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INTRODUCTION: Chronic kidney disease (CKD) drives onerous human and healthcare costs, underscoring an urgent need to avert disease progression. Secondary hyperparathyroidism (SHPT) develops as CKD advances, and persistently elevated parathyroid hormone (PTH) may be nephrotoxic and associated with earlier dialysis onset. This study examines, for the first time, the hypothesis that sustained reduction of elevated intact PTH (iPTH) with extended-release calcifediol (ERC) reduces the nephrotoxic impact of SHPT and forestalls renal decline. METHODS: Changes in estimated glomerular filtration rate (eGFR) were analyzed post-hoc in 126 adults with SHPT, stage 3-4 CKD and low serum 25-hydroxyvitamin D (25D) treated for one year with ERC in pivotal trials. ERC was administered at 30 µg/day increasing, as needed, to 60 µg/day to achieve ≥30% reductions in iPTH. Calcium, phosphorus, 25D, 1,25-dihydroxyvitamin D (1,25D), iPTH, eGFR, fibroblast growth factor 23 (FGF23), bone turnover markers (BTM), and urine albumin-to-creatinine ratio (uACR) were measured at baseline (BL) and regular intervals. Participants were categorized by achievement (or not) of sustained ≥30% iPTH reductions over the last 2 quarters of treatment to evaluate differences in eGFR decline. RESULTS: For all participants, 25D increased 58.5±2.3 (SE) ng/mL (p<0.001) by the end of treatment (EOT), 1,25D increased 10.1±1.8 pg/mL (p<0.001), iPTH decreased from 143.8±5.8 pg/mL to 108.8±7.2 (p<0.001), BTMs improved (p<0.01) and eGFR declined 2.2±0.5 mL/min/1.73m2 (p<0.001). The rate of eGFR decline was >5-fold higher (p=0.014) in participants who did not achieve sustained iPTH reductions of ≥30% (3.2±0.7; 12.7±2.2%) than in those who did (0.6±0.8; 2.9±2.4%). It was highest in the 30 participants who did not exhibit an iPTH lowering response in both of the last 2 quarters of treatment (5.4±0.9; 20.9±3.4%). Duration of iPTH reduction had no impact on safety parameters. Degree of iPTH reduction at EOT was also associated with slower CKD progression. CONCLUSION: Sustained reduction of elevated iPTH with ERC treatment was associated with slower rates of eGFR decline in patients with SHPT and stage 3-4 CKD without raising safety concerns. A prospective trial is warranted to confirm this finding.
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Introduction: Parathyroid hormone-lowering responses after administration of three different therapies capable of raising serum total 25-hydroxyvitamin D (25OHD) were evaluated in patients with secondary hyperparathyroidism (SHPT), vitamin D insufficiency (VDI), and stage 3 or 4 chronic kidney disease (CKD). Methods: Sixty-nine adult subjects with intact parathyroid hormone (iPTH) ≥85 and <500 pg/mL and VDI (25OHD <30 ng/mL) were randomized after ≥4-week washout to 2 months of open-label treatment with: (1) extended-release calcifediol (ERC) 60 µg/day; (2) immediate-release calcifediol (IRC) 266 µg/month; (3) high-dose cholecalciferol (HDC) 300,000 IU/month; or (4) paricalcitol plus low-dose cholecalciferol (PLDC) 1 or 2 µg and 800 IU/day, used as reference hormone replacement therapy. Serum 25OHD, calcium (Ca), phosphorus (P), plasma iPTH, and adverse events were monitored weekly. No clinically significant differences were observed at baseline between treatment groups. Results: Sixty-two subjects completed the study per protocol (PP; 14-17 per group). Mean (SD) 25OHD and iPTH at baseline were 20.6 (6.6) ng/mL and 144.8 (90) pg/mL, respectively. Mean 25OHD increased at end of treatment (EOT) to 82.9 (17.0) ng/mL with ERC (p < 0.001) and 30.8 (11.6) ng/mL with HDC (p < 0.05), but remained unchanged with IRC and PLDC. EOT 25OHD levels reached ≥30 ng/mL in all subjects treated with ERC and in 44% with HDC. All subjects attained EOT 25OHD levels ≥50 ng/mL with ERC versus none with other therapies. iPTH response rates at EOT (≥10, 20 or 30% below baseline) were similar for ERC and PLDC; rates for IRC and HDC were much lower. No significant changes from baseline were observed in ionized or corrected total Ca or P in any group. One episode of hypercalcemia (>10.3 mg/dL) occurred with PLDC. Hyperphosphatemia (>5.5 mg/dL) occurred once with ERC, eight times with HDC, 3 times with IRC, and twice with PLDC. Conclusion: ERC was highly effective in both raising serum 25OHD and decreasing iPTH in patients with SHPT, VDI, and stage 3 or 4 CKD. iPTH-lowering response rates with ERC were similar to daily PLDC, the reference therapy; rates with IRC or HDC were significantly lower. ERC is an attractive alternative to vitamin D hormone therapy in CKD patients.
