry. Serum calcium, phosphorous and PTH, and urinary calcium excretion were monitored every 3 months.

Treatment with denosumab was associated with a significant (5.8±0.4%; P<0.01) increase in LS BMD after 12 months in comparison with baseline. FN BMD increased significantly at 12 months with denosumab by 2.3%±0.7 (P<0.01) from baseline. Serum calcium, phosphorus and PTH, and urine calcium excretion did not change significantly with denosumab therapy. In PHPT, denosumab given subcutaneously twice yearly, significantly increases BMD at the LS and FN at 12 months from baseline values with stable serum calcium and PTH levels. Denosumab may be a useful alternative to parathyroidectomy in PHPT among those with low BMD, who are candidates for surgery but either decline or for whom surgery is contraindicated.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.