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Ugaonkar SR, Clark JT, English LB, Johnson TJ, Buckheit KW, Bahde RJ, Appella DH, Buckheit RW, Kiser PF. An Intravaginal Ring for the Simultaneous Delivery of an HIV-1 Maturation Inhibitor and Reverse-Transcriptase Inhibitor for Prophylaxis of HIV Transmission. J Pharm Sci 2015; 104:3426-39. [PMID: 26149293 DOI: 10.1002/jps.24551] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 12/17/2022]
Abstract
Nucleocapsid 7 (NCp7) inhibitors have been investigated extensively for their role in impeding the function of HIV-1 replication machinery and their ability to directly inactivate the virus. A class of NCp7 zinc finger inhibitors, S-acyl-2-mercaptobenzamide thioesters (SAMTs), was investigated for topical drug delivery. SAMTs are inherently unstable because of their hydrolytically labile thioester bond, thus requiring formulation approaches that can lend stability. We describe the delivery of N-[2-(3,4,5-trimethoxybenzoylthio)benzoyl]-β-alaninamide (SAMT-10), as a single agent antiretroviral (ARV) therapeutic and in combination with the HIV-1 reverse-transcriptase inhibitor pyrimidinedione IQP-0528, from a hydrophobic polyether urethane (PEU) intravaginal ring (IVR) for a month. The physicochemical stability of the ARV-loaded IVRs was confirmed after 3 months at 40°C/75% relative humidity. In vitro, 25 ± 3 mg/IVR of SAMT-10 and 86 ± 13 mg/IVR of IQP-0528 were released. No degradation of the hydrolytically labile SAMT-10 was observed within the matrix. The combination of ARVs had synergistic antiviral activity when tested in in vitro cell-based assays. Toxicological evaluations performed on an organotypic EpiVaginal(™) tissue model demonstrated a lack of formulation toxicity. Overall, SAMT-10 and IQP-0528 were formulated in a stable PEU IVR for sustained release. Our findings support the need for further preclinical evaluation. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3426-3439, 2015.
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Affiliation(s)
- Shweta R Ugaonkar
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112
| | - Justin T Clark
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208
| | - Lexie B English
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112
| | - Todd J Johnson
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112
| | | | - Robert J Bahde
- Laboratory of Bioorganic Chemistry, NIDDK, NIH, Bethesda, Maryland, 20892
| | - Daniel H Appella
- Laboratory of Bioorganic Chemistry, NIDDK, NIH, Bethesda, Maryland, 20892
| | | | - Patrick F Kiser
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, 60208
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Henning TR, McNicholl JM, Vishwanathan SA, Kersh EN. Macaque models of enhanced susceptibility to HIV. Virol J 2015; 12:90. [PMID: 26070461 PMCID: PMC4479314 DOI: 10.1186/s12985-015-0320-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 06/03/2015] [Indexed: 01/26/2023] Open
Abstract
There are few nonhuman primate models of enhanced HIV susceptibility. Such models can improve comprehension of HIV acquisition risk factors and provide rigorous testing platforms for preclinical prevention strategies. This paper reviews past, current, and proposed research on macaque HIV acquisition risk models and identifies areas where modeling is significantly lacking. We compare different experimental approaches and provide practical considerations for designing macaque susceptibility studies. Modifiable (mucosal and systemic coinfections, hormonal contraception, and rectal lubricants) and non-modifiable (hormonal fluctuations) risk factors are highlighted. Risk acquisition models via vaginal, rectal, and penile challenge routes are discussed. There is no consensus on the best statistical model for evaluating increased susceptibility, and additional research is required. The use of enhanced susceptibility macaque models would benefit multiple facets of the HIV research field, including basic acquisition and pathogenesis studies as well as the vaccine and other biomedical preventions pipeline.
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Affiliation(s)
- Tara R Henning
- Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS A-25, Atlanta, GA, 30333, USA.
| | - Janet M McNicholl
- Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS A-25, Atlanta, GA, 30333, USA.
| | - Sundaram A Vishwanathan
- Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS A-25, Atlanta, GA, 30333, USA.
| | - Ellen N Kersh
- Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS A-25, Atlanta, GA, 30333, USA.
