CJASN ePress. Published on June 26, 2014 as doi: 10.2215/CJN.10661013 Article A Randomized Multicenter Trial of Paricalcitol versus Calcitriol for Secondary Hyperparathyroidism in Stages 3–4 CKD Daniel W. Coyne,* Seth Goldberg,* Mark Faber,† Cybele Ghossein,‡ and Stuart M. Sprague§ Abstract Background and objectives Calcitriol is used to treat secondary hyperparathyroidism in patients with CKD. *Renal Division, School of Medicine, Paricalcitol is less calcemic and phosphatemic in preclinical studies and in some trials in dialysis patients, but Washington head-to-head comparisons in nondialysis patients are lacking. A large meta-analysis of trials concluded that these University, St. Louis, agents did not consistently reduce parathyroid hormone (PTH) and increased the risk of hypercalcemia and Missouri; †Division of hyperphosphatemia. Therefore, the objective of this multicenter trial was to compare the rate of hypercalcemia Nephrology and – Hypertension, Henry between calcitriol and paricalcitol, while suppressing PTH 40% 60%. Ford Hospital, Detroit, Michigan; ‡Divison of Design, setting, participants, & measurements Patients with stages 3–4CKD(n=110) with a PTH level .120 pg/ml Nephrology, Feinberg were recruited and randomized to 0.25 mg/d of calcitriol or 1 mg/d of paricalcitol between April 2009 and School of Medicine, July 2011. Subsequent dose adjustments were by protocol to achieve 40%–60% PTH suppression below Northwestern fi . University, Chicago, baseline. The primary endpoint was the rate of con rmed hypercalcemia of 10.5 mg/dl between groups. Illinois; and §Division of nephrology and Results Forty-five patients in each group completed the 24 weeks of treatment. Both agents suppressed PTH Hypertension, effectively (252% with paricalcitol and 246% with calcitriol; P=0.17), although the paricalcitol group reached a Northshore University Health System, 40% reduction in PTH sooner at a median 8 weeks (interquartile range [IQR], 4, 12) versus 12 weeks (IQR, 8, 18; University of Chicago P=0.02) and had a lower pill burden of 240 (IQR, 180, 298) versus 292 (IQR, 231, 405; P=0.01). Confirmed hy- Pritzker School of percalcemia was very low in both groups (three with paricalcitol and one with calcitriol) and was not significantly Medicine, Evanston, different (P=0.36). Both groups had small increases in calcium and phosphorus levels (0.3–0.4 mg/dl in each Illinois electrolyte) and significant decreases in alkaline phosphatase, a marker of high bone turnover, with no significant differences between groups. Correspondence: Dr.DanielW.Coyne, School of Medicine, Conclusions These results show that both calcitriol and paricalcitol achieved sustained PTH and alkaline Washington phosphatase suppression in stages 3–4 CKD, with small effects on serum calcium and phosphorus and a low University in St. Louis, incidence of hypercalcemia. 660 S. Euclid Avenue, Clin J Am Soc Nephrol ccc–ccc Campus Box 8129, St. 9: , 2014. doi: 10.2215/CJN.10661013 Louis, MO 63110. Email: DCoyne@dom. wustl.edu Introduction In addition to activating the vitamin D receptors Secondary hyperparathyroidism (SHPT) is common in (VDRs) in the parathyroid gland, calcitriol also activates patients with CKD, and is characterized by a progressive the VDR in other tissues, including intestine and bone increase in parathyroid hormone (PTH) and growth of (9). Administration of calcitriol or its analogs requires the parathyroid glands (1,2). A major factor in the de- regular monitoring of serum calcium and phosphorus velopment and progression of SHPT is the steady de- levels (9). Induction of hypercalcemia or hyperphospha- cline in serum calcitriol levels, the active form of temia can limit the dose of VDRA administered, thereby vitamin D (1). The incidence and severity of SHPT in- limiting its efficacy for PTH suppression. creases as renal function worsens, with 35% of patients In preclinical studies, at comparable PTH-suppressing with stage 3 CKD and 70% of patients with stage 4 doses, paricalcitol causes a significantly smaller increase CKD carrying this diagnosis (1). in serum calcium and phosphorus levels than calcitriol Exogenous administration of vitamin D receptor (10,11). Crossover trials of these agents in hemodialysis activators (VDRAs), such as calcitriol or the analogs patients have also demonstrated less intestinal calcium paricalcitol, doxercalciferol, and alfacalcidol, suppres- absorption and less stimulation of bone resorption with ses PTH levels but can increase serum calcium and paricalcitol compared with calcitriol (12,13). These dif- phosphorus (3–5). Major renal guidelines recommend ferences are thought to be the result of less activation of use of active vitamin D for SHPT in stages 3–4 CKD, the intestinal and bone VDRs by paricalcitol. Two ran- but comparison of different VDRAs in this population domized trials comparing calcitriol with paricalcitol in has been limited (6–8). hemodialysis patients have shown mixed results, with www.cjasn.org Vol 9 September, 2014 Copyright © 2014 by the American Society of Nephrology 1 2 Clinical Journal of the American Society of