MXPA98000342A - Use of 19-nor-vitamin d compounds for the prevention of hyperphosphatemia in patients with ri disorder - Google Patents

Abstract

The present invention relates to the 19-nor-vitamin D analogs and particularly 19-nor-1alpha, 25-dihydroxyvitamin D2, possess low calcemic and phosphotemic activity, while also having the ability to suppress production of parathyroid hormone (PTH) . The suppressive effect on PTH secretion of these 19-nor analogues without significant changes in serum calcium and serum phosphorus make them ideal tools for the treatment of secondary hyperparathyroidism in patients with kidney disorders.

Description

USE OF 19-NOR-VITAMIN D COMPOUNDS FOR THE PREVENTION OF HYPERPHOSPHATEMIA IN PATIENTS WITH KIDNEY DISORDER Background of the Invention Vitamin D is essential for life in higher animals. It is one of important regulators of calcium and phosphorus and is required for proper development and maintenance of bones. However, during the last of each, the spectrum of activities promoted by l, 25- (OH) 2D3 has been found to extend beyond a role in calcium homeostasis. In addition to its action on intestine, bone, kidney and thyroid glands to control calcium in serum, this hormone has been found to have important cell differentiation activity. Receptors for this hormone have been identified in dozens of different target cells that respond to 1,25- (OH) 2D3, with a diverse range of biological action. These recently discovered activities have suggested other therapeutic applications of l, 25- (OH) 2D3 including hyperparathyroidism, psoriasis, cancer and immune regulation. Secondary hyperparathyroidism is a universal complication in patients with chronic renal failure. Due to the ability to suppress parathyroid hormone (PTH), l, 25- (OH) 2D3 has been used successfully in the treatment of secondary hyperparathyroidism, Slapolsky et al. "Market Suppression of Secondary Hyperparathyroidism by Intravenous Administration of 1,25-dihydroxycholecalciferol in Uremic patients", (Suppression, Secondary Hyperparathyroidism Marked by Intravenous Administration of 1,25-dihydroxycholecalciferol in Uremic Patients 1984. Clin. Invest. 74: 2136-2143 , 1984. Its use is often avoided, however, by the development of hypercalcemia resulting from its potent action on intestinal absorption and bone mineral mobilization.Hyperphosphatemia is also a persistent problem in patients with chronic hemodialysis and can also be aggravated by dose Therapeutics of 1, 25- (OH) 2D3 Delmez et al. "Hyperphosphatemia: Its Consequences and Treatment in Patients with Chronic Renal Disease", (Hyperphosphemy: Its consequences and treatment in patients with chronic kidney disease) Am. J. KidneyDis. : 303-317, 1992; Quarles et al. "Prospective Trial of Pulse Oral versus Intravenous Calcitriol Treatment of Hyp erparathyroidism in ESRD "(Test of oral pulse against intravenous calcitriol treatment of hyperparathyroidism in ESRD), Kidney Int. 45: 1710-1721, 1994. In addition, the control of phosphate absorption with large doses of calcium carbonate, Meyrier and collaborators "The Influence of a High Calcium Carbonate Intake on Bone Disease in Patients Undergoing Hemodialysis" (The influence of high absorption of calcium carbonate in bone disease in patients undergoing hemodialysis), Kidney Int. 4: 146-153, 1973; Moriniere et al. "Substitution of Aluminum Hydroxide by High Doses of Calcium Carbonate in Patients on Chronic hemodialysis: Disappearance of Hyperaluminaemia and Equal Control of Hyperthyroidism "(Substitution of aluminum hydroxide by high doses of calcium carbonate in chronic hemodialysis patients: disappearance of hyperaluminaemia and equal control of hyperparathyroidism, Proc. Eur. Dial Transplant Assoc. 19: 784-787 , 1983; Slatopolsky et al., "Calcium carbonate as a Phosphate Binder in Patients with Chronic Renal failure Undergoing Dialysis" (Calcium carbonate as a phosphate binder in patients with chronic renal failure who undergo dialysis, New Engl. 315: 157-161, 1986, only increases the risk of hypercalcemia by 1, 25- (OH) 2D3 therapy.Thus, an analogue of l, 25- (OH) 2D3 that can suppress PTH with minor effects on Phosphate and calcium metabolism would be an ideal tool for the control of secondary hyperparathyroidism Compendium of the Invention A method to avoid hyperphosphatemia in a patient who has a kidney disorder. then administer to the patient a vitamin D compound that suppresses PTH and minimizes the absorption of intestinal phosphorus. Preferably, the vitamin D compound is a 19-ñor vitamin D compound and more preferably is 19-nor-la, 25-dihydroxyvitamin D2.