COMPOSITION FOR AND METHOD OF TREATING AIDS AND CERTAIN RELATED DISEASES

Abstract: A method for treating retroviral associated diseases, such as AIDS, in a patient, wherein a substituted 2'-deoxycytidine compound, such as, for example, 5-methyl-2'-deoxycytidine, is administered to the patient in a therapeutically effective amount, together with a deamination inhibitor of the deoxycytidine compound. Compositions for carrying out the method are also disclosed.

Description: COMPOSITION FOR AND METHOD OF TREATING AIDS AND CERTAIN RELATED DISEASES FIELD OF THE INVENTION The present invention relates to pharmaceutical com¬ positions containing 5-methyl-2'-deoxycytidine, 5- -chloro-2 1 - deoxycytidine, 5-fluoro-2'-deoxycytidine or 5-trifluoromethyl-2'-deoxycytidine, preferably with inhi¬ bitors of their deamination, and to a method for inhibi¬ ting the spread of the carrier state of Acquired Immune Deficiency Syndrome (AIDS) and as a cure for the AIDS diseased state. The compositions may have utility in the treatment of related disease states, such as multiple sclerosis and leukemia. BACKGROUND " OF THE INVENTION Diseases caused by Herpes and Herpes-like viruses are particularly widespread in man. Examples of Herpes viruses are Herpes simplex virus (HSV) Types 1 (HSV-1) and 2 (HSV-2) and Herpes varicella-zoster virus (VZV) that causes chicken pox in children and shingles in adults. Other examples of Herpes-like viruses are Ep- stein-Barr virus, Pseudorabies virus, Cytomegalo virus, Marek's dise'ase virus of chickens, equine abortion virus (EAV) and Lucke-frog virus. Herpes simplex viruses are strongly implicated in many pathological systems and include ocular (Kera- titis), cutaneous (including genital and oral), and sys¬ temic disseminated infections. One disease caused by the Herpes simplex virus Type 1 (HSV-1) is a particularly virulent form of encephalitis which, if not treated effectively, is usually fatal. Recurrent and persistent genital infections occur with HSV-2 that are widespread in the population and defy management so that these patients suffer great physical discomfort and psycho¬ logical distress. HSV-1 causes substantial discomfort to a large segment of the population. There is at this time SUB T no known way to manage recurrent infections or to combat this virus in its latent stage. Varicella-zoster is often the cause of morbidity in immunosuppressed patients such as kidney transplant reci¬ pients. Cytomegalo virus causes embryological abnormali¬ ties, perinatal neurological disease and great problems in the neonate; like zoster, it is a neurotropic virus. An extremely active area of the current medical re¬ search is the study of virus caused diseases, in parti¬ cular those induced by Herpes and Herpes-like viruses. An important part of this research is the development of selective antiviral agents for the treatment of these diseases. As will be discussed in more detail below, the major problem with the antiviral agents presentl avail¬ able is their tendency to undergo catabolism in the body and, more importantly, their toxicity towards uninfected cells; that is, their nonselectivity. The search for effective antiviral agents which exhibit specific antiviral activity against cells infec¬ ted with Herpes and Herpes-like viruses has met with varying degrees of success. In 1962, Kaufman (IDU Ther¬ apy of Herpes Simplex, Arch, Ophthalmol. 67, 583, 1962) investigated the antiviral activity of certain 5-halo- deoxyuridine compounds and found that 5-iodo-2'.-deoxyuri- dine (IdU) exhibits antiviral activity against HSV infec¬ tions of the eye. Subsequently, Heidelberger discovered that, while 5-fluorodeoxyuridine exhibits very little antiviral activity, 5-trifluoromethyl-2'deoxyuridine, or 5-trifluoro thymidine (F-jdT), does exhibit antiviral ac¬ tivity against infections of the eye. The compound F^ T is described and claimed in U.S. Pat. No. 3,201,387. Although IdU is effective against Herpes Keratitis it is less effective than F dT and is not as effective in systemic infections or in the treatment of Herpes genitalis. SHEET Despite exhibiting antiviral activity, these two compounds (IdU and F 3 dT) suffer from two major disadvan¬ tages. The first is that the compounds undergo rapid catabolism in the body which results in significant reduction of antiviral effectiveness of the compound. The second disadvantage is that the compounds exhibit toxicity towards uninfected cells which, in turn, re¬ sults in the generation