No significant changes were observed in four of them, a decrease was recorded in two patients, and only one patient with generalized osteitis fibrosa cystica showed an increase in PTH from 1871 to 5000 pg/mL on the 10th day after denosumab administration (Table 1), and stabilization of blood calcium level at 3 mmol/L. Here, PTH is linked to osteitis fibrosa.