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Little is known about the most important factors that inform a nephrologist's decision to treat (DTT) pre-dialysis chronic kidney disease (CKD) patients with vitamin D insufficiency (VDI) and secondary hyperparathyroidism (SHPT). The objective of this study was to identify such factors and their relative importance in the DTT with a vitamin D therapy. A web-based, adaptive design conjoint analysis discrete-choice survey was developed to study factors that informed the DTT among a sample of 200 nephrologists located throughout the United States. Based on literature review and clinician input, eight attributes were selected that could influence a provider's DTT: age, race, CKD stage, serum 25-hydroxyvitamin D (25D), parathyroid hormone (PTH), serum calcium (Ca), serum phosphorus (P), and history of comorbidities. Respondents were asked to select one patient profile most suitable for treatment from three profiles with varying attribute levels. Each attribute's relative importance score was computed using hierarchical-Bayesian statistics to measure the influence of each factor where higher scores represented greater DTT consideration. The pooled analysis revealed the four most important factors: serum 25D (31.4%), serum Ca (22.7%), plasma PTH (11.5%) levels, and history of comorbidities (8.5%). Age (8.2%), serum P (7.7%), CKD stage (5.7%), and race (4.4%) were relatively less important. Patients' 25D and Ca levels contributed to more than half of nephrologists' DTT, with the consideration of PTH levels being less of a factor. Further understanding of the driving forces behind the factors that inform the DTT may help to standardize the management of CKD patients with SHPT and VDI and improve outcomes.
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Hiperparatiroidismo Secundario , Insuficiencia Renal Crónica , Deficiencia de Vitamina D , Humanos , Estados Unidos , Nefrólogos , Teorema de Bayes , Diálisis , Vitamina D , Vitaminas/uso terapéutico , Insuficiencia Renal Crónica/terapia , Hormona Paratiroidea , Deficiencia de Vitamina D/complicaciones , CalcioRESUMEN
OBJECTIVES: This double-blind randomized controlled trial investigated raising serum 25-hydroxyvitamin D (25D) with extended-release calcifediol (ERC) on time to symptom resolution in patients with mild to moderate COVID-19. METHODS: COVID-19 outpatients received oral ERC (300 mcg on days 1-3 and 60 mcg on days 4-27) or placebo (NCT04551911). Symptoms were self-reported daily. Primary end points were raising 25D to ≥50 ng/mL and decreasing resolution time for five aggregated symptoms (three respiratory). RESULTS: In all, 171 patients were randomized, 160 treated and 134 (65 ERC, 69 placebo) retained. The average age was 43 y (range 18-71), 59% were women. The mean baseline 25D was 37 ± 1 (SE) ng/mL. In the full analysis set (FAS), 81% of patients in the ERC group achieved 25D levels of ≥50 ng/mL versus 15% in the placebo group (P < 0.0001). In the per-protocol (PP) population, mean 25D increased with ERC to 82 ± 4 (SE) ng/mL (P < 0.0001) by day 7; the placebo group trended lower. Symptom resolution time was unchanged in the FAS by ERC (hazard ratio [HR], 0.983; 95% confidence interval [CI], 0.695-1.390; P = 0.922). In the PP population, respiratory symptoms resolved 4 d faster when 25D was elevated above baseline level at both days 7 and 14 (median 6.5 versus 10.5 d; HR, 1.372; 95% CI, 0.945-1.991; P = 0.0962; Wilcoxon P = 0.0386). Symptoms resolved in both treatment groups to a similar extent by study end. Safety concerns including hypercalcemia were absent with ERC treatment. CONCLUSION: ERC safely raised serum 25D to ≥50 ng/mL in outpatients with COVID-19, possibly accelerating resolution of respiratory symptoms and mitigating the risk for pneumonia. These findings warrant further study.
