2MD (DP001), a Single Agent in the Management of Hemodialysis Patients: A Randomized Trial.

BACKGROUND: Vitamin D analogs and calcimimetics are used to manage secondary hyperparathyroidism (SHPT) in dialysis patients. DP001 is an oral vitamin D analog that suppresses parathyroid hormone (PTH) in uremic rats, osteopenic women, and hemodialysis patients. The safety and effectiveness of DP001 suppressing PTH in dialysis patients previously managed with active vitamin D with or without a calcimimetic are presented. METHODS: A multicenter, randomized, double-blind study compared DP001 to placebo in hemodialysis patients with serum-intact PTH (iPTH) ≥300 pg/ml. The primary efficacy endpoint was the proportion of patients achieving 2 consecutive ≥30% decreases in iPTH levels during the 12 weeks of treatment. Calcium, phosphorus, calcium × phosphorus product and safety were also evaluated. The responses to DP001 were compared in patients previously treated with both active vitamin D and a calcimimetic to those previously on active vitamin D alone. RESULTS: Sixty-two patients were randomized (n = 34 DP001; n = 28 placebo). At week 12, 78% of all DP001-treated patients and 7% of all placebo-treated patients achieved the primary endpoint (p < 0.0001); iPTH fell 45% in the DP001 group and increased 37% in the placebo group. No patient exceeded the safety threshold of 2 consecutively corrected serum calcium levels ≥11.0 mg/dl. Patients previously on cinacalcet plus active vitamin D also responded to DP001 (n = 10) resulting in a 55% decrease in iPTH, while those on placebo (n = 9) increased by 70%. CONCLUSION: DP001 safely and effectively suppressed iPTH in hemodialysis patients with SHPT that were previously managed with active vitamin D alone or with a calcimimetic (www.clinicaltrials.gov, NCT01922843).

Novel, selective vitamin D analog suppresses parathyroid hormone in uremic animals and postmenopausal women.

BACKGROUND: The use of 1α-hydroxylated vitamin D therapy to control secondary hyperparathyroidism in renal failure patients has been a success story, culminating with the demonstration of increased life expectancy in patients treated with these compounds. However, hypercalcemic episodes have been a recurrent problem with these therapies and have resulted in the added use of calcium mimetics. Clearly there is good reason to search for improved vitamin D therapy. In our inventory of vitamin D compounds, 2-methylene-19-nor-(20S)-1α,25-dihydroxyvitamin D3 (2MD) surfaced as a potential candidate. This was based on its preferential localization in the parathyroid gland and a clear suppression of serum parathyroid hormone (PTH) levels without a change in serum calcium in a clinical trial in postmenopausal women. METHODS: 2MD has now been tested in the rat 5/6-nephrectomy model of renal failure, and in postmenopausal women to determine if it can suppress serum PTH at doses that do not elevate serum calcium and serum phosphorus concentrations. RESULTS: Daily oral treatment of uremic rats on 2.5 ng/bw/day of 2MD dramatically suppressed PTH without a change in serum calcium or serum phosphorus. Further, PTH was suppressed in postmenopausal women after only 3 daily oral doses of 2MD that continued for 4 weeks with no change in serum calcium or serum phosphorus. CONCLUSION: These results coupled with a pharmacokinetic half-life of ~24 h suggest that 2MD given either daily or at the time of dialysis may be a superior therapy for secondary hyperparathyroidism in chronic renal failure patients.

Telehealth with remote blood pressure monitoring for postpartum hypertension: A prospective single-cohort feasibility study.