of unpleasant and harmful side effects. IdU has been abandoned for the treatment of Herpes encephalitis because of its toxicity and its ineffectiveness, and F,dT has not been considered for the treatment of systemic infections. There are some approaches that involve direct intracranial injection of this compound for the treatment of encephalitis; how¬ ever, the studies are still at the stage of animal mo¬ dels. Furthermore, the approach to treatment appears to be associated with potential hazards for use in humans. Studies on various 5-substituted analogs of deoxy- uridine, including 5-methyl amino-2'-deoxyuridine, 5- thiocyanato-2'-deoxyuridine, 5-ethyl-2'-deoxyuridine, 5- propyl-2'deoxyuridine, 5-phenyl-2'-deoxyuridine and 5- allyl-2'-deoxyuridine have been reported which indicate that these compounds do exhibit antiviral activity against Herpes simplex in cell culture; however, the success of these compounds will likely remain limited to cell culture studies, in spite of the fact that they are non-toxic in culture, for they are substrates for the catabolic enzymes uridine and thymidine phosphorylase. Adenine arabinoside has been shown to decrease the incidence of death due to human encephalitis. However, the number of individuals with neurological sequelae was discouraging. That is, the drug decreased the mortality but increased the morbidity. Furthermore ara-A or ara- AMP is neither effective against recurrent genital Herpes nor does it decrease the incidence of latent virus infection. Phosphonacetic acid is effective in animal systems; however it must be administered in most cases very soon after infection, and is usually ineffec¬ tive if the onset of treatment is delayed to coincide with realistic intervals for consideration for use in humans. Another disadvantage is that it is accumulated in bone. Other drugs such as ara-T and 4-amino-5-iodo- deoxyuridine are in various stages of development and are far from being ready for use in clinical studies. In view of the capacity of viruses to mutate to re¬ sistance to a drug (as is the case with phosphonacetic acid) it is likely that ultimately viral chemotherapy will involve a combination of drugs that act via dif¬ ferent mechanisms. More recently, attention has turned to the study of deoxycytidine compounds as possible antiviral agents and, in particular, the 5-substituted analogs thereof. Greer et al. (Annals of the New York Academy of Sciences, Volume 255,359, 1975) have studied the anti¬ viral activity of 5-halo-2'-deoxycytidines, namely 5- bromo-2 1 -deoxycytidine (BrdC) and 5-iodo-2'-deoxycyti¬ dine (IdC). The studies have shown that these 5-halo-2'- deoxycytidine compounds possess a similar antiviral ac¬ tivity against HSV infected cells as that possessed by the corresponding 5-halo-2'-deoxyuridine compounds, but most importantly that the 5-halo-2'-deoxycytidine com¬ pounds are substantially less toxic towards uninfected cells than the deoxyuridine compounds. Kurimoto et al. Folia, Ophthalmol. Japan, 20, 49 (1969) have shown that IdC is more effective in the treatment of Herpes Kera- titis in humans than IdU. A drawback of the 5-halo-2'-deoxycytidine compounds is their tendency to undergo deamination in the presence of deaminating enzymes, such as cytidine deaminase. Such enzymes are usually present in the blood and catalyze the deamination of the 5-halo-2'-deoxycytidine compound to the corresponding 5-halo-2'-deoxyuridine compound. As a result of this deamination, uridine compounds are formed which do not display selectivity and which exhi¬ bit toxicity towards uninfected cells and generate un¬ pleasant and harmful side effects. Furthermore, deoxyuri¬ dine analogs are further degraded to metabolites that do not display antiviral activity. In order to overcome this problem of deamination, it has been ^ found necessary to employ a deamination inhibitor, and tetrahydrouridine (H,U) and 2'-deoxytetra- hydrouridine (H,dU) have been found particularly suit¬ able for this purpose. These two compounds are described in U.S. Pat. No. 4,017,606 (Hanze et al.). The anti-viral (HSV) activities of 4-N alkyl deriva¬ tives (methyl, ethyl, isopropyl) of IdC have been stu¬ died, Fox, Doberson and Greer, Antimicrobal Agents and Chemotherapy, Vol. 23, 465-476, 1983, and appears to be incorporated into viral DNA without deamination; that is, it is not necessary to coadminister dHΛJ or H,U. Studies have been recently reported of the antiviral activity of 5-methyl-2'-deoxycytidine -and 