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COVID-19 , Deficiencia de Vitamina D , Humanos , Femenino , Adulto , Masculino , Calcifediol , Pacientes Ambulatorios , Método Doble Ciego , Resultado del TratamientoRESUMEN
INTRODUCTION: Extended-release calcifediol (ERC), active vitamin D hormones and analogs (AVD) and nutritional vitamin D (NVD) are commonly used therapies for treating secondary hyperparathyroidism (SHPT) in adults with stage 3-4 chronic kidney disease (CKD) and vitamin D insufficiency (VDI). Their effectiveness for increasing serum total 25-hydroxyvitamin D (25D) and reducing elevated plasma parathyroid hormone (PTH), the latter of which is associated with increased morbidity and mortality, has varied across controlled clinical trials. This study aimed to assess real-world experience of ERC and other vitamin D therapies in reducing PTH and increasing 25D. METHODS: Medical records of 376 adult patients with stage 3-4 CKD and a history of SHPT and VDI from 15 United States (US) nephrology clinics were reviewed for up to 1 year pre- and post-ERC, NVD or AVD initiation. Key study variables included patient demographics, concomitant usage of medications and laboratory data. The mean age of the study population was 69.5 years, with gender and racial distributions representative of the US CKD population. Enrolled patients were grouped by treatment into three cohorts: ERC (n = 174), AVD (n = 55) and NVD (n = 147), and mean baseline levels were similar for serum 25D (18.8-23.5 ng/mL), calcium (Ca: 9.1-9.3 mg/dL), phosphorus (P: 3.7-3.8 mg/dL) and estimated glomerular filtration rate (eGFR: 30.3-35.7 mL/min/1.73m2). Mean baseline PTH was 181.4 pg/mL for the ERC cohort versus 156.9 for the AVD cohort and 134.8 pg/mL (p < 0.001) for the NVD cohort. Mean follow-up during treatment ranged from 20.0 to 28.8 weeks. RESULTS: Serum 25D rose in all cohorts (p < 0.001) during treatment. ERC yielded the highest increase (p < 0.001) of 23.7 ± 1.6 ng/mL versus 9.7 ± 1.5 and 5.5 ± 1.3 ng/mL for NVD and AVD, respectively. PTH declined with ERC treatment by 34.1 ± 6.6 pg/mL (p < 0.001) but remained unchanged in the other two cohorts. Serum Ca increased 0.2 ± 0.1 pg/mL (p < 0.001) with AVD but remained otherwise stable. Serum alkaline phosphatase remained unchanged. CONCLUSIONS: Real-world clinical effectiveness and safety varied across the therapies under investigation, but only ERC effectively raised mean 25D (to well above 30 ng/mL) and reduced mean PTH levels without causing hypercalcemia.
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Hiperparatiroidismo Secundario , Insuficiencia Renal Crónica , Adulto , Humanos , Anciano , Calcifediol/uso terapéutico , Vitamina D , Hiperparatiroidismo Secundario/tratamiento farmacológico , Hiperparatiroidismo Secundario/etiología , Vitaminas/uso terapéutico , Hormona Paratiroidea , Insuficiencia Renal Crónica/tratamiento farmacológico , Insuficiencia Renal Crónica/epidemiología , CalcioRESUMEN
INTRODUCTION: Obesity increases the risk of vitamin D insufficiency, which exacerbates secondary hyperparathyroidism in chronic kidney disease. Recent studies suggest that serum total 25-hydroxyvitamin D (25OHD) levels of ≥50 ng/mL are necessary to produce significant reductions in elevated parathyroid hormone levels in nondialysis patients. Data from real-world and randomized controlled trials (RCTs) involving these patients were examined for (1) relationships between vitamin D treatments and the achieved levels of serum 25OHD and between serum 25OHD and body weight (BW)/body mass index (BMI); and (2) the impact of BW/BMI on achieving serum 25OHD levels ≥50 ng/mL with extended-release calcifediol (ERC) treatment or vitamin D supplementation (cholecalciferol or ergocalciferol). METHODS: Data obtained from nondialysis patients participating in two real-world studies, one conducted in Europe (Study 1) and the other (Study 2) in the USA, and in two US RCTs (Studies 3 and 4) were analyzed for serum 25OHD outcomes after treatment with ERC, vitamin D supplements, or placebo. RESULTS: More than 50% of subjects treated with vitamin D supplements in both real-world studies (Studies 1 and 2) failed to achieve serum 25OHD levels ≥30 ng/mL, a level widely viewed by nephrologists as the threshold of adequacy; only 7.3-7.5% of subjects achieved levels ≥50 ng/mL. Data from the European study (Study 1) showed that serum 25OHD levels had significant and nearly identical inverse relationships with BW and BMI, indicating that high BW or BMI thwarts the ability of vitamin D supplements to raise serum 25OHD. One RCT (Study 3) showed that 8 weeks of ERC treatment (60 µg/day) raised serum 25OHD levels to ≥30 and 50 ng/mL in all subjects, regardless of BW, while cholecalciferol (300,000 IU/month) raised serum 25OHD to these thresholds in 56% and 0% of subjects, respectively. The other RCT (Study 4) showed that ERC treatment (30 or 60 µg/day) successfully raised mean serum 25OHD levels to at least 50 ng/mL for subjects in all BW categories, whereas no increases were observed with placebo treatment. CONCLUSION: Real-world studies conducted in Europe and USA in nondialysis patients (Studies 1 and 2) showed that vitamin D supplements (cholecalciferol or ergocalciferol) were unreliable in raising serum total 25OHD to targets of 30 or 50 ng/mL. In contrast, ERC was demonstrated to be effective in one real-world study (Study 2) and two RCTs (Studies 3 and 4) conducted in US nondialysis patients in raising serum 25OHD to these targeted levels irrespective of BW.