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates the effects of l, 25- (OH) 2D3 and 19-nor-1, 25- (OH) 2D2 on PTH secretion in primary culture of bovine parathyroid cells. Figure 2 illustrates the comparative effects of 1,25- (OH) 2D3 and 19-nor-l, 25- (OH) 2D2 on serum calcium in uremic rats. Figure 3 illustrates the comparative effects of 1,25- (OH) 2D3 and 19-nor-l, 25- (OH) 2D2 on ionized calcium in uraemic rats. Figure 4 illustrates the comparative effects of 1,25- (OH) 2D3 and 19-nor-l, 25- (OH) 2D2 in serum phosphorus. Figure 5 illustrates the comparative effects of 1,25- (OH) 2D3 on pre-pro PTH mRNA. Figure 6 illustrates the effects of 19-nor-l, 25- (OH) 2D2 on pre-pro PTH mRNA. Figure 7 illustrates the effects of l, 25- (OH) 2D3 on serum PTH. Figure 8 illustrates the effects of 19-nor-l, 25- (OH) 2D2 on serum PTH. Description of the Invention Compounds useful in the present invention are those vitamin D compounds that can suppress PTH while at the same time having minimal or no effects on phosphate and calcium metabolism. One class of vitamin D compounds that meets these criteria are the 19-nor-analogs, ie compounds wherein the ring-exocyclic methylene group A (carbon 19) typical of the entire vitamin D system, has been removed and replaced by two hydrogen atoms. Structurally, these novel analogs are characterized by the general formula I illustrated below: wherein X1 and X2 each independently represent hydrogen or a protective hydroxy group. The group of secondary chain R in the structure previously illustrated I, can represent any of the types of steroid side chains currently known. More specifically, R may represent a saturated or unsaturated hydrocarbon group with 1 to 35 carbon atoms, which may be straight chain, branched or cyclic and may contain one or more additional substituents such as protected hydroxy or hydroxy groups, fluorine, carbonyl, ester, epoxy, amino or other heteroatom groups. Preferred secondary chains of this type are represented by the structure below: wherein the stereochemical center (corresponding to C-20 in the steroid numbering) can have the R or S configuration, (ie, the natural configuration, with respect to the configuration carbon 20 or 20-epi) and where Z is choose from Y, -OY, -CH2OY, -C = CY and -CH = CHY, where the double bond can have the cis or trans geometry. and where Y is chosen from hydrogen, methyl, -CR50 and a group of the structure R 'R2 R3 - (CH2) m- C- (CH2) n-C-R5 XR4 wherein m and n, independently represent integers from 0 to 5, wherein R 1 is selected from hydrogen, hydroxy, protected hydroxy, fluorine, trifluoromethyl and C 1 -C 5 alkyl, which may be straight or branched chain and optionally contain any protected hydroxy or hydroxy substituent and wherein each of R 2, R 3 and R 4, independently is selected from hydrogen, fluorine, trifluoromethyl and alkyl of 1 to 5 carbon atoms which may be straight or branched chain and optionally contain a hydroxy or hydroxy substituent protected and wherein R1 and R2 together represent an oxo group, or an alkylidene group = CR2R3, or the group - (CH2) wherein p is an integer from 2 to 5, and wherein R3 and R4 together represent an oxo group, or the group - (CH2) q wherein q is an integer from 2 to 5, wherein R5 represents hydrogen, hydroxy, protected hydroxy or alkyl with 1 to 5 carbon atoms and wherein any of the groups at positions 20, 22 and 23 respectively in the chain l Ateral can be replaced by an oxygen atom. As used in the description, and in the claims, the term "hydroxy protecting group" refers to any group commonly employed for the protection of hydroxy functions during subsequent reactions, including for example acyl or alkylsilyl groups such as trimethyl silyl, triethylsilyl, t-butyldimethylsilyl and analogous alkyl or arylsilyl group, or alkoxyalkyl groups such as methoxymethyl, ethoxymethyl, methoxyethoxymethyl, tetrahydrofuranyl or tetrahydropyranyl. A "protected hydroxy" is a hydroxy function derived by one of the above protective hydroxy groups. "Alkyl" represents a straight or branched chain hydrocarbon group with 1 to 10 carbon atoms in all its isomeric forms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, etc., and the terms "hydroxyalkyl" , "fluoroalkyl" and "deuteroalkyl" refer to this alkyl group substituted by one or more hydroxy, fluoro or deuterium groups, respectively. An "acyl" group is an alkanoyl group with 1 or 6 carbon atoms in all its isomeric forms, or an aroyl group such as benzoyl, or benzoyl groups substituted with halo, nitro or alkyl, or alkoxycarbonyl group of the type Alkyl-0- CO, such as methoxycarbonyl, ethoxycarbonyl, propyloxycarbonyl, etc., or an acyl dicarboxylic group such as oxalyl, malonyl, succionoyl, glutaroyl, or adipoyl. The term "aryl" means a phenyl group or group or an alkyl, phenyl group substituted with nitro or halo. The term "alkoxy" means the alkyl-0- group. Important specific examples of secondary chains are the structures represented by formulas (a), (b), (c), (d), and (e) below, that is, the secondary chain as it occurs in 25-hydroxyvitamin D3 (to); vitamin D3 (b); 25-hydroxyvitamin D2 (c); vitamin D2 (d); and the C-24-epimer of 25-hydroxyvitamin D2 (e).

