Cinacalcet hydrochloride in combination with alendronate normalizes hypercalcemia and improves bone mineral density in patients with primary hyperparathyroidism

Cinacalcet is effective in controlling the biochemical abnormalities in patients with primary hyperparathyroidism (PHPT) but it seems to be less effective on bone mineral density (BMD). In the same patients, bisphosphonates are reported to be effective on bone resorption but less effective on calcium and PTH excess. In this study, the efficacy of cinacalcet in combination with alendronate has been retrospectively evaluated in patients with PHPT. Twenty-three patients with PHPT who had not been operated were retrospectively investigated. Cinacalcet was evaluated in combination with alendronate in 10 of the 23 patients, and in monotherapy in 13 other patients. Serum calcium, phosphorus and PTH, 24 h urine calcium and phosphorus as well as BMD, evaluated by DXA and expressed as T-score, were measured before and after treatment. In all patients serum calcium and phosphorus and urinary calcium excretion were effectively and stably controlled and PTH was significantly decreased after treatment. There was no difference in the rate of serum calcium and PTH decrease between subjects treated with cinacalcet plus alendronate and those treated with cinacalcet alone. T-score increased by 9.6% at lumbar spine and 3.9% at femur level in the cinacalcet plus alendronate subgroup and was unchanged in the cinacalcet subgroup (P < 0.01). In patients with PHPT, the biochemical abnormalities are rapidly improved by cinacalcet regardless from the administration in monotherapy or in combination with alendronate. BMD is significantly improved in patients receiving cinacalcet plus alendronate and stable in those receiving cinacalcet in monotherapy.