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Dobard CW, Taylor A, Sharma S, Anderson PL, Bushman LR, Chuong D, Pau CP, Hanson D, Wang L, Garcia-Lerma JG, McGowan I, Rohan L, Heneine W. Protection Against Rectal Chimeric Simian/Human Immunodeficiency Virus Transmission in Macaques by Rectal-Specific Gel Formulations of Maraviroc and Tenofovir. J Infect Dis 2015; 212:1988-95. [PMID: 26071566 DOI: 10.1093/infdis/jiv334] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/29/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Rectal human immunodeficiency virus (HIV) transmission is an important driver of the HIV epidemic. Optimally formulated gels of antiretroviral drugs are under development for preventing rectally acquired HIV. We investigated in a macaque model the pharmacokinetics and efficacy of 3 rectal gel formulations METHODS Single-dose pharmacokinetics of low-osmolar 1% maraviroc (MVC), 1% tenofovir (TFV), or 1% MVC/1% TFV combination gel were evaluated in blood, rectal fluids, colorectal biopsy specimens, and rectal lymphocytes. Efficacy was evaluated over 10 twice-weekly rectal SHIV162p3 challenges in rhesus macaques that received either placebo (n = 7), MVC (n = 6), TFV (n = 6), or MVC/TFV (n = 6) gel 30 minutes before each challenge. RESULTS MVC and TFV were detected in plasma 30 minutes after gel application and remained above 95% inhibitory concentrations in rectal fluids at 24 hours. MVC, TFV, and TFV diphosphate (TFV-DP) concentrations in colorectal tissues collected up to 30 cm from the anal margin were all high at 2 hours, demonstrating rapid and extended tissue dosing. TFV-DP concentrations in tissue homogenates and rectal lymphocytes were highly correlated (r(2) = 0.82). All 3 gel formulations were highly protective (82% efficacy; P ≤ .02 by the log-rank test). CONCLUSIONS Desirable pharmacokinetic profiles and high efficacy in this macaque model support the clinical development of these gel formulations for preventing rectal HIV infection.
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Affiliation(s)
- Charles W Dobard
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Sunita Sharma
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Peter L Anderson
- Department of Pharmaceutical Sciences, University of Colorado School of Pharmacy, Aurora
| | - Lane R Bushman
- Department of Pharmaceutical Sciences, University of Colorado School of Pharmacy, Aurora
| | - Dinh Chuong
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Chou-Pong Pau
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Debra Hanson
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Lin Wang
- Magee Women's Research Institute, University of Pittsburgh, Pennsylvania
| | - J Gerardo Garcia-Lerma
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Ian McGowan
- Magee Women's Research Institute, University of Pittsburgh, Pennsylvania
| | - Lisa Rohan
- Magee Women's Research Institute, University of Pittsburgh, Pennsylvania
| | - Walid Heneine
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia
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Morris M, Aubert RD, Butler K, Henning T, Mitchell J, Jenkins L, Garber D, McNicholl J, Kersh EN. Preclinical evaluation of the immunomodulatory lymphocyte trafficking drug FTY720 for HIV prevention in the female genital mucosa of macaques. J Med Primatol 2015; 43:370-3. [PMID: 25379595 DOI: 10.1111/jmp.12120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
FTY720 has been shown to reduce inflammatory cytokines and immune cells in the genital mucosa of macaques. This pilot study examined the ability of FTY720 to inhibit HIV acquisition. Systemic treatment with FTY720 failed to prevent or delay vaginal SHIV transmission.