More specifically, a preferred compound for use in the present invention is 19-nor-loi, 25-dihydroxyvitamin D2, ie, formula I wherein X1 and X2 are both hydrogen together with the side chain (c) illustrated above. A method of synthesizing 19-or-vitamin D compounds has been reported by Perlam et al., Tetrahedron Letters 13, 1823 (1990). This method involves the removal of the C-19-methylene group in existing vitamin D compound, and US Patents are also described. No. 5,237,110 and 5,246,925. Another method involves a convergent synthesis of 19-nor-vitamin D compounds and is described in U.S. Pat. No. 5,281,731. Still another method involves the condensation of a bicyclic acetone with a phosphine oxide derivative and is described in U.S. Pat. No. 5,086,191.

For treatment purposes, the active compounds of this invention can be formulated as solutions in harmless solvents, or as emulsions, suspensions or dispersions in convenient innocuous solvents or carriers or as pills, tablets or capsules containing solid carriers according to conventional methods known in the art. the specialty. For topical applications, the compounds are advantageously formulated as creams or ointments or similar vehicle suitable for topical applications. Any such formulation may also contain other pharmaceutically acceptable and non-toxic excipients such as stabilizers, antioxidants, binders, coloring agents or emulsifying agents or flavor modifiers. The compounds are advantageously administered by injection, or by intravenous infusion of suitable sterile solutions, or in the form of oral doses via the alimentary canal or topically in the form of suitable ointments, lotions, or transdermal patches. In the treatment of hyperparathyroidism, the compounds are administered in doses sufficient to suppress parathyroid activity, such as to achieve parathyroid hormone levels, in the normal range. Suitable amounts of doses are 1 to 500 μg of compound per day, these doses are adjusted, depending on the diseases to be treated, their severity and the response or condition of the subject, or well understood in the specialty.

The invention is described more specifically by the following illustrated examples. Materials and Methods PTH secretion in culture or bovine parathyroid cells Primary monolayer culture cells of bovine parathyroid cells were prepared according to the method of MacGregor et al with minor modifications. MacGregor and collaborators in "Primary Monolayer Cell Culture of Bovine Parathyroids: Effects of Calcium Isoproterenol and Growth Factors" (Primary bovine paratoroid monolayer cell culture: effects of calcium isoproterenol and growth factors), Endocrinology 30: 313-328, 1983. Briefly, bovine parathyroid glands were cut from foreign tissue, sliced to approximately 0.5 mm in thickness with a Stadie-Riggs tissue slicer (Thomas Scientific, Swedesboro, NJ) and placed in culture medium DME (HG) / Ham's F -12 that contains (50/50) of collagenase 2.5 mg / ml (Boehringer Mannheim, Indianapolis, IN) and 0.5 mM of total calcium. The suspension (1 g of tissue per 10 ml of medium) is stirred in a water bath at 37 ° C for 90 minutes, and is periodically aspirated through a large drilled hole that is made in an Eppendorf pipette tip connected to the a syringe of 60 ml. The digested tissue is filtered through gauze, resuspended and washed 3 times with culture medium containing DME medium (HG) / Ham's F12 (50/50), 1 mM total calcium, 4% neonatal bovine serum, 15 mM Hepes, 100 IU / ml penicillin, 100 μg / ml streptomycin, 5 μg / ml insulin, 2 mM glutamine and 1% non-essential amino acids. Cells were coated at 80,000 cell / cm 2. After 24 hours, the medium was replaced with the same medium as described above, except that the serum was replaced with 1 mg / ml of bovine serum albumin and 5 μg / ml of holotransferin. This medium was replenished every 24 to 48 hours. PTH Secretion Studies The test media containing various concentrations of l, 25- (OH) 2D3 or 19-nor-l, 25- (OH) 2D2 were prepared by adding the indicated ethanol solutions of compounds to the media.; final ethanol concentration was 0.1%. After incubation, medium was collected, centrifuged and then stored at -20 ° C until analyzed by PTH. PTH was assayed using the CH9 anti body, which recognizes intact middle and terminal carboxy fragments of PTH. Details of the antisera recognition characteristics and radio immunoassay methodology (RIA) have been previously described in Hruska et al. ("Metabolism of Immunoreactive Parathyroid Hormone in the Dog, The Role of the Kidney and the Effects of Kidney Chronic Desease" (Metabolism of immunoreactive parathyroid hormone in the dog, kidney paper and the effects of chronic kidney disease), Clin Invest. 