Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The efficacy of pre- and postexposure treatment with the antiviral compound (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA) was tested against simian immunodeficiency virus (SIV) in macaques as a model for human immunodeficiency virus (HIV). PMPA was administered subcutaneously once daily beginning either 48 hours before, 4 hours after, or 24 hours after virus inoculation. Treatment continued for 4 weeks and the virologic, immunologic, and clinical status of the macaques was monitored for up to 56 weeks. PMPA prevented SIV infection in all macaques without toxicity, whereas all control macaques became infected. These results suggest a potential role for PMPA prophylaxis against early HIV infection in cases of known exposure.
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PMID:Prevention of SIV infection in macaques by (R)-9-(2-phosphonylmethoxypropyl)adenine. 1698 28

The (S)- and (R)-enantiomers of acyclic purine nucleoside phosphonate analogs (i.e., 3-hydroxy-2-phosphonomethoxypropyl [HPMP] derivatives, 3-fluoro-2-phosphonomethoxypropyl [FPMP] derivatives, and 2-phosphonomethoxypropyl [PMP] derivatives of adenine [A], 2-aminopurine, 2,6-diaminopurine [DAP], and guanine [G]) have been synthesized and evaluated for antiviral activity. As a rule, the HPMP derivatives proved effective against DNA viruses but not RNA viruses or retroviruses. In particular, (S)-HPMPA, (S)-HPMPDAP, and (R)- and (S)-HPMPG were exquisitely inhibitory to herpes simplex virus type 1 (50% effective concentrations, 0.63, 0.22, 0.10, and 0.66 microM, respectively). The FPMP and PMP derivatives showed marked inhibitory activities against retroviruses but not DNA viruses. The (S)-enantiomer of FPMPA and the (R)-enantiomer of PMPA were approximately 30- to 100-fold more effective against human immunodeficiency virus and Moloney murine sarcoma virus (MSV) than their enantiomeric counterparts. In contrast, both (S)- and (R)-enantiomers of the DAP and G derivatives proved equally effective against retroviruses, except for (R)-PMPDAP, which was 15- to 40-fold more inhibitory than (S)-PMPDAP. (R)-PMPDAP emerged as the most potent and selective inhibitor of MSV-induced transformation of murine C3H/3T3 cells and human immunodeficiency virus-induced cytopathicity in MT-4 and CEM cells (50% effective concentration, approximately 0.1 to 0.6 microM). When administered intraperitoneally at a single dose as low as 2 mg/kg, (R)-PMPDAP efficiently decreased MSV-induced tumor formation in newborn NMRI mice and significantly increased the survival time of MSV-infected mice. In addition, upon oral administration to MSV-infected mice, (R)-PMPDAP showed marked antiretroviral efficacy.
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PMID:Differential antiherpesvirus and antiretrovirus effects of the (S) and (R) enantiomers of acyclic nucleoside phosphonates: potent and selective in vitro and in vivo antiretrovirus activities of (R)-9-(2-phosphonomethoxypropyl)-2,6-diaminopurine. 845 66

The long-term therapeutic and toxic effects of 9-[2-(phosphonomethoxy)propyl]adenine (PMPA) were evaluated in simian immunodeficiency virus (SIV)-infected newborn rhesus macaques. Four untreated SIV-infected newborn macaques developed persistently high levels of viremia, and three of the four animals had rapidly fatal disease within 3 months. In contrast, long-term PMPA treatment of four newborn macaques starting 3 weeks after virus inoculation resulted in a rapid, pronounced, and persistent reduction of viremia in three of the four animals. Emergence of virus with fivefold-decreased susceptibility to PMPA occurred in all four PMPA-treated animals and was associated with the development of a lysine-to-arginine substitution at amino acid 65 (K65R mutation) and additional mutations in the reverse transcriptase; however, the clinical implications of this low-level drug resistance are nuclear. No toxic side effects have been seen, and all PMPA-treated animals have remained disease-free for more than 13 months. Our data suggest that PMPA holds much promise for the treatment of human immunodeficiency virus-infected human infants and adults.
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PMID:9-[2-(Phosphonomethoxy)propyl]adenine therapy of established simian immunodeficiency virus infection in infant rhesus macaques. 891 70

From a side-by-side comparative study, the acyclic nucleoside phosphonates (R)-9-(2-phosphonylmethoxypropyl)adenine [(R)-PMPA] and 9-(2-methylidene-3-phosphonomethoxypropyl)guanine (MDL 74,968) proved more selective in their inhibitory effect on human immunodeficiency virus types 1 and 2, feline immunodeficiency virus, and Moloney murine sarcoma virus (MSV) in cell cultures than the 9-(2-phosphonylmethoxyethyl) derivatives of adenine (PMEA) and guanine (PMEG). In particular, PMEG proved quite toxic. PMEA, (R)-PMPA, and MDL 74,968 afforded a marked delay in MSV-induced tumor initiation in MSV-infected newborn NMRI mice and substantially delayed associated animal death at doses as low as 4 to 10 mg/kg of body weight. Treatment of the NMRI mice with PMEA, (R)-PMPA, and MDL 74,968 at 25 or 50 mg/kg resulted in a high percentage of long-term survivors.
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PMID:Antiretroviral activities of acyclic nucleoside phosphonates [9-(2-phosphonylmethoxyethyl)adenine, 9-(2-phosphonylmethoxyethyl)guanine, (R)-9-(2-phosphonylmethoxypropyl)adenine, and MDL 74,968] in cell cultures and murine sarcoma virus-infected newborn NMRI mice. 905 2