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Hiperparatiroidismo Secundario , Insuficiencia Renal Crónica , Deficiencia de Vitamina D , Calcifediol , Colecalciferol/uso terapéutico , Ergocalciferoles/uso terapéutico , Humanos , Hiperparatiroidismo Secundario/complicaciones , Hiperparatiroidismo Secundario/etiología , Sobrepeso/complicaciones , Sobrepeso/tratamiento farmacológico , Hormona Paratiroidea , Ensayos Clínicos Controlados Aleatorios como Asunto , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/tratamiento farmacológico , Vitamina D/análogos & derivados , Deficiencia de Vitamina D/complicaciones , Deficiencia de Vitamina D/tratamiento farmacológico , Vitaminas/uso terapéuticoRESUMEN
INTRODUCTION: The safety and efficacy of extended-release calcifediol (ERC) as a treatment for secondary hyperparathyroidism (SHPT) in adults with stage 3 or 4 chronic kidney disease (CKD) and vitamin D insufficiency (VDI) has been demonstrated in prospective randomized clinical trials (RCTs). ERC (Rayaldee®) was approved by the Food and Drug Administration in 2016 on the basis of these prospective RCTs. The current retrospective study assessed the postlaunch data available with respect to ERC's efficacy and safety in increasing serum 25-hydroxyvitamin D (25D) and reducing parathyroid hormone (PTH) in the indicated population. MATERIALS AND METHODS: Medical records of 174 patients who met study criteria from 15 geographically representative United States nephrology clinics were reviewed for 1 year before and after initiation of ERC treatment. Enrolled subjects had ages ≥18 years, stage 3 or 4 CKD, and a history of SHPT and VDI. Key study variables included patient demographics, medication usage, and laboratory results, including serial 25D and PTH determinations. RESULTS: The enrolled subjects had a mean age of 69.0 years, gender and racial distributions representative of the indicated population, and were balanced for CKD stage. Most (98%) received 30 mcg of ERC/day during the course of treatment (mean follow-up: 24 weeks). Baseline 25D and PTH levels averaged 20.3 ± 0.7 (standard error) ng/mL and 181 ± 7.4 pg/mL, respectively. ERC treatment raised 25D by 23.7 ± 1.6 ng/mL (p < 0.001) and decreased PTH by 34.1 ± 6.6 pg/mL (p < 0.001) with nominal changes of 0.1 mg/dL (p > 0.05) in serum calcium (Ca) and phosphorus (P) levels. DISCUSSION/CONCLUSION: Analysis of postlaunch data confirmed ERC's effectiveness in increasing serum 25D and reducing PTH levels without statistically significant or notable impact on serum Ca and P levels. A significant percentage of these subjects achieved 25D levels ≥30 mg/mL and PTH levels which decreased by at least 30% from baseline. Dose titration to 60 mcgs was rarely prescribed. Closer patient monitoring and appropriate dose titration may have led to a higher percentage of subjects achieving an increase in 25D levels to at least 50 ng/mL and a reduction in PTH levels of at least 30%.