56: 39-48, 1975. Cell protein in each sample is determined by sonicating the cells in 1 mM NaOH. and assaying an aliquot using a protein assay kit (Bio-rad Laboratories, Richmond, CA) All PTH values were corrected for cellular protein Reverse Transcriptase Polymerase Chain-Reverse Transcriptase (RT-PCR) The pair of parathyroid glands from a single animal was homogenized in 250 μl of ARNzol (Cinna Biotech, Houston, TX), mixed with 25 μl of chloroform, vortexed and centrifuged in a microfuge for sep Plowing phases The upper aqueous phase (125 μl) was mixed with 20 μl of 1 mg / ml glycogen, 145 μl of 2-propanol and placed at -20 ° C overnight. Total co-precipitated RNA and glycogen were pooled by centrifugation (microfuge) and washed twice with 70% ethanol. dT primed cDNA Oligo was prepared from 40% of the total RNA with the help of a computer obtained from Promega (Madison, Wl). One sixth of each cDNA preparation was amplified by PCR using 5 'sense oligonucleotide primers (ATG TCT GCA AGC ACC ATG GCT AAG) 3', which represent amino acids -30 to -23 and 5 'antisense (CTG AGA TTT AGC CTT AAC TAA TAC) 3 'representing amino acids 77 to 84 of pre-pro PTH mRNA from rats. The PCR conditions were 94 C x 1 minute denaturation, annealing 60 C x 1 minute and extension 72 C x 2 minutes, for 18 cycles. Amplification of 0-actin mRNA from cDNA was achieved using the same conditions with 5 'sense primer (GAT ATC GCC GCG CTC GTC GAC) 3' and 5 'antisense (AGC CAG GTC CAG ACG CAG GAT GGC ATG) 3 'with a total of 26 cycles. PCR products were separated by 1.2% agarose gels in TAE buffer containing ethidium bromide. The gels were photographed in an ultraviolet light box with Polaroid film type 665 to give a negative. The Polaroid negative of each gel was scanned (Omni Media 6cx / csx, X-ray Scanner Corporation, Torrance, CA) and analyzed using Sepra Sean 2001 software (Integrated Separation Systems, Natwick, MA). The amount of pre-pro PTH and mRAN jS-actin from up to 32 different animals could be processed simultaneously to eliminate potential inter-assay variation. The plasmid sequencing (pCRII, Invitrogen) containing the PCR products established its identity as pre-pro rat PTH and rat 0-actin. Calcaemic response to 1,25- (0H) 2D3 and 19-nor-l.25- (OH) 2O2 Kidney failure was induced in a group of 150 female Sprague-Dawley rats by 5/6 nephrectomy. The procedure involves ligating most branches of the left renal artery and right nephectromy. The rats were fed a diet containing 0.6% calcium and 0.7% phosphorus for a period of 8 weeks. At the end of this period, all the rats weighed approximately the same amount (260 to 280 gm). To determine the response of l, 25- (OH) 2D3 or 19-nor-l, 25- (OH) 2D2 in calcium in serum, uraemic rats were injected intraperitially (IP) on a daily basis for a period of 10 days with vehicle (propylene glycol μl) 1,25- (0H) 2D3, or 19-nor-l, 25- (OH) 2D2 (10,100 or 1,000 ng / rats). To determine the response of the parathyroid glands to l, 25- (OH) 2D3 or 19-ñor-1, 25- (OH) 2D2, rats with chronic renal failure were divided into three main groups: 1) vehicle; 2) l, 25- (OH) 2D3 (2.0, 4.0, or 8.0 ng / rat) and 3) 19-nor-1, 25- (OH) 2D2 (8.0, 25 or 75 ng / rat) administered IP each day sauteed for a period of 8 days. In addition, studies were conducted on normal animals. Analytical Determinations Total calcium was determined by atomic absorption spectrophotometry (Perkin Elmer, Model 1100B, Norwalk, CT), and ICa by a specific ionized calcium electrode (model ICA-1, Radiometer, Copenhagen). Plasma creatinine and phosphorus were determined by the autoanalyzer (COBAS MIRA Plus, Branchburg, NJ). Intact PTH was measured by IRMA specific for intact rat PTH from the Nichols Institute (San Capistrano, CA). The diet was purchased from DYETS, Inc. (Bethlehem, PA). l, 25- (OH) 2D3 was provided by Dr. Milan Uskokovic (Hoffman La Roche Laboratories, Nutley, New Jersey, USA), and 19-nor-l, 25- (OH) 2D2 was provided by Abbott Laboratories, Abbott Park, Illinois, USA. Statistical Analysis All data are expressed as mean ± SEM. A one-way analysis of variance (ANOVA) was used for comparisons between the groups.