(R)-9-(2-Phosphonylmethoxypropyl)adenine (PMPA) acts as a reverse transcriptase inhibitor of retroviruses and has been shown to be effective against acute simian immunodeficiency virus (SIV) infection in macaques. To study its efficacy at different stages of infection, we tested PMPA in cynomolgus macaques (Macaca fascicularis) that had been chronically infected with SIVMne for at least 19 weeks before treatment was begun. PMPA was administered subcutaneously in a single daily dose of either 30 or 75 mg/kg body weight for 28 days. Within < or = 2 weeks of treatment, PMPA in both dosing regimens reduced SIV levels by >99% in the plasma or peripheral blood mononuclear cells; in some macaques SIV levels were reduced to below the lower quantitation limit. At a dose of 30 mg/kg/day PMPA was well tolerated, causing no side effects while increasing the mean CD4+ cell counts in animals that received this dose. Thus PMPA seems to be a promising agent for use against retroviral infections.
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PMID:Effects of (R)-9-(2-phosphonylmethoxypropyl)adenine monotherapy on chronic SIV infection in macaques. 916 39

The immunomodulatory properties of (R)-enantiomer of 9-(2-phoshonomethoxypropyl)adenine ((R)-PMPA), one of the most potent acyclic nucleotide analogs effective against human immunodeficiency virus (HIV), were investigated under in vitro conditions using murine peritoneal macrophages. Remaining without influence on interferon-gamma and interleukin-2 expression, (R)-PMPA dramatically stimulated in a concentration- and time-dependent manner the secretion of tumor necrosis factor alpha (TNF-alpha) and interleukin-10. It also substantially augmented the production of nitric oxide (NO) induced by exogenous interferon-gamma. Inhibitory experiments using neutralizing antibodies against TNF-alpha and/or interleukin-10 demonstrated that these two cytokines are major factors responsible for triggering the underlying mechanism(s) leading to enhanced NO production. The novel findings on the immunomodulatory potential of acyclic nucleotide analogs are discussed in the context of their possible implication in antiviral therapeutic efficacy.
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PMID:Antiretroviral agent (R)-9-(2-phosphonomethoxypropyl)adenine stimulates cytokine and nitric oxide production. 927 86

Mathematical modeling of viral replication dynamics, based on sequential measurements of levels of virion-associated RNA in plasma during antiretroviral treatment, has led to fundamental new insights into human immunodeficiency virus type 1 pathogenesis. We took advantage of the simian immunodeficiency virus (SIV)-infected macaque model to perform detailed measurements and mathematical modeling during primary infection and during treatment of established infection with the antiretroviral drug (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA). The calculated clearance half-life for productively infected cells during resolution of the peak viremia of primary infection was on the order of 1 day, with slightly shorter clearance half-lives calculated during PMPA treatment. Viral reproduction rates upon discontinuation of PMPA treatment after 2 weeks were approximately twofold greater than those obtained just prior to initiation of treatment in the same animals, likely reflecting accumulation of susceptible target cells during treatment. The basic reproductive ratio (R0) for the spread of SIV infection in vivo, which represents the number of productively infected cells derived from each productively infected cell at the beginning of infection, was also estimated. This parameter quantifies the extent to which antiviral therapy or vaccination must limit the initial spread of virus to prevent establishment of chronic disseminated infection. The results thus provide an important guide for efforts to develop vaccines against SIV and, by extension, human immunodeficiency virus.
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PMID:Viral dynamics of primary viremia and antiretroviral therapy in simian immunodeficiency virus infection. 931 31