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Calcifediol/uso terapéutico , Hiperparatiroidismo Secundario/tratamiento farmacológico , Vitaminas/uso terapéutico , Anciano , Anciano de 80 o más Años , Calcifediol/efectos adversos , Preparaciones de Acción Retardada , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento , Vitaminas/efectos adversosRESUMEN
BACKGROUND: Vitamin D repletion is recommended for secondary hyperparathyroidism (SHPT) and associated vitamin D insufficiency (VDI) in chronic kidney disease (CKD), but optimal levels of serum total 25-hydroxyvitamin D remain undefined. Clinical practice guidelines target sufficiency, whereas recent data indicate that higher levels are required to control the elevation of intact parathyroid hormone (iPTH) as CKD advances. This secondary analysis of 2 randomized controlled trials seeks to identify the minimum level of mean serum 25-hydroxyvitamin D required to control SHPT arising from VDI in stage 3 or 4 CKD. METHODS: Adult subjects (n = 429) with SHPT, VDI, and stage 3 or 4 CKD were stratified by stage and treated daily with either extended-release calcifediol (ERC) or placebo in 2 identical, parallel, randomized, double-blind studies. After treatment for 26 weeks, all subjects were ranked by the level of serum total 25-hydroxyvitamin D and divided into quintiles in order to examine the relationships between the degree of vitamin D repletion and the associated changes in plasma iPTH, serum bone turnover markers, calcium, phosphorus, intact fibroblast growth factor 23 (FGF23) and vitamin D metabolites, estimated glomerular filtration rate (eGFR), and urine calcium:creatinine (Ca:Cr) ratio. RESULTS: Progressive increases in serum 1,25-dihydroxyvitamin D and reductions in plasma iPTH and serum bone turnover markers were observed as mean posttreatment serum 25-hydroxyvitamin D rose from 13.9 ng/mL (in Quintile 1) to 92.5 ng/mL (in Quintile 5), irrespective of CKD stage. Mean serum calcium, phosphorus and FGF23, eGFR, and urine Ca:Cr ratio (collectively "safety parameters") did not significantly change from Quintile 1. Suppression of iPTH and bone turnover markers was not observed until serum 25-hydroxyvitamin D rose to at least 50.8 ng/mL (Quintile 3). CONCLUSION: ERC therapy produced exposure-dependent reductions in plasma iPTH and bone turnover markers only when mean serum total 25-hydroxyvitamin D reached at least 50.8 ng/mL, indicating that current targets for vitamin D repletion therapy in CKD are too low. Gradual elevation of mean serum 25-hydroxyvitamin D to 92.5 ng/mL was not associated with significant adverse changes in safety parameters.
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Calcifediol/administración & dosificación , Hiperparatiroidismo Secundario/tratamiento farmacológico , Insuficiencia Renal Crónica/complicaciones , Deficiencia de Vitamina D/tratamiento farmacológico , Vitamina D/análogos & derivados , Anciano , Método Doble Ciego , Monitoreo de Drogas/normas , Femenino , Factor-23 de Crecimiento de Fibroblastos , Humanos , Hiperparatiroidismo Secundario/sangre , Hiperparatiroidismo Secundario/diagnóstico , Hiperparatiroidismo Secundario/etiología , Masculino , Persona de Mediana Edad , Hormona Paratiroidea/sangre , Guías de Práctica Clínica como Asunto , Valores de Referencia , Insuficiencia Renal Crónica/sangre , Vitamina D/sangre , Deficiencia de Vitamina D/sangre , Deficiencia de Vitamina D/diagnóstico , Deficiencia de Vitamina D/etiologíaRESUMEN
INTRODUCTION: Extended-release calcifediol (ERC) 30 µg capsules were recently approved as Rayaldee® by the United States Food and Drug Administration (FDA) for the treatment of secondary hyperparathyroidism (SHPT) in adults with stage 3-4 (not 5) chronic kidney disease (CKD) and vitamin D insufficiency (serum total 25-hydroxyvitamin D < 30 ng/mL). Calcifediol is 25-hydroxyvitamin D3, a prohormone of calcitriol (1,25-dihydroxyvitamin D3), the endogenous active vitamin D hormone. ERC capsules have a lipophilic fill which gradually releases calcifediol, corrects vitamin D insufficiency and increases serum calcitriol and thereby suppresses production of parathyroid hormone (PTH) in CKD patients without perturbing normal vitamin D and mineral metabolism. Areas covered: This review focuses on the chemical, pharmacokinetic, pharmacodynamic and clinical profiles of ERC and describes the product's utility relative to other current treatment options for SHPT. Expert commentary: Randomized clinical trials (RCTs) have demonstrated that nutritional vitamin D is ineffective for treating SHPT whereas vitamin D receptor activators can correct elevated PTH but with increased risk of hypercalcemia and hyperphosphatemia. ERC offers healthcare professionals a new treatment option that has been demonstrated in RCTs to be safe and effective for controlling SHPT without meaningfully increasing serum concentrations of calcium or phosphorus.
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BACKGROUND/AIMS: Vitamin D insufficiency and secondary hyperparathyroidism (SHPT) are associated with increased morbidity and mortality in chronic kidney disease (CKD) and are poorly addressed by current treatments. The present clinical studies evaluated extended-release (ER) calcifediol, a novel vitamin D prohormone repletion therapy designed to gradually correct low serum total 25-hydroxyvitamin D, improve SHPT control and minimize the induction of CYP24A1 and FGF23. METHODS: Two identical multicenter, randomized, double-blind, placebo-controlled studies enrolled subjects from 89 US sites. A total of 429 subjects, balanced between studies, with stage 3 or 4 CKD, SHPT and vitamin D insufficiency were randomized 2:1 to receive oral ER calcifediol (30 or 60 µg) or placebo once daily at bedtime for 26 weeks. Most subjects (354 or 83%) completed dosing, and 298 (69%) entered a subsequent open-label extension study wherein ER calcifediol was administered without interruption for another 26 weeks. RESULTS: ER calcifediol normalized serum total 25-hydroxyvitamin D concentrations (>30 ng/ml) in >95% of per-protocol subjects and reduced plasma intact parathyroid hormone (iPTH) by at least 10% in 72%. The proportion of subjects receiving ER calcifediol who achieved iPTH reductions of ≥30% increased progressively with treatment duration, reaching 22, 40 and 50% at 12, 26 and 52 weeks, respectively. iPTH lowering with ER calcifediol was independent of CKD stage and significantly greater than with placebo. ER calcifediol had inconsequential impact on serum calcium, phosphorus, FGF23 and adverse events. CONCLUSION: Oral ER calcifediol is safe and effective in treating SHPT and vitamin D insufficiency in CKD.
