Can Cinacalcet Replace Parathyroid Intervention in Severe Secondary Hyperparathyroidism?

Abstract

A 6-month observational study was conducted in 61 patients (33 men and 28 women, mean age 54.8 Ϯ 12.4 years) treated with cinacalcet in whom parathyroid intervention was indicated. Thirty-seven patients had baseline intact parathyroid hormone (iPTH) levels of >500 pg/mL, but only five still had levels this high after 6-month cinacalcet therapy. No patients had phosphorus (P), calcium (Ca), or iPTH levels within the target range at baseline, but six patients (9.8%) reached all three target ranges after treatment. The stratum with many patients who had 2-4 enlarged parathyroid glands shifted toward the low PTH groups (iPTH < 300 pg/mL) with treatment. There was less of a tendency for patients with more enlarged glands, that is, 10 mm or larger at baseline, to have a higher PTH level after cinacalcet treatment. There was no significant difference in the total volume of parathyroid glands after treatment, since some glands enlarged while others shrank. These findings indicate cinacalcet to be a potentially useful treatment. Our results suggest that 80% of cases indicated for parathyroid intervention could avoid such interventional therapies with cinacalcet administration. However, the variability in the gland-shrinking effect of cinacalcet on parathyroid glands merits further study.

Histology and immunohistochemistry of the parathyroid glands in renal secondary hyperparathyroidism refractory to vitamin D or cinacalcet therapy

“…Conversely, other authors (31,32) failed to detect significant morphological changes after cinacalcet therapy.…”

“…Nevertheless, this study does not allow to determine whether a regression of PTG with DH is possible after cinacalcet therapy. Actually, this hypothesis has been first based on the data obtained in experimental studies (18,19,20,21,22,23) and then by the US evaluation of PTG (28,29,30,31,32).…”

Review of cinacalcet hydrochloride in the management of secondary hyperparathyroidism

“…In a 6-month observational study in Japan, cinacalcet prevented parathyroidectomy in 80% of patients who had indications for parathyroidectomy. 105 However, the indications for parathyroid intervention in this study of 61 patients were much more aggressive than guidelines practiced elsewhere. 105 Cinacalcet, by reducing PTH to 250 pg/mL in 48% of patients with PTH range of 500 to 800 pg/mL and in 20% of patients with 4800 pg/mL, eliminated indications for parathyroidectomy in Japanese patients.…”

“…105 However, the indications for parathyroid intervention in this study of 61 patients were much more aggressive than guidelines practiced elsewhere. 105 Cinacalcet, by reducing PTH to 250 pg/mL in 48% of patients with PTH range of 500 to 800 pg/mL and in 20% of patients with 4800 pg/mL, eliminated indications for parathyroidectomy in Japanese patients. 106 Therefore, the marked PTH-lowering effects of cinacalcet are sometimes referred to as ''medical parathyroidectomy.''…”

A Japanese approach for CKD-MBD

“…24 Several studies have shown the efficacy of cinacalcet for dialysis patients with secondary hyperparathyroidism refractory to treatment with active vitamin D derivatives and those with marked parathyroid hyperplasia, in whom surgical PTx may be the treatment of choice. 32, 33 Indeed, a post-hoc analysis of randomized clinical trials reported significant reductions in PTx in patients treated with cinacalcet compared with the placebo plus standard of care group. 34 Thus, indications for PTx and cinacalcet treatment overlap significantly.…”