This article describes several approaches to a selective therapy of virus infections: (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU [brivudin]) for the therapy of herpes simplex virus type 1 and varicella-zoster virus infections: (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC [cidofovir]) for the therapy of various DNA virus (i.e., herpesvirus, adenovirus, papillomavirus, polyomavirus, and poxvirus) infections; 9-(2-phosphonylmethoxyethyl)adenine (PMEA [adefovir]) for the therapy of retrovirus, hepadnavirus, and herpesvirus infections; (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA) for the therapy and prophylaxis of retrovirus and hepadnavirus infections; and nonnucleoside reverse transcriptase inhibitors (NNRTIs), such as tetrahydroimidazo[4,5,1-jk][1,4]-benzodiazepin-2(IH)-one and -thione (TIBO), 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT), alpha-anilinophenylacetamide (alpha-APA), and 2',5'bis-O-(tert-butyldimethylsilyl)-3'-spiro-5"-(4"-amino-1",2"-oxat hiole- 2",2"-dioxide)pyrimidine (TSAO) derivatives, and thiocarboxanilides for the treatment of human immunodeficiency virus type 1 (HIV-1) infections. For the clinical use of NNRTIs, some guidelines have been elaborated, such as starting treatment with combinations of different compounds at sufficiently high concentrations to effect a pronounced and sustained suppression of the virus. Despite the diversity of the compounds described here and the different viruses at which they are targeted, they have a number of characteristics in common. As they interact with specific viral proteins, the compounds achieve a selective inhibition of the replication of the virus, which, in turn, should be able to develop resistance to the compounds. However, as has been established for the NNRTIs, the problem of viral resistance may be overcome if the compounds are used from the start at sufficiently high doses, which could be reduced if different compounds are combined. For HIV infections, drug treatment regimens should be aimed at reducing the viral load to such an extent that the risk for progression to AIDS will be minimized, if not avoided entirely. This may result in a real "cure" of the disease but not necessarily of the virus infection, and in this sense, HIV disease may be reduced to a dormant infection, reminiscent of the latent herpesvirus infections. Should virus replication resume after a certain time, the armamentarium of effective anti-HIV and anti-herpesvirus compounds now available, if applied at the appropriate dosage regimens, should make the virus return to its dormant state before it has any chance to damage the host. It is unlikely that this strategy would eradicate the virus and thus "cure" the viral infection, but it definitely qualifies as a cure of the disease.
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PMID:In search of a selective antiviral chemotherapy. 933 68

Bis(isopropyloxymethylcarbonyl) 9-R-(2-phosphonomethoxypropyl)adenine [bis(POC)PMPA] has been identified as a novel prodrug of PMPA. The anti-human immunodeficiency virus activity of bis(POC)PMPA was >100-fold greater than that of PMPA in both an established T-cell line and primary peripheral blood lymphocytes. This improved efficacy was shown to be due to a rapid intracellular uptake of the prodrug resulting in an increased intracellular accumulation of PMPA diphosphate (PMPApp), the pharmacologically active metabolite. PMPApp levels in bis(POC)PMPA-treated cells exceeded by >1,000-fold the levels seen in cells treated with unmodified PMPA in both resting and activated peripheral blood lymphocytes. Significant differences in the intracellular catabolism of PMPA metabolites were noted between the resting and activated lymphocytes. The half-life for the disappearance of PMPApp, derived from either bis(POC)PMPA or PMPA, was 12 to 15 h in the activated lymphocytes and 33 to 50 h in the resting lymphocytes. This long persistence of PMPApp, particularly in resting lymphocytes, may be unique to the nucleoside phosphonate analogs and indicates that effective levels of the active metabolite can be achieved and maintained with relatively infrequent administration of the parent drug.
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PMID:Anti-human immunodeficiency virus activity and cellular metabolism of a potential prodrug of the acyclic nucleoside phosphonate 9-R-(2-phosphonomethoxypropyl)adenine (PMPA), Bis(isopropyloxymethylcarbonyl)PMPA. 951 41

The pharmacokinetics, bioavailability, and metabolism of the anti-human immunodeficiency virus nucleotide analog 9[(R)-2-(phosphonomethoxy)propyl]adenine (PMPA) were determined in beagle dogs following intravenous, intraperitoneal, and oral administration. Fasted male beagle dogs (n = 5) were pretreated with pentagastrin and received PMPA (10 mg/kg of body weight) by the intravenous and oral routes with a washout period of 1 week between doses. A further group of male dogs received PMPA as a single dose via the intravenous (1 mg/kg; n = 5) and the intraperitoneal (10 mg/kg; n = 3) routes, with 1-week washout period between doses. The concentrations of PMPA in plasma and urine were determined over 48 h postdosing by fluorescence derivatization and high-performance liquid chromatography (HPLC). The potential for metabolism or biliary excretion of PMPA was evaluated in a dog with a chronic indwelling bile cannula. Urine, feces, and bile were collected at intervals over 48 h following the intravenous administration of [14C]PMPA (10 mg/kg; 55 microCi/kg). The concentrations of PMPA in plasma after intravenous injection were best described by an open two-compartment model with a terminal half-life of approximately 10 h. PMPA was excreted unchanged in urine (70%); recovery in feces (0.42%) or bile (0.26%) was negligible. The plasma clearance of PMPA (0.28+/-0.05 liter/h/kg) was substantially greater than the glomerular filtration rate in this species, suggesting active tubular secretion of PMPA. No metabolites of [14C]PMPA were observed in urine, feces, or bile on the basis of HPLC with radioactive flow detection. The remainder of the dose was probably excreted unchanged in urine beyond 48 h postdosing. The mean+/-standard deviation observed bioavailabilities of PMPA following oral and intraperitoneal administration at 10 mg/kg were 17.1%+/-1.88% and 73.5%+/-10.5%, respectively.
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PMID:Pharmacokinetics and bioavailability of the anti-human immunodeficiency virus nucleotide analog 9-[(R)-2-(phosphonomethoxy)propyl]adenine (PMPA) in dogs. 951 52


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