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Calcifediol/uso terapéutico , Hiperparatiroidismo/tratamiento farmacológico , Insuficiencia Renal Crónica/complicaciones , Deficiencia de Vitamina D/tratamiento farmacológico , Vitaminas/uso terapéutico , 24,25-Dihidroxivitamina D 3/sangre , Anciano , Calcifediol/efectos adversos , Calcio/sangre , Calcio/orina , Creatinina/orina , Preparaciones de Acción Retardada/uso terapéutico , Método Doble Ciego , Femenino , Factor-23 de Crecimiento de Fibroblastos , Factores de Crecimiento de Fibroblastos/sangre , Tasa de Filtración Glomerular , Humanos , Hiperparatiroidismo/sangre , Hiperparatiroidismo/etiología , Masculino , Persona de Mediana Edad , Hormona Paratiroidea/sangre , Fósforo/sangre , Insuficiencia Renal Crónica/fisiopatología , Vitamina D/análogos & derivados , Vitamina D/sangre , Deficiencia de Vitamina D/sangre , Deficiencia de Vitamina D/etiología , Vitaminas/efectos adversosRESUMEN
Vitamin D insufficiency is prevalent in chronic kidney disease (CKD) and associated with secondary hyperparathyroidism (SHPT) and increased risk of bone and vascular disease. Unfortunately, supplementation of stage 3 or 4 CKD patients with currently recommended vitamin D2 or D3 regimens does not reliably restore serum total 25-hydroxyvitamin D to adequacy (≥30ng/mL) or effectively control SHPT. Preclinical and clinical studies were conducted to evaluate whether the effectiveness of vitamin D repletion depends, at least in part, on the rate of repletion. A modified-release (MR) oral formulation of calcifediol (25-hydroxyvitamin D3) was developed which raised serum 25-hydroxyvitamin D3 and calcitriol levels gradually. Single doses of either bolus intravenous (IV) or oral MR calcifediol were administered to vitamin D deficient rats. Bolus IV calcifediol produced rapid increases in serum 25-hydroxyvitamin D3, calcitriol and FGF23, along with significant induction of CYP24A1 in both kidney and parathyroid gland. In contrast, oral MR calcifediol produced gradual increases in serum 25-hydroxyvitamin D3 and calcitriol and achieved similar hormonal exposure, yet neither CYP24A1 nor FGF23 were induced. A 10-fold greater exposure to bolus IV than oral MR calcifediol was required to similarly lower intact parathyroid hormone (iPTH). Single doses of oral MR (450 or 900µg) or bolus IV (450µg) calcifediol were administered to patients with stage 3 or 4 CKD, SHPT and vitamin D insufficiency. Changes in serum 25-hydroxyvitamin D3 and calcitriol and in plasma iPTH were determined at multiple time-points over the following 42 days. IV calcifediol produced abrupt and pronounced increases in serum 25-hydroxyvitamin D3 and calcitriol, but little change in plasma iPTH. As in animals, these surges triggered increased vitamin D catabolism, as evidenced by elevated production of 24,25-dihydroxyvitamin D3. In contrast, MR calcifediol raised serum 25-hydroxyvitamin D3 and calcitriol gradually, and meaningfully lowered plasma iPTH levels. Taken together, these studies indicate that rapid increases in 25-hydroxyvitamin D3 trigger CYP24A1 and FGF23 induction, limiting effective exposure to calcitriol and iPTH reduction in SHPT. They also support further investigation of gradual vitamin D repletion for improved clinical effectiveness. This article is part of a Special Issue entitled "17th Vitamin D Workshop".