5-ethyl-2'-deoxy¬ cytidine. Stvugar (J. Med. Chem. Vol. 17, No. 3, 296, 1974) discovered that 5-ethyl-2'-deoxycytidine possesses only a low antiviral activity against HSV infected cells and no activity against vaccinia and vesicular stomatitis. Stu¬ dies by Lin and Prusoff (Abstracts of Papers, 174th ACS Meeting, American Chemical Society, Aug. 38-Sept. 2, 1977) have shown that 5-methyl-2'-deoxycytidine is less effective as an antiviral agent against HSV infected cells than 5-me- thyl-2'-deoxyuridine. Greer U.S. patent 4,210,638 discloses the use of 5-tri- fluoromethyl-2'-deoxycytidine, together with a cytidine deaminase inhibitor, to treat patients suffering from a disease caused by a Herpes or a Herpes-like virus. Further work has also suggested that 5-trifluoromethyl-2'-deoxycyti¬ dine can be used to treat solid tumors, and again the com- ' - ET dine can be used to treat solid tumors, and again the com¬ pound (also called F^methyl dC or CF-dC) would be admini¬ stered in connection with a cytidine deamination inhibitor such as tetrahydrouridine or 2'-deoxytetrahydrouridine. Publications have described that 5-methyl-2'-deoxy¬ cytidine is not incorporated as such in mammalian cells, even when co-administered with dH,U, whereas 5-bromo-2'- deoxycytidine and 5-iodo-2'-deoxycytidine are incorpora¬ ted into DNA. These studies utilize cells transfected with the gene encoding the pyrimidine nucleoside kinease of HSV-1 or HSV-2 so that the analogs would be phosphorylated to the nucleostide level. 5-fluoro-2*-deoxycytidine is incor¬ porated to only a very limited extent in normal cells, but is incorporated to a greater extent in tumor cells. The coadministration of dH,U increases the incorporation of 5FdC 25-fold. The effects of co-administering high levels of dH,U with FdC in two mouse tumor models has been studied. 4 5-Chloro-2'-deoxycytidine, when coadministered with dH,U or H,U, is not (less than 0.27 o ) incorporated into DNA of human cells in culture or in normal and tumor tissue of the mouse. SUMMARY OF THE INVENTION The present invention is directed to pharmaceutical compositions containing a therapeutically effective amount of a compound of the for vherein X is fluoro, chloro, CH 3 or CF-, together v.-ith. an inhibitor of cytidine deaminase and dCMP dea-ni- r-r.K , cυc as 2'-cp-oxytetrahyrouridine, as well as the v ~ e of z . co ~ ,pcsitions in the treatment or reve ion o£ reti"!. iral associa ed diseases, such «:: AIDS. E SHEET Preferred compounds of the above formula are 5- methyl2'-deoxycytidine (CH-dC), 5-chloro-2'-deoxycyti¬ dine (CldC), and 5-fluoro-2'deoxycytidine (FdC), with the most preferred compound being CH-dC. Based on the preferred compounds, it is believed that the compound 5-trifluoromethyl2'-deoxycytidine (CF 3 dC) could also be used in the practice of the present invention, but CF~dC is less preferred. As indicated, the preferred inhibitor is 2*-deoxytetrahydrouridine. DETAILED DESCRIPTION OF THE INVENTION The combination of 5-methyl-2'-deoxycytidine and 2'- deoxytetrahydrouridine should result in the incorpora¬ tion of 5-methyl-2'-deoxycytidine as such into the DNA of cells utilizing the RNA of HTLV-III as a template, and reverse transcriptase as the DNA polymerase. This enzyme, the RNA dependent polymerase, possesses a very low fidelity of DNA replication in contrast to the DNA dependent DNA polymerase utilized by T-helper cells that do not possess HTLV-III. It has been established that cells utilizing a DNA dependent DNA polymerase, such as normal T-cells or normal T-helper cells, do not incorporate 5-methyl-2'- deoxycytidiήe (5-CH 3 dC) or 5-chloro-2'-deoxycytidine (CldC) in their DNA even when both cytidine deaminase and dCMP deaminase are inhibited by the coadministration of 2'-deoxytetrahydrouridine. There is a mounting body of evidence that when cyto- sine adjacent to guanine is methylated at the 5-posi- tion, especially at promoter sites, there will be inter¬ ference with the formation of m-RNA (transcription) or DNA dependent formation of viral RNA copies. The methy¬ lated gene will thereby be turned-off by inappropriate incorporation of 5-CH 3 dC. It should be noted that 5- CH-jdC appears in DNA adjacent to deoxyguanosine as a result of the postpolymer methylation of certain deoxycy- tidines. It is not a result of the incorporation of HEET CH dCTP. This is the manner in which differential gene expression occurs naturally in eukaryotes. This method of regulation is exploited in the present