OBJECTIVE: Investigate feasibility of telehealth with remote blood pressure monitoring for management of hypertension in postpartum women at risk of severe hypertension after hospital discharge. METHODS: In a single-center, prospective single-cohort feasibility study, women with hypertension in pregnancy participated in a postpartum telehealth intervention for blood pressure management after discharge. The primary feasibility outcome measures were recruitment and retention through 6 weeks postpartum. Secondary outcomes included the incidence of severe postpartum hypertension and/or need for blood pressure treatment after discharge, participant satisfaction, and 6-week hospital readmission. Participants received a tablet and equipment to transmit vital signs to a central monitoring site daily. Participants participated in telehealth or telephone visits with a nurse at 48 h and as needed. RESULTS: Among 1413 deliveries 263 (19%) women had hypertension in pregnancy and 55/124 (47%) of women approached were consented. The retention rate was 95%. Among study participants, the incidence of severe hypertension after discharge was 9 (16%). 29 (53%) of participants required treatment due to exacerbations in blood pressure after discharge, in which 9(16%) were severe. There were no hospital readmissions. Overall 39 (86%) participants were satisfied with the remote monitoring. CONCLUSIONS: Feasibility and participant satisfaction were demonstrated. The incidence of severe hypertension and need for blood pressure treatment after discharge and during 6 weeks postpartum was 16% and 53%. Our results indicate telehealth is a promising strategy for postpartum hypertension management to decrease maternal morbidity and hospital readmission.

Pharmacokinetics of a New Oral Vitamin D Receptor Activator (2-Methylene-19-Nor-(20S)-1α,25-Dihydroxyvitamin D3) in Patients with Chronic Kidney Disease and Secondary Hyperparathyroidism on Hemodialysis.

BACKGROUND: 2-Methylene-19-nor-(20S)-1α,25-dihydroxyvitamin D3 (DP001 or 2MD) is a novel, potent 1α-hydroxylated vitamin D analog that binds to the vitamin D receptor and suppresses parathyroid hormone synthesis and secretion with potential for an improved safety profile compared to existing active vitamin D analogs. The purpose of this study was to evaluate the pharmacokinetics of DP001 given orally after hemodialysis. METHODS: DP001 (550 ng) was given orally to 11 hemodialysis patients with secondary hyperparathyroidism after each dialysis session (3 times/week) for 4 weeks. Pharmacokinetic analyses were performed after the first and final dose. RESULTS: After the first and final dose, the half-life of DP001 was similar (55.8 ± 13.0 and 50.8 ± 8.2 h, respectively). At 4 weeks, the time to maximum plasma concentration was 4.0 ± 0.8 h, with a concentration maximum of 3.4 ± 0.3 pg/mL. The area under the curve (0 to infinity) after the final dose was 204.3 ± 23.9 pg h/mL, and apparent volume of distribution was 2.03 ± 0.22 L/kg. At week 4, mean intact parathyroid hormone was suppressed 33% from the baseline (pre-dose) value (313 ± 52 vs 462 ± 39 pg/mL, respectively). No clinically significant changes from baseline values were found for vital signs, electrocardiogram measurements, or other laboratory parameters, including serum calcium and phosphorus. CONCLUSIONS: In hemodialysis patients, DP001 has a longer half-life than existing vitamin D therapies and enables control of parathyroid hormone when administered every 2-3 days on the day of dialysis. It is effective at a lower concentration maximum and area under the curve than other clinically available vitamin D compounds. DP001 may represent a therapeutic improvement over existing compounds due to rapid and extensive distribution to its target and its long half-life enabling sustained parathyroid hormone suppression. These studies support further evaluation of DP001 in longer-term treatment of secondary hyperparathyroidism.

Diaminobutane (DAB) dendrimers are potent binders of oral phosphate.

Reduction of blood phosphorus is a critical component in the management of secondary hyperparathyroidism in chronic kidney disease patients. In addition to dialysis treatment and dietary phosphorus restriction, oral phosphate binders are often consumed with meals to reduce the availability of food phosphorus. Several oral phosphate binders are approved for use in chronic kidney disease patients, but all have practical limitations because of toxicity, poor efficacy, or high cost. Using an in vivo method to measure intestinal phosphate absorption in rats using radiolabeled phosphate, we found that first-, second-, third-, and fifth-generation diaminobutane dendrimer compounds, DAB-4-Cl, DAB-8-Cl, DAB-16-Cl, and DAB-64-Cl, respectively, drastically reduce the absorption of inorganic phosphate in a dose-dependent manner. To avoid complications of metabolic acidosis caused by hydrochloride salts, an acetate salt, DAB-9-AcOH, was prepared and shown to be equally effective at binding radiolabeled phosphate as DAB-8-Cl. DAB-8-AcOH was further shown to increase fecal phosphorus and decrease serum phosphorus in a dose-dependent manner when fed to rats. These data suggest that dendrimer compounds are of great potential use in the binding of food phosphate for the management of hyperparathyroidism secondary to chronic kidney disease.