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MIV-150/zinc acetate gel inhibits cell-associated simian-human immunodeficiency virus reverse transcriptase infection in a macaque vaginal explant model. Antimicrob Agents Chemother 2015; 59:3829-37. [PMID: 25870063 DOI: 10.1128/aac.00073-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 04/07/2015] [Indexed: 12/22/2022] Open
Abstract
The transmission of both cell-free and cell-associated immunodeficiency viruses has been demonstrated directly in multiple animal species and possibly occurs in humans, as suggested by genotyping of the infecting human immunodeficiency virus (HIV) in acutely infected women and in semen from their partners. Therefore, a microbicide may need to block both mechanisms of HIV transmission to achieve maximum efficacy. To date, most of the preclinical evaluation of candidate microbicides has been performed using cell-free HIV. New models of mucosal transmission of cell-associated HIV are needed to evaluate candidate microbicide performance. The MIV-150/zinc acetate/carrageenan (MZC) gel protects Depo-Provera-treated macaques against cell-free simian-human immunodeficiency virus reverse transcriptase (SHIV-RT) infection when applied vaginally up to 8 h before challenge. We recently demonstrated the potent activity of MZC gel against cell-free SHIV-RT in macaque vaginal explants. In the current study, we established a cell-associated SHIV-RT infection model of macaque vaginal tissues and tested the activity of MZC gel in this model. MZC gel protected tissues against cell-associated SHIV-RT infection when present at the time of viral exposure or when applied up to 4 days prior to viral challenge. These data support clinical testing of the MZC gel. Overall, our ex vivo model of cell-associated SHIV-RT infection in macaque vaginal mucosa complements the cell-free infection models, providing tools for prioritization of products that block both modes of HIV transmission.
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Evaluation of Rapidly Disintegrating Vaginal Tablets of Tenofovir, Emtricitabine and Their Combination for HIV-1 Prevention. Pharmaceutics 2014; 6:616-631. [PMID: 25494201 PMCID: PMC4279136 DOI: 10.3390/pharmaceutics6040616] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 11/18/2014] [Accepted: 11/18/2014] [Indexed: 11/24/2022] Open
Abstract
Vaginal tablets are being developed as an alternative to gels as an inexpensive, discreet dosage form for the administration of microbicides. This work describes the pharmacokinetic (PK) evaluation of rapidly disintegrating vaginal tablets containing tenofovir (TFV, 10 mg), emtricitabine (FTC, 10 mg), and the combination of TFV and FTC (10 mg each) under in vitro and in vivo conditions, and in direct comparison to the clinical TFV 1% gel, a microbicide product in Phase III clinical testing. The PK of TFV and FTC from tablets were also evaluated in female rabbits following intravaginal administration. Direct comparison of a single dose of TFV tablets (intact or predissolved at 10 mg/mL) and TFV 1% gel showed no differences in the vaginal PK of TFV between groups; however systemic bioavailability of TFV was significantly higher from the gel. When rabbits were dosed either once or daily for seven days with intact tablets of TFV, FTC, or the combination of TFV/FTC, vaginal and systemic concentrations of TFV and FTC were unaffected by co-formulation. Moreover, plasma PK parameters were similar following a single dose or seven once-daily doses. Tissue concentrations of TFV and FTC in the cranial vagina 4 h after administration ranged between 104 and 105 ng/g. Concentrations of TFV-diphospate (TFV-DP, the active metabolite) were also high (over 103 ng/g or about 3000 to 6000 fmol/mg) in the cranial vagina 4 h after administration and similar to those measured following administration of TFV 1% gel. These data demonstrate that rapidly disintegrating vaginal tablets may be a suitable topical microbicide dosage form providing similar vaginal TFV PK to that of TFV 1% gel. The data also support co-administration of FTC with TFV in a single vaginal tablet to create a combination microbicide in a simple and inexpensive dosage form.
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57
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Pereira LE, Makarova N, Dobard C, Aubert RD, Srinivasan P, McNicholl J, Smith JM. Development and optimization of a non-enzymatic method of leukocyte isolation from macaque tissues. J Med Primatol 2014; 43:360-3. [PMID: 25379593 DOI: 10.1111/jmp.12121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND METHODS Cell isolation from macaque tissues involves laborious enzymatic digestion. The Medimachine provides a simpler, quicker non-enzymatic method, yielding 1.5–5 million cells/g of vaginal or rectal tissue from pigtailed macaques. RESULTS AND CONCLUSIONS Flow cytometry analysis of the two methods revealed similar levels of cell viability and most major cell lineage and activation markers.