invention for the purpose of selective viral chemotherapy. Thus, the inappropriate incorporation of 5-CH 3 dC into the DNA of HTLV-III infected T-cells due to the infidelity of retrovirus DNA dependent RNA polymerase will allow selective antiviral action by 5-CH g dC when deamination is inhibited at the nucleoside and nucleo- tide level by 2'-deoxytetrahydrouridine (2'-dH,U). Simi¬ lar results are obtained with the other deoxycytidine compounds of the present invention, when such compounds are so administered with inhibitors of their deamination. In the DNA sequence (considering a single strand only) of HTLV-III in which control or regulatory signals are likely to occur, 207o of the dinucleotides are GC or CG; indeed, of the 100 nucleotides prior to the region of DNA which is ultimately translated, 287o of the dinucleo¬ tides are CG or GC. An interesting aspect of this invention is that because ribavirin is a somewhat effective agent against HTLVIII, 5-methyl dC may also be substantially phosphory- lated in the target cells. The enzyme responsible for the activation (phosphorylation) of ribavirin (a guano- sine analog) is adenosine kinase; however, deoxyguano- sine-deoxycytidine kinase may also be involved in the activation of ribavirin. The Km and Ki values of 5-CH 3 dC with respect to deoxycytidine kinase was found to be only 2- to 9-fold higher than the Km value for deoxycytidine. Therefore, 5-CH 3 dC should be readily phosphorylated in T-helper cells. One of the novel aspects of this approach is that 5-fluorodeoxycytidine (5-FdC), when coadministered with 2'-deoxytetrahydrouridine, may also result in effective T TE ET selective inhibition of HTLV-III infected cells in view of the finding that 5-fluouro-deoxycytidine is incorpora¬ ted to only the extent of 0.2% into the DNA, utilizing the DNA dependent DNA polymerase of uninfected mammalian cells. It appears likely that 5-fluoro-deoxycytidine will be incorporated to a much higher extent into DNA of cells in which an RNA template and the reverse transcrip- tase are utilized in which 1 mistake/10 nucleotides is Q made rather than 1 mistake/10 nucleotides, as is the case with thfe DNA dependent DNA polymerase. It has been shown that the incorporation of 5-FdC into DNA inhibits the post polymer methylation of DNA. Therefore, FdC will also affect gene expression, but in an opposite way than 5-CH dC does. The disruption of gene regulation by this mechanism should also eliminate the carrier state of HTLV-III in T-helper cells. An indication that the inhibition of the methyla¬ tion of DNA may be an important target for viral inhibi¬ tion is the fact that certain adenosine analogs which are very effective inhibitors of both DNA and RNA viruses are potent inhibitors of S-adenosylhomocystine hydrolase. Inhibition of this enzyme prevents the regene¬ ration of S-adenosylmethionine which is required to transfer a methyl group to DNA. This is a function of DNA cytosine methyltransferase for- which S-adenosylme¬ thionine is a cofactor. An advantage of the use of 5-CH-dC is that it should display very little toxicity to the patient. If it is deaminated, thymidine will be formed which is a normal metabolite—although it can be inhibitory at ex¬ tremely high concentrations (as dTTP). There is an in¬ ternal control which makes it unlikely that generally toxic levels of TTP will be formed, for dCMP deaminase is not only inhibited by 2'deoxytetrahydrouridine, it is also regulated by TTP. TTP also end product inhibits nucleoside diphosphate reductase and thymidine kinase. One advantage of elevated TTP, which may be formed from EET 5-CH-.dC, is that it will lead to the perturbation of precursor pools for the synthesis of proviviral DNA, thereby resulting in even greater mistake levels in polymer synthesis. Another advantage of utilizing 5- CH-.dC is that any thymidine formed may, as TTP, inhibit dCMP deaminase, CTP synthetase, and nucleoside diphos- phate reductase. Inhibition of CTP synthetase and the reductase would result in lowering pools of dCTP, which possess the potential to compete with the incorporation of the 5-su stituted analogs of deoxycytidine. In some situations it may be advantageous to use a hyperthermia treatment after the administration of CH-dC, as the elevated temperatures should promote the deamination of incorporated methylated cytosine to form thymine in DNA resulting in abnormal guanine-thymine base pairs; there¬ by resulting in further disruption of the virus. It is