Vitamin D and autoimmune diabetes.

The biologically active form of vitamin D, 1,25(OH)(2)D(3), is a potent modulator of the immune system as well as a regulator of bone and mineral metabolism. Vitamin D-deficiency in infancy and vitamin D receptor gene polymorphisms may be risk factors for insulin-dependent Diabetes mellitus (IDDM). 1,25(OH)(2)D(3) and its analogs significantly repress the development of insulitis and diabetes in the non-obese diabetic (NOD) mouse, a model of human IDDM. 1,25(OH)(2)D(3) may modulate IDDM disease pathogenesis by repression of type I cytokines, inhibition of dendritic cell maturation, and upregulation of regulatory T cells. The function of vitamin D as a genetic and environmental determining factor for IDDM, the protective role of 1,25(OH)(2)D(3) and its analogs in a mouse model of IDDM, and the possible mechanisms by which this protection occurs will be reviewed.

Oral administration of 1,25-dihydroxyvitamin D3 completely protects NOD mice from insulin-dependent diabetes mellitus.

1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), the biologically active form of vitamin D, is widely recognized as a modulator of the immune system as well as a regulator of mineral metabolism. The objective of this study was to determine the effects of vitamin D status and treatment with 1,25(OH)(2)D(3) on diabetes onset in non-obese diabetic (NOD) mice, a murine model of human type I diabetes. We have found that vitamin D-deficiency increases the incidence of diabetes in female mice from 46% (n=13) to 88% (n=8) and from 0% (n=10) to 44% (n=9) in male mice as of 200 days of age when compared to vitamin D-sufficient animals. Addition of 50 ng of 1,25(OH)(2)D(3)/day to the diet prevented disease onset as of 200 days and caused a significant rise in serum calcium levels, regardless of gender or vitamin D status. Our results indicate that vitamin D status is a determining factor of disease susceptibility and oral administration of 1,25(OH)(2)D(3) prevents diabetes onset in NOD mice through 200 days of age.

Regulation of the murine renal vitamin D receptor by 1,25-dihydroxyvitamin D3 and calcium.

Renal vitamin D receptor (VDR) is required for 1,25-dihydroxyvitamin D3-[1,25(OH)2D3]-induced renal reabsorption of calcium and for 1,25(OH)2D3-induced 1,25(OH)2D3 24-hydroxylase. The long-term effect of vitamin D and dietary calcium on the expression of renal VDR was examined in the nonobese diabetic mouse. Vitamin D-deficient and vitamin D-replete mice were maintained on diets containing 0.02%, 0.25%, 0.47%, and 1.20% calcium with or without 50 ng of 1,25(OH)2D3 per day. Vitamin D-replete mice on a 1.20% calcium diet had renal VDR levels of 165 fmol/mg protein. Calcium restriction caused renal VDR levels to decrease to <30 fmol/mg protein in vitamin D-deficient mice and to approximately 80 fmol/mg protein in vitamin D-replete mice. When dietary calcium was present, 50 ng of 1,25(OH)2D3 elevated the VDR levels 2- to 10-fold, depending on vitamin D status and the level of calcium. In the absence of either vitamin D or calcium, the VDR mRNA was expressed at a basal level. 1,25(OH)2D3 supplementation caused relative VDR mRNA to increase 8- to 10-fold in the vitamin D-deficient mouse when dietary calcium was available. This increase was completely absent in the calcium-restricted mice. This in vivo study demonstrates that 1,25(OH)2D3 and calcium are both required for renal VDR mRNA expression above a basal level, furthering our understanding of the complex regulation of renal VDR by 1,25(OH)2D3 and calcium.