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Calcifediol/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Insuficiencia Renal Crónica/tratamiento farmacológico , Deficiencia de Vitamina D/prevención & control , Vitaminas/farmacología , 24,25-Dihidroxivitamina D 3/sangre , 25-Hidroxivitamina D3 1-alfa-Hidroxilasa/genética , Administración Oral , Animales , Calcio/sangre , Suplementos Dietéticos , Liberación de Fármacos , Factor-23 de Crecimiento de Fibroblastos , Factores de Crecimiento de Fibroblastos/sangre , Humanos , Masculino , Hormona Paratiroidea/sangre , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Insuficiencia Renal Crónica/metabolismo , Deficiencia de Vitamina D/metabolismo , Vitamina D3 24-Hidroxilasa/genéticaRESUMEN
BACKGROUND/AIMS: Vitamin D insufficiency drives secondary hyperparathyroidism (SHPT) and is associated with increased cardiovascular mortality in patients with chronic kidney disease (CKD). SHPT is poorly addressed by current vitamin D repletion options. The present study evaluated a novel investigational vitamin D repletion therapy: a modified-release (MR) formulation of calcifediol designed to raise serum 25-hydroxyvitamin D in a gradual manner to minimize the induction of CYP24 and, thereby, improve the SHPT control. METHODS: This randomized, double-blind, placebo-controlled trial evaluated MR calcifediol in CKD subjects (n = 78) with plasma intact parathyroid hormone (iPTH) >70 pg/ml and serum total 25-hydroxyvitamin D <30 ng/ml. Subjects received daily treatment for six weeks with oral MR calcifediol (30, 60 or 90 µg) or a placebo. RESULTS: More than 90% of subjects treated with MR calcifediol achieved serum 25-hydroxyvitamin D levels ≥30 ng/ml versus 3% of subjects treated with placebo (p < 0.0001). Mean plasma iPTH decreased from baseline (140.3 pg/ml) by 20.9 ± 6.2% (SE), 32.8 ± 5.7 and 39.3 ± 4.3% in the 30, 60 and 90 µg dose groups, respectively, and increased 17.2 ± 7.8% in the pooled placebo group (p < 0.005). No clinically significant safety concerns arose during MR calcifediol treatment. CONCLUSION: Oral MR calcifediol appears safe and highly effective in treating SHPT associated with vitamin D insufficiency in CKD.
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Calcifediol/administración & dosificación , Hiperparatiroidismo Secundario/tratamiento farmacológico , Insuficiencia Renal Crónica/complicaciones , Deficiencia de Vitamina D/tratamiento farmacológico , Vitamina D/análogos & derivados , Vitaminas/administración & dosificación , Adulto , Anciano , Calcifediol/sangre , Preparaciones de Acción Retardada , Método Doble Ciego , Femenino , Humanos , Hiperparatiroidismo Secundario/sangre , Hiperparatiroidismo Secundario/etiología , Masculino , Persona de Mediana Edad , Hormona Paratiroidea/sangre , Insuficiencia Renal Crónica/sangre , Vitamina D/sangre , Deficiencia de Vitamina D/sangre , Deficiencia de Vitamina D/etiología , Vitaminas/sangreRESUMEN
BACKGROUND: Calcitriol lowers parathyroid hormone (PTH) levels in patients with chronic kidney disease (CKD) stages 3 and 4, but its use is limited by a low therapeutic index and concerns regarding hypercalcemia and acceleration of kidney disease. We evaluated doxercalciferol (1alpha-hydroxyvitamin D2) as an alternative therapy in a randomized, double-blinded, placebo-controlled, multicenter trial. METHODS: Fifty-five adults with stage 3 or 4 CKD and an intact PTH (iPTH) level greater than 85 pg/mL (ng/L) completed 8 baseline weeks, followed by 24 weeks of oral therapy with doxercalciferol or placebo. Pretreatment demographics and biochemical features did not differ between groups. Dosages were increased gradually if iPTH level was not decreased by 30% or greater and serum calcium and phosphorus levels were stable. Regular monitoring included plasma iPTH, serum calcium and phosphorus, urinary calcium, bone-specific serum markers, and serum lalpha,25-dihydroxyvitamin D levels. Glomerular filtration rate (GFR) was measured before and after treatment. RESULTS: Mean plasma iPTH level decreased by 46% from baseline after 24 weeks of doxercalciferol treatment (P <0.001), but was unchanged with placebo. After 6 weeks, iPTH level reductions with doxercalciferol treatment exceeded those with placebo at all subsequent intervals (P <0.001). No clinically significant differences in mean serum calcium or phosphorus or urinary calcium levels or incidence of hypercalcemia, hyperphosphatemia, or hypercalciuria were noted between groups. Serum C- and N-telopeptide and bone-specific alkaline phosphatase levels decreased with doxercalciferol treatment relative to both baseline and placebo (P <0.01). Adverse-event rates and changes in GFR did not differ between groups. CONCLUSION: Doxercalciferol is safe and effective in controlling secondary hyperparathyroidism of patients with CKD stages 3 and 4.