possible that when CldUTP or F^TTP are formed from 5-CldC or 5-CF 3 dC, respectively, they may also act as inhibitors of the reductase, and enhance their incorpora¬ tion into DNA by lowering the levels of competing dCTP. A distinct advantage of the use of 5-methyl-2'- deoxycytidirie and 5-chloro-2'-deoxycytidine is that they will not be catabolized by enzymes of pyrimidine catabo- lism (the nucleoside phosphorylases) when their deamina¬ tion is prevented. This catabolis ' m is a problem en- counted with thymidine and uridine analogs. Because no incorporation of 5-CH^dC or 5-CldC has been demonstrated in normal human, cells, the selectivity should be very strong. The problems that this invention may solve will be to provide a cure for a morbid disease which is usually fatal. The present invention should interfere with the dissemination of infection of this highly infectious disease, AIDS. This invention should not only be effective against HTLV-III, but against other retrovirus related disease states such as leukemia and multiple sclerosis, if in¬ deed it is found that HTLV-I is a causative agent of multiple sclerosis, as a recent publication suggests. Another possible advantage of the present invention is that many leukemic states, such as certain T-cell leukemias, have elevated levels of dCMP deaminase; there¬ fore, the addition of 2'-dH,U may interfere with the unique and possibly essential metabolic event in these cells—thereby attacking the disease state at an entire- ly different target end point. Because no known cure exists for AIDS (and, for that matter, for multiple sclerosis), the present inven¬ tion may offer a cure where none exists. The short¬ comings of imminological approaches are that the virus is highly mutable and may change antigenic properties so that an antibody directed against a specific isolate may not be generally effective. In contrast, the present invention exploits rather than is endangered by the infidelity of viral DNA replication. The infidelity of retrovirus replication is due, in part, to the fact that the viral RNA dependent DNA polymerase lacks a 3' to 5' proof-reading exonuclease which is active in DNA-direc- ted DNA synthesis (i.e., active in uninfected cells). Another factor contributing to the infidelity of retro¬ virus DNA replication is that a single strand of nucleic acid (RNA) rather than a helical double strand (DNA) acts as a template for the synthesis of the polymerase. To date, no agent has been found to alter the clinical course of the disease AIDS, and this includes inhibitors of reverse transcriptase and effectors of the immune re¬ sponse. When 5-chloro-2'-deoxycytidine is coadministered with 2'-dH,U, no (less than 0.5%) 5-CLdC as such is found in DNA. Only 5-chloro-2'-deoxyouridine derived from 5-CLdC is seen. The extent of 5-chloro-2'-deoxyouri¬ dine substitution for thymidine was 32%. It is conceivable that viral infections which be¬ come localized in the brain would be amenable to a combination treatment with 5-chloro-2'-deoxycytidine, 2'- -deoxytetrahydraouridine and x-ray in order to obtain selective sensitization of the infectious centers at the disease sites. Pharmaceutical compositions for intravaneous, subcu¬ taneous, intramuscular, oral or intraperitoneal adminis¬ tration are included in the present invention. These pharmaceutical compositions will contain viral inhibi¬ tory amounts af 5-CH 3 dC, FdC, CldC or 5-F 3 methyl dC, and dH U or other deamination inhibitor, together with a pharmaceutically acceptable carrier or diluent. While the components of the composition may be administered to a patient separately, with the dH/U administered up to a half hour before or fifteen minutes after the 5-substi- tuted deoxyouridine compound, it is preferred to coadmin- ister the active ingredients as a mixture. The concentra¬ tion of each of the active ingredients may vary from about 0.01 to about 15% by weight, depending upon the route of administration, the frequency of administra¬ tion, the severity of the condition, the age, weight and general physical condition of the patient being treated. Alternatively, a more concentrated solution could be used, e.g., 35 grams/100 ml, or a slow I.V. infusion of 0.1 to 257o (or higher) concentration could be used. When used for intravenous injection, the concentra¬ tion of the active components (the 5-substituted deoxycy¬ tidine compound and the dH,U) will each vary from about 0.05 to about 5%, w/v, preferably about 0.1 to 0.5% w/v. When