Results Formula 1 wherein X1 and X2 are both hydrogen and R is side chain (c) illustrates the chemical structure of 19-nor-1, 25- (OH) 2D2. This analog has carbon 28 and the double bond in carbon 22 that are characteristic of vitamin D2 compounds, but lacks the carbon 19 and the exocyclic double bond that is found in all the natural vitamin D metabolites. The effect of l, 25- (OH) 2D3 and 19-nor-l, 25- (OH) 2D2 on secretion of PTH in primary culture of bovine thyroid cells is described in Figure 1. All groups had measured PTH secretion at the same time the final day in cultivation (72 hours). Both compounds have a significant dose-dependent suppressive effect on PTH secretion (p <0.001). The maximum suppressive effect is obtained with both compounds at a concentration of 10"7 M. There was no significant difference in the suppressive effect on PTH secretion in vitro between the two compounds.L comparative effects of l, 25- (OH) 2D3 and 19 -orig-1,25- (OH) 2D2 in total serum calcium are illustrated in Figure 2. Rats were injected IP on a daily basis for a period of 10 days with vehicle (propylene glycol 100 μg / ml) 1, 25- (OH) 2D3, 10 ng / rat) or 19-nor-l, 25- (OH) 2D2 (10, 100 or 1,000 ng / rat) Daily injections (IP) of 19-nor-l, 25- (OH) 2D2 10 ng / rat did not significantly increase serum calcium When the dose of 19-nor-l, 25- (OH) 2D2 was increased to 100 ng / rat, the calcium increase in serum was same as that induced by l, 25- (OH) 2D3 at 10 ng / rat.All the biochemical parameters measured at sacrifice time (two months of renal failure) are illustrated in Table 1 and Figures 3 and 4. Creatinine serum increased from 0.64 ± 0.02 in normal rats at 1.15 ± 0.05 mg / dl in uraemic animals (p < 0.001). Ni l, 25- (OH) 2D3 or 19-nor-l, 25- (OH) 2D2 modified the serum creatinine in uremic animals. As illustrated in Figure 3, serum ionized calcium was increased in uraemic rats receiving 8 ng 1,25- (OH) 2D3 each day sautéed for eight days (5.08 ± .06 vs. 4.81 ± .08 mg / dl ) in uraemic control animals p < 0.002). 19-nor- 1, 25- (OH) 2D2. Ionized calcium from serum did not increase even at the largest dose (75 ng / rat x four times). As illustrated in Figure 4, 1,25- (0H) 2D3 (dose of 8 ng) increased serum phosphorus from 5.57 + -.5 (uraemic control) to 8.64 ± 1.15 mg / dL (p <0.01). ). None of the doses of 19-nor-l, 25- (OH) 2D2 increased serum phosphorus (Table 1 Figure 4). Parathyroid hormone in normal rats was 40 ± 8.6 pg / ml and increased to 243 ± 83 pg / ml in uraemic rats. The only dose of l, 25- (OH) 2D3 that produces a statistically significant decrease (p <0.01) in PTH levels was the dose of 8 ng. PTH decreased from 202 ± 31 to 90 ± 20 pg / ml. (However, ICa increased from 4.81 ± 0.08 to 5.08 ± 0.06 mg / dl (p <0.02) (Figure 5).) All doses of 19-nor-l, 25- (OH) 2D2 (8, 25, 75) produce a significant decrease in circulating PTH levels. The greatest effect was observed with the dose of 75 ng.