Asunto(s)
Ergocalciferoles/uso terapéutico , Hiperparatiroidismo Secundario/tratamiento farmacológico , Hiperparatiroidismo Secundario/etiología , Enfermedades Renales/complicaciones , Hormona Paratiroidea/sangre , Anciano , Calcio/sangre , Calcio/orina , Enfermedad Crónica , Método Doble Ciego , Femenino , Tasa de Filtración Glomerular , Humanos , Enfermedades Renales/fisiopatología , Masculino , Persona de Mediana Edad , Fósforo/sangreRESUMEN
BACKGROUND: This is the first detailed pharmacokinetic report published on the administration of doxercalciferol [1alpha(OH)D(2)] recently introduced to treat secondary hyperparathyroidism. METHODS: 1alpha(OH)D(2) was administered in a range of single and multiple doses to volunteers with and without normal renal and/or hepatic function. Subsequent serial blood samples were assayed by HPLC/radioimmunoassay for the metabolite 1,25-dihydroxyvitamin D(2) [1,25(OH)(2)D(2)], the major active species. RESULTS: Bioavailability of 1,25(OH)(2)D(2) from a single 5 micro g 1alpha(OH)D(2) oral-capsule dose was estimated to be normally approximately 42% of that from a 5 micro g intravenous injection. Steady-state serum concentrations of 1,25(OH)(2)D(2) were attainable within 8 day, and fluctuated approximately 2.5-fold from peak to trough when oral 1alpha(OH)D(2) doses were taken every second day, and the terminal half-life was 34+/-14 h. Mean steady-state serum concentrations rose less than proportionally (from 20 to 45 pg/ml) on increasing oral 1alpha(OH)D(2) doses from 5 to 15 micro g every 48 h. Renal patients showed 39+/-37% increase in serum 1,25(OH)(2)D(2) concentration during 3-4 h haemodialysis sessions, but no other difference in steady-state pharmacokinetics was found between these or hepatically impaired patients and normal subjects. CONCLUSIONS: Given the sensitivity limits of current assays, the pharmacokinetics of this and other vitamin-D compounds is best elucidated from steady-state studies. The pharmacokinetics of 1,25(OH)(2)D(2) from 1alpha(OH)D(2) doses appears to be similar to that of 1,25(OH)(2)D(3) from 1alpha(OH)D(3) doses, albeit D(3) data have to date largely derived from single-dose studies. Deviation of 1,25(OH)(2)D(2) pharmacokinetics from linearity appears to be marginal enough to be clinically manageable with adequate precaution.
Asunto(s)
Ergocalciferoles/administración & dosificación , Ergocalciferoles/farmacocinética , Hiperparatiroidismo Secundario/tratamiento farmacológico , Glándulas Paratiroides/efectos de los fármacos , Vitamina D/análogos & derivados , Administración Oral , Adulto , Anciano , Disponibilidad Biológica , Estudios de Casos y Controles , Estudios Cruzados , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Estudios de Seguimiento , Humanos , Hiperparatiroidismo Secundario/diagnóstico , Infusiones Intravenosas , Fallo Renal Crónico/complicaciones , Hepatopatías/complicaciones , Masculino , Dosis Máxima Tolerada , Persona de Mediana Edad , Glándulas Paratiroides/metabolismo , Hormona Paratiroidea/metabolismo , Valores de Referencia , Factores de Riesgo , Resultado del TratamientoRESUMEN
In this study, we used molecules with either of the structural differences in the side chains of vitamin D(2) and vitamin D(3) to investigate which feature is responsible for the significant differences in their respective metabolism, pharmacokinetics and toxicity. We used two cell model systems-HepG2 and HPK1A-ras-to study hepatic and target cell metabolism, respectively. Studies with HepG2 revealed that the pattern of 24- and 26-hydroxylation of the side chain reported for 1alpha-hydroxyvitamin D(2) (1alpha-OH-D(2)) but not for 1alpha-OH-D(3) is also observed in both 1alpha-OH-D(4) and Delta(22)-1alpha-OH-D(3) metabolism. This suggests that the structural feature responsible for targeting the enzyme to the C24 or C26 site could be either the C24 methyl group or the 22-23 double bond. In HPK1A-ras cells, the pattern of metabolism observed for the 24-methylated derivative, 1alpha,25-(OH)(2)D(4), was the same pattern of multiple hydroxylations at C24, C26 and C28 seen for vitamin D(2) compounds without evidence of side chain cleavage observed for vitamin D(3) derivatives, suggesting that the C24 methyl group plays a major role in this difference in target cell metabolism of D(2) and D(3) compounds. Novel vitamin D(4) compounds were tested and found to be active in a variety of in vitro biological assays. We conclude that vitamin D(4) analogs and their metabolites offer valuable insights into vitamin D analog design, metabolic enzymes and maybe useful clinically.