the composition is administered by the intra¬ peritoneal mode of administration, such as, for in¬ stance, intraperitoneal administration for animal stu¬ dies, aqueous solution of 5CH dC, CldC, FdC, or F^methyl dC and dH,U, having a concentration generally varying from about 0.5 to 5% w/v, and preferably from 1% w/v, for each compound can be utilized. For intramuscular injection, the same conditions as described above for the intraperitoneal mode of administration will be uti¬ lized. For oral administration, the concentration of the active ingredients will generally be from 0.05 to 10 weight percent each, preferably about 0.5 to 5 weight percent each, and more preferably each will be present in an amount of about 1 to 2 weight percent. Other methods of administration may be used. Sup¬ positories may be used for sustained release purposes, and slowrelease surgical implants are also envisaged. The pharmaceutically acceptable carriers or di¬ luents employed in the compositions of the present inven¬ tion may be any compatible non-toxic material suited for mixing with the active compounds. When the composition is in a form suitable for parenteral use, for example, intramuscularly or intravenously, the carrier, which pre¬ ferably is an aqueous vehicle, may also contain other conventional additives, such as a suspending agent, for example, methyl cellulose or polyvinylpyrrolidone (PVP), and a conventional surfactant. For oral administration, the compositions can be formulated as aqueous solutions, suspensions, capsules, or tablets, suitably containing appropriate carriers or diluents, for example, lactose, starch and/or magnesium stearate for flavoring agents, syrups, sweeteners, and/or coloring materials as custo¬ marily used in such preparations. A preferred pharmaceutical composition provides the patient with a total i.v. dosage* of from 3 to 5 ml (cc) per dosage calculated on 70 kg body weight of the patient. The inhibitor which is coadministered with the 5- substituted deoxycytidine compound must inhibit both cy¬ tidine deaminase and dCMP deaminase under most condi¬ tions. This is so that the inhibitor can prevent deamina¬ tion of the nucleoside and the corresponding nucleotide. For certain situations, such as, for example, if the dCMP deaminase is at a low level, it may be in order to administer tetrahydrouridine in place of some or all of the 2'-deoxytetrahydrouridine. The patient will preferably be given drugs i.v. or i.m. or in an oral or suppository form or in a slow release form. A slow release administration of the 5-sub- stituted analogs of deoxycytidine and of deoxytetrahy¬ drouridine (or tetrahydrouridine) may be particularly advantageous. """ Different routes may be used for indivi¬ dual drugs in one treatment protocol. It may be necessary to administer inhibitors of de novo pyrimidine biosynthesis to decrease further normal metabolite pools of dCTP which could compete for the incorporation of CH 3 dCTP, CICdTP, FdCTP, or F 3 _nethyldCTP into HTLV DNA. These additions would preferably be in the form of pretreatments and could include PALA to inhibit aspartyl transcarbamylase, and/or deazauridine to inhibit CTP synthetase (this is also an inhibitor of nucleoside deaminases) and/or the glutamyl transferase inhibitors azaserine or DON, which also inhibit CTP synthetase and/or hydroxyurea or 2'-chloro-deoxyadeno- sine, which inhibit nucleoside diphosphate reductase, and/or high doses of thymidine, or, more preferably, in view of catabolis , 5-CH 3 dC + tetrahydrouridine, as a source of high doses of thymidine. For example, PALA in 10 ml ampules containing PALA disodium (1.0 gram) with Edetate disodium (1 mg) and NaOH to adjust pH to 6.5 to 7.5 will be given to an AIDS, leukemia, or MS patient at a range of 2 mg to 150 mg/kg per dose, preferably 5 to 20 mg/kg per dose and, more likely, 10 mg/kg per dose. Twelve to thirty-six hours later, preferably 18 to 26 and, most likely, 24 hours later, deazauridine, at a dose of 5-80 mg/kg per dose, preferably 10 to 40, more likely 30 mg/kg, would e ' EET be administered. This would then be immediately fol¬ lowed, for example, by the addition of 5-CH dC at a dose of 100 mg to 1000 mg/kg, plus tetrahydrouridine at a dose range from 5 to 500 mg/kg, preferably 50 to 300 mg/kg and, more likely, 80 mg/kg. The ratio of H,U to CH 3 dC will range from 2:1 to 0.2:1, preferably 1:1 to 0.5:1 and, more likely, 0.75:1. Three to 12 hours later, preferably 4 to 8 hours, more likely 6 hours