PTH decreased from 225 ± 60 to 53 ± 16 pg / ml (Figure 6) (7.5 decrement); however, none of the doses of 19-nor-l, 25- (0H) 2D2 increased the ionized calcium. The results of reverse transcriptase (PCR in mRAN pre-pro PTH, are illustrated in Figures 7 and 8. l, 25- (OH) 2D3 suppressed mRAN pre-pro PTH in a dose-dependent manner (Figure 7). Similar results with 19-nor-l, 25- (0H) 2D2 (Figure 8) Discussion Chronic renal failure is characterized by changes in mineral homeostasis, with secondary hyperparathyroidism occurring even in the early stages of renal failure, which leads The development of renal osteodystrophy, both low levels of 1,25- (0H) 2D3 and phosphate retention, are responsible for the development of secondary hyperparathyroidism, although serum phosphorus is usually normal in patients with early renal failure., phosphate restriction can reduce secondary hyperparathyroidism. Restriction of phosphate in the diet increases the levels of 1, 25- (OH) 2D3, Pórtale and collaborators. "Effect of Dietary Phosphorus on Circulating Concentrations of 1, 25-dihydroxyvitamin D and Immunoreactive Parathyroid Hormone in Children with Modérate Renal Insufficiency" (Effect of phosphorus on diet in circulating concentrations of 1,25-dihydroxyvitamin D and immunoreactive parathyroid hormone in children with moderate renal insufficiency), J. Clin. Invest. 73: 1550-1589, 1984, which in turn decreases PTH by suppressing transcription of the PTH gene directly and by increasing intestinal calcium absorption. In later stages of renal failure, the extension of hyperparathyroidism and deficiency 1, 25- (OH) 2D3, and phosphate restriction have little effect at levels of 1, 25- (OH) 2D3, López-Hilker et al. "Phosphorus Restriction Reverses Hyperparatyroidism in Uremia Independent of Changes in Calcium and Calcitriol "(Restriction of phosphorus reverses hyperparathyroidism in uremia independent of changes in calcium and calcitriol), Am. J. Physiol. 259: F432-F437. 1990, presumably due to the decreased renal mass available for synthesis of 1, 25- (OH) 2D3. Several vitamin D analogs with low calcemic activity have been found almost as effective as l, 25- (OH) 2D3 in suppressing PTH secretion by cultured bovine parathyroid cells. This includes 22-oxacalcitriol (OCT) Brown and collaborators "The Non-Calcemic Analog of Vitamin D, 22-oxacalcitriol (OCT) Suppresses Parathyroid Hormone Synthesis and secretion" (The non-calcemic analogue of Vitamin D, 22-oxacalcitriol (OCT) suppresses synthesis and secretion of parathyroid hormone), J. Clin. Invest. 84: 728-732. 1989, as well as 1,25- (OH) 2-16-ene-23-ene-D3, 1,25- (OH) 2-24-dihimono-D3 and 1,25- (OH) 2-24-trihomo -22-ene-D3 and (unpublished data). To date, only 22-oxacalcitriol has been examined in detail for this action in vivo. Brown et al. "Selective Vitamin D Analogs and their Theraputic Applications" (Selective vitamin D analogs and their therapeutic applications), Sem. Nephrol 14: 156-174, 1994, reported that 22-oxacalcitriol despite its rapid release in vivo, can suppress mRNA PTH. Sub-maximal, low doses of calcitriol and OCT produce comparable inhibition. OCT has also been shown to suppress serum PTH in rats and uraemic dogs. In the current study, we used an analogue of l, 25- (OH) 2D3 with low calcemic and phosphataemic action, 19-nor-l, 25- (OH) 2D2. This calcitriol analog has carbon 28 and the double bond in carbon 22 that are characteristic of vitamin D2 compounds, but lacks the carbon 19 and the exocyclic double bond found in all natural vitamin D compounds. First, we organized in vitro studies, using a primary culture of bovine parathyroid cells. 19-nor-l, 25- (OH) 2D2 had a similar suppressive effect on PTH as 1.25- (OH) 2D3. A suppression of 52% in PTH release was obtained with 19-nor-l, 25- (OH) 2D2. There was no significant difference in the suppressive effect of PTH secretion between the two compounds. Subsequently, preliminary in vivo studies were performed to determine the calcemic activity of 19-nor-l, 25- (OH) 2D2. It was found that 1,25- (OH) 2D3 (10 ng / rat / 10 days) increases serum calcium in the same magnitude as 19-nor-l, 25- (OH) 2D2 (100 ng / rat / 10 days ). Because of this, three different doses of l, 25- (OH) 2D3 (2, 4, and 8 ng) and 19-nor-l, 25- (OH) 2D2 (8, 25, and 75 ng) were chosen for the chronic studies. After two months of renal failure, the animals received the two previous compounds at the three indicated doses, four times during a period of 8 days. As expected, 25- (OH) 2D3 suppressed PTH secretion and pre-pro PTH mRNA. However, this decrease was statistically significant only with the dose of 8 ng. This dose induces hypercalcemia and hyperphosphatemia. On the other hand, none of the doses of 19-nor-l, 25- (OH) 2D2 produce statistically significant changes in serum phosphorus or ionized calcium in serum. However, all doses of 19-nor-l, 25- (OH) 2D2 were effective in suppressing both PTH secretion and pre-pro PTH mRNA. Since a radioactive form of 19-ñor-1, 25- (OH) 2D2 was not available during these studies, we were unable to determine protein binding and half-life of the analogue. However, previous studies by DeLuca indicate that 19-nor-l, 25- (0H) 2D2 binds about 1/3 as well as l, 25- (OH) 2D3 to the porcine intestinal vitamin D receptor when compared to 1.25 - (OH) 2D3 (unpublished results). From the clinical point of view, one of the most difficult biochemical changes to correct in hemodialysis patients is hyperphosphatemia. Dialysis patients usually ingest approximately 1.0 to approximately 1.4 grams of phosphorus per day. Since the maximum amount of phosphorus that is removed during each dialysis is close to 800 to 100 mg, Hou et al. "Calcium and Phosphorus Fluxes During Hemodialysis with Low Calcium Dialysate" (Calcium and Phosphorus Flows During Hemodialysis with Low Calcium Dialysate) , Am. J. Kidney Dis. 18: 217-224. 