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58
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Dobard C, Sharma S, Parikh UM, West R, Taylor A, Martin A, Pau CP, Hanson DL, Lipscomb J, Smith J, Novembre F, Hazuda D, Garcia-Lerma JG, Heneine W. Postexposure protection of macaques from vaginal SHIV infection by topical integrase inhibitors. Sci Transl Med 2014; 6:227ra35. [PMID: 24622515 DOI: 10.1126/scitranslmed.3007701] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Coitally delivered microbicide gels containing antiretroviral drugs are important for HIV prevention. However, to date, microbicides have contained entry or reverse transcriptase inhibitors that block early steps in virus infection and thus need to be given as a preexposure dose that interferes with sexual practices and may limit compliance. Integrase inhibitors block late steps after virus infection and therefore are more suitable for post-coital dosing. We first determined the kinetics of strand transfer in vitro and confirmed that integration begins about 6 hours after infection. We then used a repeat-challenge macaque model to assess efficacy of vaginal gels containing integrase strand transfer inhibitors when applied before or after simian/human immunodeficiency virus (SHIV) challenge. We showed that gel containing the strand transfer inhibitor L-870812 protected two of three macaques when applied 30 min before SHIV challenge. We next evaluated the efficacy of 1% raltegravir gel and demonstrated its ability to protect macaques when applied 3 hours after SHIV exposure (five of six protected; P < 0.05, Fisher's exact test). Breakthrough infections showed no evidence of drug resistance in plasma or vaginal secretions despite continued gel dosing after infection. We documented rapid vaginal absorption reflecting a short pharmacological lag time and noted that vaginal, but not plasma, virus load was substantially reduced in the breakthrough infection after raltegravir gel treatment. We provide a proof of concept that topically applied integrase inhibitors protect against vaginal SHIV infection when administered shortly before or 3 hours after virus exposure.
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Affiliation(s)
- Charles Dobard
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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Phillips KA, Bales KL, Capitanio JP, Conley A, Czoty PW, ‘t Hart BA, Hopkins WD, Hu SL, Miller LA, Nader MA, Nathanielsz PW, Rogers J, Shively CA, Voytko ML. Why primate models matter. Am J Primatol 2014; 76:801-27. [PMID: 24723482 PMCID: PMC4145602 DOI: 10.1002/ajp.22281] [Citation(s) in RCA: 391] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/01/2014] [Accepted: 03/02/2014] [Indexed: 12/13/2022]
Abstract
Research involving nonhuman primates (NHPs) has played a vital role in many of the medical and scientific advances of the past century. NHPs are used because of their similarity to humans in physiology, neuroanatomy, reproduction, development, cognition, and social complexity-yet it is these very similarities that make the use of NHPs in biomedical research a considered decision. As primate researchers, we feel an obligation and responsibility to present the facts concerning why primates are used in various areas of biomedical research. Recent decisions in the United States, including the phasing out of chimpanzees in research by the National Institutes of Health and the pending closure of the New England Primate Research Center, illustrate to us the critical importance of conveying why continued research with primates is needed. Here, we review key areas in biomedicine where primate models have been, and continue to be, essential for advancing fundamental knowledge in biomedical and biological research.