later, the series of administration of the 5-substituted deoxycytidine compound and dH,U will begin. The dose of 5-substituted deoxycytidine analogs (not including FdC) will range from 50 to 1000 mg/kg per dose, preferably 75 to 500 mg/kg, more likely 150 mg/kg. The dose of dH 4 U will be similar to that of H 4 U given with CH«dC in the pretreatment described above, except when FdC is utilized. The ratios are, however, different; namely, the ratio of dH,U to CH 3 dC, CldC or F inethyl dC will range from 1:10 to 1:1, more usually, 1:5 to 1:1.5, and, more likely, 1:2. When FdC is administered, the dose will be in the range of 5 to 80 mg/kg, preferably 10 to 20 mg/kg and, more likely, 12 to 15 mg/kg. The dose of dH,U or H,U would be 15' to 100 mg/kg, preferably 20 to 30 mg/kg, more likely 25 mg/kg. This dose will be repeated at 6 to 18 hour inter¬ vals, more usually 8 to 12, preferably 10 hour inter¬ vals. The period of repeated administration of 5-substi¬ tuted analogs of deoxycytidine + dH,U or other deamina¬ tion inhibitor will be 20 to 60 hours, more usually 30 to 50 hours, more likely 34 to 48 hours. Usually the 5-substituted analogs of deoxycytidine + dH.U will be administered in 3 to 4 doses, 8 to 12 hours apart, before initiating another cycle of treatment (including the pretreatment to inhibit the de novo pathway). The interval between PALA/deazauridine/hydroxyurea/- 5CH dC + H,U pretreatment therapy and the administration of 5-substituted analogs of deoxycytidine, the frequency UBSTITUTE SHEET of administration, the choice between continuous infu¬ sion vs. bolus doses and the length of the interval between each cycle of treatment is determined by skilled estimation, drawing upon previous experiences, and obse¬ rvations using this regimen of therapy. If toxicity is encountered in a cycle of drug treat¬ ment, then CH g dC + H,U or thymidine or deoxycytidine + H U or dH.U may be administered 6 to 12 hours after cessation of the cycle of treatment. Less desireable would be the ^ administration of these rescue antagonists during the treatment cycle, although adding them towards the end of the cycle would be more preferable than if added in the middle of the treatment schedule. Thymi¬ dine .or CH 3 dC would be added at a dose of 50 to 500 mg/kg, more likely 100 to 400 mg/kg, preferably 150 mg/kg. Deoxycytidine would be added at a dose of 25 to 200 mg/kg, preferably 50 to 100 mg/kg. When CH 3 dC or dC is utilized, it will be coadministered with tetrahydrou¬ ridine at a ratio of tetrahydrouridine to pyrimidine deoxyribonucleoside of 1:05 to 1:5. Deoxycytidine may also be coadministered with deoxytetrahydrouridine for the purpose of antagonism or rescue. -This rescue proto¬ col would be repeated 2 to 5 times at 6 to 18 hour inter¬ vals. e- . as is-πτuτε SHEET The Table set forth below sets forth in general terms the dosage, in milligrams per killogram, which will normally be utilized in the pretreatment step, the treatment step and the rescue step. DOSAGE, mg/kg Most Agent General Preferred Preferred PALA 2-150 5-20 10 Deazauridine ^ 5-80 10-40 15-35 2 '-Chlorodeoxya- denosine 5-200 10-50 15-45 or Pre- Hydroxyurea 5-80 10-40 15-35 Treat- or ment Thymidine 100-1000 100-500 150 or CH 3 dC 100-1000 100-500 .150 + H 4 U 5-500 . 50-300 80 CH 3 dC ie Cldc or 50-1000 75-500 150 * F-methyldC Treat¬ or ment FdC + 5-80 10-20 - 12-15 - dH 4 U 15-100 . * 20-30 25 CH 3 dC 50-500 100-400 150 + H 4 U 10-75 25-50 30 or Thymidine 1 50-500 100-400 150 Rescue or Deoxycytidine 25-200 50-100 75 -:- dH,.U 5-50 10-40 25 .--_£.?-!' Based on the findings reported in the Fox, Doberson and Greer paper mentioned above, it appears that 4-N alkyl derivatives of deoxycytidine compounds used in the present invention would also be effective against the retroviral associated diseases, and that these 4-N alkyl derivatives would not require the coadministration of H 4 U or other deaminatio " . inhibitor. These 4-N alkyl derivatives could be used in the same amounts as set forth in the above table for the corresponding unalkyla- ted compounds, and may well be effective against the same retroviral ^ associated diseases, especially AIDS. It is anticipated that the same methods of administration would be utilized. It is- important that the substitutions at the 4-N posi¬ tion do not impair DNA-protein interactions at the 5-posi- tion. EXAMPLE 1 This example relates to how the present invention could be used to treat a patient suffering from AIDS. The patient would