PHILADELPHIA—Cinacalcet plus low-dose vitamin D provides a more effective approach to treating secondary hyperparathyroidism (SHPT) in hemodialysis (HD) patients, according to findings presented at Kidney Week 2011.

In a randomized, open-label trial, Pablo A. Ureña, MD, of Clinique du Landy in Saint-Ouen, France, and colleagues evaluated the efficacy of combined treatment with cinacalcet and low-dose vitamin D in 309 HD patients with parathyroid hormone (PTH) levels above 300 pg/mL. Investigators randomized subjects to receive either cinacalcet plus low-dose vitamin D (20 mcg IV paricalcitol or equivalent per dialysis session if prescribed) or flexible dosing of vitamin D (if prescribed) alone (Flex-D).

The mean dialysis vintage was 7.2 months. Fifty-four percent of subjects were not on vitamin D at study enrollment.

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Study results showed that 63% of the cinacalcet arm achieved a 30% reduction in PTH at six months (the primary endpoint) compared with only 38% of the Flex-D group. Results favored the cinacalcet arm across all PTH strata . The magnitude of the reductions in PTH in the combination group did not differ according to prior vitamin D use at enrollment, according to the researchers. Additionally, a significantly greater proportion of cinacalcet plus low-dose vitamin D patients than the Flex-D group achieved a PTH level of 300 or below at six months (57% vs. 35%).

Patients new to dialysis have a high prevalence of SHPT and initial therapy typically includes vitamin D, calcium supplements, and phosphate binders, Dr. Ureña’s group noted. Treatment with cinacalcet commonly is used later in the course of disease in patients whose SHPT is not adequately controlled with vitamin D.