1991, the remaining 2.5 to 3.5 grams of phosphorus ingested per week must be removed by other means. Thus, the use of phosphate binders such as calcium carbonate and calcium acetate is usually to correct hyperphosphatemia, Emmet et al. "Calcium Acétate Control of Serum Phosphorus in Hemodialysis Patients" (Calcium acetate control of serum phosphorus) in hemodialysis patients), Am. J. Kidney Dis. 27: 544-550, 1991; Shaefer et al. "The Treatment of Uraemic Hyperphosphataemia with Calcium Acétate and Calcium carbonate: A Comparative Study" (The treatment of uremic hyperphosphatemia with calcium acetate and calcium carbonate: a comparative study), Nephrol Dial Transplant 6: 170-175, 1991; Delmez et al. "Calcium Acétate as a Phosphorus Binder in Hemodialysis patients" (Calcium acetate as a phosphorus binder in hemodialysis patients), J. Am. Soc Nephrol 3: 96-102, 1992. Unfortunately l, 25- (OH ) 2D3 not only increases calcium absorption but also phosphorus making hyperphosphatemia more difficult to treat. In this way, hyperphosphatemia induced in part by the action of 1,25- (0H) 2D3 requires a further addition of calcium carbonate or calcium acetate, which can greatly increase serum ionized calcium levels. The product of high calcium-phosphate content that the patient can develop, imposes a tremendous risk for the development of metastatic calcifications, Arora et al. "Calcific cardiomypathy in Advanced Renal failure" (cardiomeopathy calcifies in advanced renal failure), Arch. Intern. Med. 1335: 603-605 1975; Rostand et al. "Myocardial Calcification and Cardiac Dysfunction in Chronic Renal Failure" (Myocardial Calcification and Cardiac Dysfunction in Chronic Renal Failure), Am. J. Med. 85: 651-657, 1988; Gipstein et al. "Calciphyalisis in Man A Syndrome of Tissue Necrosis and Vascular Calcifications in 11 Patients with Chronic Renal Failure" (Calcifiálisis in humans, a syndrome of tissue necrosis and vascular calcifications in 11 patients with chronic renal failure), Arch. Intern. Med. 136: 1273-1280, 176; Milliner et al. "Soft Tissue Calcification in Pediatric Patients with End-Stage Renal Disease" (Soft tissue calcification in pediatric patients with end-stage renal disease), Kidney Int. 38: 931-936, 1990. Therefore, the treatment it demands a decrease in the amount of l, 25- (OH) 2D3 administered to the patient, thereby decreasing the effectiveness of 1,25- (OH) 2D3 therapy to control PTH secretion.

The development of an analog of l, 25- (OH) 2D3 with minimal effect on calcium and phosphorus, such as 19-nor-l, 25- (OH) 2D2 is an ideal tool for the treatment of hyperparathyroidism and renal osteodystrophy. This analogue (19-nor-l, 25- (OH) 2D2) has been shown to be as effective as l, 25- (OH) 2D3 in suppressing PTH in vitro and in rats with chronic renal failure. In addition, the effects on calcium and phosphorus are minimal allowing the use of larger doses of this compound to suppress secondary hyperparathyroidism. Although no human studies have been conducted to this point, the fact that all three doses of 19-nor-1, 25- (OH) 2D2 were effective in suppressing PTH secretion, indicates a large therapeutic window for this compound. In summary, we have demonstrated that 19-nor-l, 25- (OH) 2D2, a new calcitriol analogue with low calcemic and phosphatide effect, is effective in suppressing parathyroid hormone in uraemic rats with secondary hyperparathyroidism. CHEMICALS OF BLOOD Normal Uremic Uremic + 1.25- (OH) 2D? 2 ng 4 ng 8 ng n = 8 n = 11 n = 13 n = 11 n = 13 Serum creatinine mg / dl 0.64 ± .02 * 1.15 ± .05 1.18 ± .06 1.12 ± .04 1.15 ± .07 ICa mg / dl 4.77 ± .07 4.81 ± .08 4.80 ± .10 4.95 ± .06 5.08 ±. 06 ++ CHEMICALS OF BLOOD (Cont.) Normal Uremic Uremic + l, 25- (OH) 2D? 2 ng 4 ng 8 ng n = 8 n = 11 n = 13 n = 11 n = 13 Phosphorus mg / dl 3.76 ± .27 5.57 ± .50 5.47 ± .52 7.45 ± .80 8.64 ± 1.15 * PTH pg / ml 40 ± 8.6 247 ± 83 152 ± 45 166 ± 40 90 ± 20 CHEMICALS OF BLOOD (cont) Normal Uremic uraemic + 19-nor-l.25- (OH) D2 8 ng 25 ng 75 ng n = 8 n = 11 n = 14 n = 12 n = 12 Serum creatinine mg / dl 0.64 ± .02 * 1.15 ± .05 1.20 ± .06 1.18 ± .05 1.16 ± .16 ICa mg / dl 4.77 ± .07 4.81 ± .08 4.79 ± .09 4.96 ± .05 4.96 ± .06 Phosphorus mg / dl 3.76 ± .27 5.57 ± .50 5.68 ± .57 5.98 ± .49 6.17 ± .68 PTH pg / ml 40 ± 8.6 247 ± 83 137 ± 47 111 ± 38 53 ± 16 * All data are average ± SEM, n = 11-14 per group. * P < 0.01 vs. uremic control. ++ P < 0.02 vs. uremic control.