Nephrology one trial reporting significantly less hypercalcemia and eleva- random sequence was computer generated and site specific tion of calcium–phosphate product with paricalcitol despite without stratification. Sequentially numbered opaque sealed somewhat superior PTH suppression, whereas a smaller envelopes were provided to each site, with the next available study showed no significant differences between agents (3,4). envelope opened after the patient was confirmed to meet all In three placebo-controlled trials in patients with stages inclusion and exclusion criteria. Patients each had their own 3–4 CKD with SHPT, paricalcitol suppressed PTH by 42% PTH target goal of 40%–60% below their baseline PTH mea- at 6 months and caused hypercalcemia in 2% versus 0% of surement. Dose adjustments were based on laboratory patients who received placebo (14). A small trial of calci- results at each visit (weeks 4, 8, 12, and 18). Albumin-corrected triol using doses of #0.5 mg/d reported that eight of 15 calcium (cCa) was calculated as follows: {serum calcium+[(4– patients with CKD became hypercalcemic at least once serum albumin)30.8]} if albumin was ,4.0 g/dl. The dose during an 8-month treatment period (15). was titrated up at any visit if PTH was suppressed ,40% Given the limited comparative data in patients with CKD from baseline and cCa was ,10.5 mg/dl. Dose increases with these agents, we performed a multicenter, open-label were conducted in the following manner: one capsule alter- randomized trial to compare the incidence of hypercalce- nating with two capsules daily, then two capsules daily, then mia in patients treated with paricalcitol and calcitriol for three capsules daily, and then four capsules daily. Maximum SHPT. The clinical goal was to suppress and maintain PTH possible doses were 4 mg/d paricalcitol or 1 mg/d calcitriol. concentrations at 40%–60% below the mean pretreatment Dosing was reduced one step if the PTH was suppressed by PTH value, and the primary endpoint was the difference in .60% from baseline; if the patient was already on the initial the incidence of hypercalcemia in each arm. step of one capsule daily, the dose was reduced to one cap- sule every other day. If the cCa was $10.5 mg/dl, a confir- matory test was obtained as soon as possible but at least Materials and Methods 1 day later; if hypercalcemia was verified, the dose was re- Study Design and Oversight duced by one step. Consistent with clinical practice, the use of The Paricalcitol and Calcitriol Endpoints study (Clinical- dietary phosphorus restriction or phosphorus binders were Trials.gov registry number NCT00823303) is an open-label, encouraged if hyperphosphatemia (.4.6 mg/dl) developed. active comparator, multicenter, parallel group, phase 4 study Study participation was over a 24-week period with active of paricalcitol versus calcitriol for suppression of PTH in medication, with a 1-week follow-up. stages 3–4 CKD. The trial was conducted at four sites in the United States and was approved by each institutional re- Endpoints view board. The trial design was investigator-initiated and The primary endpoint was the difference in the percentage was funded by Abbott, now AbbVie (Abbott Park, IL). Ab- of patients in each group developing a confirmed hypercal- bott was not involved in the design or conduct of the trial, cemic event ($10.5 mg/dl). The prespecified secondary ob- but was able to review the manuscript before submission. jectives were to evaluate the differences between treatment The four trial sites were Washington University in St. Louis groups in changes in serum calcium, incidence of hyper- (St. Louis, MO), Henry Ford Hospital (Detroit, MI), North- phosphatemia, change in serum phosphorus, change in al- western University (Chicago, IL), and the Northshore Uni- kaline phosphatase, percentage of patients achieving .40% versity Health System (Evanston, IL). PTH suppression, and mean PTH suppression. The primary – Eligible patients had stages 3 4 CKD and known or sus- endpoint was also the primary safety endpoint. Adverse . pected SHPT. Inclusion criteria were aged 18 years, a stable events were also evaluated. dose of phosphate binder (if receiving a binder), eGFR of 15– 2 fi 59 ml/min per 1.73 m using the abbreviated Modi cation Statistical Analyses . of Diet in Renal Disease equation, PTH 120 pg/ml, albumin- The primary predefined analysis was based on an intention- . , corrected calcium 8.5 mg/dl and 10.0 mg/dl, and phos- to-treat analysis, which includes participants who received at , phorus 4.6 mg/dl. Exclusion criteria were history of least one study treatment and had at least one postbaseline . primary hyperparathyroidism, prednisone use for 30 calcium determination. Secondary endpoints were also asses- days within the previous 6 months, administration of bi- sed on an intention-to-treat basis. On the basis of prior pub- sphosphonates or calcitonin within the previous 12 months, lished reports, we estimated a 5% rate of hypercalcemia with recent hospitalization, an expected need for dialysis or paricalcitol and a 30% rate with calcitriol (15,16).