first be subjected to a pretreatment, involving the i.v. administration of PALA at a level of 10 mg/kg per dose, with the PALA in 10 ml ampoles containing PALA disodium (1.0 gm) with Edetate disodium (1 mg) and NaOH to adjust pH to 6.5 to 7.5. Twenty-four hours later deazauridine would be i.v. administered at a level 30 mg/kg per dose. The deazauridine administration would be immediately followed b} r the i.v. administration of 5-CH 3 dC in an amount of 150 mg/kg/dose plu^ tetrahy¬ drouridine in an amount of 150 mg/kg/doεe. Six hours later, the administration of the composi¬ tion of the present invention will begin. CH 3 C would be coadir.inistered in an amount of 150 iπg/kg/doεe, together v?ith 75 τ.:g/kg/cose of H^U, y i.v. administration- The dose .ill be repeated at 10 hour intervals for a total af-mini≤txation ti..e of 40 hours. Following the administration, if any toxicity were noted the patient would be subjected to a rescue regime involving the i.v. administration of a mixture of deoxy¬ cytidine and 2'-deoxytetrahydrouridine, in an amount of 75 mg/kg/dose of the deoxycytidine and 25 mg/kg/dose of the 2'-deoxytetrahydrouridine. This rescue would begin 10 hours after cessation of the cycle of treatment with the composition of the present invention, and the rescue protocol would be repeated three times at 12 hour inter¬ vals. All of the i.v. administration mentioned above would involve the intravenous administration of sterile saline solutions of the indicated compounds. SUBSTITUTE SHEET

Claims: IN THE CLAIMS 1. A method for the treatment or prevention of retroviral associated diseases in a patient, said method comprising administering to said patient a therapeutical¬ ly effective amount of a compound of the formula: wherein X is luoro, chloro, CH g or CF 3 , and a deamination inhibiting amount of an inhibitor of deamination of said compound and metabolic products thereof. 2. Method of claim 1, wherein said compound is selected from the group consisting of 5-methyl-2'-deoxy¬ cytidine, 5-chloro-2'-deoxycytidine, and 5-fluoro-2'- deoxycytidine. 3. Method of claim 1, wherein X is methyl. 4. Method of claim 1, wherein said inhibitor is 2'- deoxytetrahydrouridine. 5. Method of claim 1, wherein said disease is Acquired Immune Deficiency Syndrome (HTLV-III). 6. Method of claim 1, wherein X is chloro or fluoro. 7. Composition for the treatment of retroviral asso¬ ciated diseases, said composition comprising an effec¬ tive amount of a compound of the formula: ET wherein X ^ is methyl, chloro, fluoro or trifluorome- thyl, and a deamination-inhibiting amount of an inhibi¬ tor of cytidine deaminase and dCMP deaminase. 8. Composition of claim 7, wherein said compound is 5-methyl-2'-deoxycytidine administered in an amount of from 50 to 1000 mg/kg per dose. 9. Composition of claim 8, wherein said inhibitor is 2'-deoxytetrahydrouridine, which is administered in an amount of from 75 to 500 mg/kg/dose. 10. Composition of claim 9, wherein the ratio of 2*- deoxytetrahydrouridine to 5-methyl-2'-deoxycytidine is 1:10 to 1:1. 11. Composition of claim 7, wherein said compound is 5-chloro-2'-deoxycytidine or 5-fluoro-2'-deoxycyti¬ dine. 12. Composition of cla'i 11, wherein said inhibitor is 2'-deoxytetrahydrouridine. 13. Composition for the treatment of AIDS, compri¬ sing 50 to 1000 mg/kg/dose of 5-methyl-2'-deoxycytidine and 50 to 250 mg/kg/dose of 2'-deoxytetrahydrouridine and a pharmaceutically acceptable carrier. S UBSTITUTE SHEET 14. Composition of claim 13, wherein said composi¬ tion contains 75 to 500 mg/kg/dose of said 5-methyl-2'- deoxycytidine and 75 to 200 mg/kg/dose of said 2*-deoxy- tetrahydrouridine. 15. A method for the treatment or prevention of retroviral associated diseases in a patient, said method comprising administering to said patient a therapeutical¬ ly effective amount of a compound of the formula: wherein X is fluoro, chloro, CH 3 or CF 3 , and each of - i and R« are independently hydrogen or lower alkyl, under conditions wherein deamination of said compound and metabolic products thereof are substantially preven¬ ted. 16. Method of claim 15, wherein R., is hydrogen and R 2 is selected from the group consisting of methyl, ethyl and isopropyl, so that said compound is resistant to deamination.

Inventors: GREER SHELDON B, PARKS WADE P, GREER, SHELDON, B., PARKS, WADE, P.
Applicants: GREER SHELDON B, PARKS WADE P, GREER, SHELDON, B., PARKS, WADE, P.
Application year: 1987
Main classification: A61K31
IPC codes: C07H19