Claims (14)

1. CLAIMS 1. - Method for treating a patient who has renal osteodystrophy while avoiding hyperphosphatemia, characterized in that it comprises administering to the patient a vitamin D compound that has the minimum effect on phosphorus in the patient's blood serum, the vitamin D compound is selected from a compound 19-nor-l, 25- (OH) 2D2 having the formula: wherein X1 and X2 each independently represents hydrogen or a protective hydroxy group, and wherein R is represented by the structure below: where the stereochemical center can have the configuration R or S, and where Z is chosen from Y, -OY, -CH2OY, -C = CY and -CH = CHY, where the double bond can have the cis or trans geometry , and where Y is chosen from hydrogen, methyl, -CR50 and a group of the structure:
2. R > R2 R3 - (CH2) m - C - (CH2) n- C -R5 R4 wherein m and n, independently represent integers from 0 to 5, wherein R 1 is chosen from hydrogen, hydroxy, protected hydroxy, fluorine, trifluoromethyl and C 1-5 alkyl, which may be straight or branched chain and optionally contain a protected hydroxy or hydroxy substituent and wherein each of R 2, R 3 and R 4, independently is chosen from hydrogen, fluorine, fluoromethyl and C 1-5 alkyl, which may be straight or branched chain and optionally contain a hydroxy substituent or protected hydroxy, and wherein R1 and R2 together represent an oxo group, or an alkylidene group, = CR2R3, or the group - (CH2) p, wherein p is an integer from 2 to 5, and wherein
3. R '"and nR1 * Jju U1n1tLUo &s LrCeppLrCeSsCeXnltLaainl u LUnÍ ygiruupuo Uo? XUo, or a group - (CH2) where q is an integer from 2 to 5, where R .5 represents hydrogen, hydroxy, protected hydroxy or alkyl with 1 to 5 carbon atoms wherein any of the groups at positions 20, 22 and 23 respectively in the side chain can be replaced by an oxygen atom 2. The method according to claim 1, characterized in that the compound Vitamin D is administered together with a pharmaceutically acceptable excipient 3. The method according to any of claims 1 or 2, characterized in that the vitamin D compound is in a solid or liquid vehicle ingesible by and non-toxic to the patient.
4. 4. - The method according to any of claims 1 to 3, characterized in that the vitamin D compound is the 25-dihydroxy-19-nor-vitamin D3
5. 5. - The method according to any of the claims 1 to 3, characterized in that the vitamin D compound is la-dihydroxy-19-nor-vitamin D3.
6. 6. - The method according to any of claims 1 to 3, characterized in that the vitamin D compound is the, 25-dihydroxy-19-nor-vitamin D2.
7. 7. - The method according to any of claims 1 to 3, characterized in that the vitamin D compound is la-dihydroxy-19-nor-vitamin D2.
8. 8. - The method according to any of claims 1 to 3, characterized in that the vitamin D compound is the 25-dihydroxy-19-nor-24-epi-vitamin D2.
9. 9. - The method according to any of claims 1 to 3, characterized in that the vitamin D compound is la-dihydroxy-19-nor-24-epi-vitamin D2.
10. 10. - The method according to any of claims 1 to 9, characterized in that the vitamin D compound is administered orally.
11. 11. The method according to any of claims 1 to 9, characterized in that the vitamin D compound is administered parenterally.
12. 12. - The method according to any of claims 1 to 9, characterized in that the vitamin D compound is administered topically.
13. 13. - The method according to any of the preceding claims, characterized in that the vitamin D compound is administered in an amount of 1 μg to about 500 μg per day to the patient.
14. 14. Use of a vitamin D compound as defined in claim 1, for the manufacture of a medicament for the treatment of a patient having renal osteodystrophy while avoiding hyperphosphatemia.