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Affiliation(s)
- Kimberley A. Phillips
- Department of Psychology, Trinity University, San Antonio TX 78212
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio TX
| | - Karen L. Bales
- Department of Psychology, University of California, Davis CA 95616
- California National Primate Research Center, Davis CA 95616
| | - John P. Capitanio
- Department of Psychology, University of California, Davis CA 95616
- California National Primate Research Center, Davis CA 95616
| | - Alan Conley
- Department of Population Health & Reproduction, School of Veterinary Medicine, University of California, Davis CA 95616
| | - Paul W. Czoty
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem NC 27157
| | - Bert A. ‘t Hart
- Department of Immunobiology, Biomedical Primate Research Center, Rijswick, The Netherlands
| | - William D. Hopkins
- Neuroscience Institute and Language Research Center, Georgia State University, Atlanta GA 30302
- Division of Cognitive and Developmental Neuroscience, Yerkes National Primate Research Center, Atlanta GA 30030
| | - Shiu-Lok Hu
- Department of Pharmaceutics and Washington National Primate Research Center, University of Washington, Seattle WA
| | - Lisa A. Miller
- California National Primate Research Center, Davis CA 95616
- Department of Anatomy, Physiology and Cell Biology, University of California, Davis CA 95616
| | - Michael A. Nader
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem NC 27157
| | - Peter W. Nathanielsz
- Center for Pregnancy and Newborn Research, University of Texas Health Science Center, San Antonio TX 78229
| | - Jeffrey Rogers
- Human Genome Sequencing Center, Baylor College of Medicine, Houston TX
- Wisconsin National Primate Research Center, Madison, WI
| | - Carol A. Shively
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem NC 27157
| | - Mary Lou Voytko
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem NC 27157
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Rollenhagen C, Lathrop MJ, Macura SL, Doncel GF, Asin SN. Herpes simplex virus type-2 stimulates HIV-1 replication in cervical tissues: implications for HIV-1 transmission and efficacy of anti-HIV-1 microbicides. Mucosal Immunol 2014; 7:1165-74. [PMID: 24496317 PMCID: PMC4137741 DOI: 10.1038/mi.2014.3] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 12/18/2013] [Accepted: 01/03/2014] [Indexed: 02/04/2023]
Abstract
Herpes Simplex virus Type-2 (HSV-2) increases the risk of HIV-1 acquisition, yet the mechanism for this viral pathogen to regulate the susceptibility of the cervicovaginal mucosa to HIV-1 is virtually unknown. Using ex vivo human ectocervical tissue models, we report greater levels of HIV-1 reverse transcription, DNA integration, RNA expression, and virions release in HIV-1/HSV-2 co-infected tissues compared with HIV-1 only infected tissues (P<0.05). Enhanced HIV-1 replication was associated with increased CD4, CCR5, and CD38 transcription (P<0.05) and increased number of CD4(+)/CCR5(+)/CD38(+) T cells in HIV-1/HSV-2 co-infected tissues compared with tissues infected with HIV-1 alone. Tenofovir (TFV) 1% gel, the leading microbicide candidate, demonstrated only partial protection against HIV-1, when applied vaginally before and after sexual intercourse. It is possible that mucosal inflammation, in particular that induced by HSV-2 infection, may have decreased TFV efficacy. HSV-2 upregulated the number of HIV-1-infected cells and elevated the concentration of TFV needed to decrease HIV-1 infection. Similarly, only high concentrations of TFV inhibited HSV-2 replication in HIV-1/HSV-2-infected tissues. Thus, HSV-2 co-infection and mucosal immune cell activation should be taken into consideration when designing preventative strategies for sexual transmission of HIV-1.
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Affiliation(s)
- C Rollenhagen
- V.A. Medical Center, White River Junction, Vermont, USA,Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, New Hampshire, USA
| | - M J Lathrop
- Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, New Hampshire, USA
| | - S L Macura
- V.A. Medical Center, White River Junction, Vermont, USA
| | - G F Doncel
- CONRAD, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - S N Asin
- V.A. Medical Center, White River Junction, Vermont, USA,Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, New Hampshire, USA,
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Pharmacokinetics and preliminary safety study of pod-intravaginal rings delivering antiretroviral combinations for HIV prophylaxis in a macaque model. Antimicrob Agents Chemother 2014; 58:5125-35. [PMID: 24936594 DOI: 10.1128/aac.02871-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Preexposure prophylaxis using oral regimens involving the HIV nucleoside reverse transcriptase inhibitors tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) demonstrated efficacy in three clinical trials. Adherence was determined to be a key parameter for success. Incorporation of the TDF-FTC combination into intravaginal rings (IVRs) for sustained mucosal delivery could increase product adherence and efficacy compared with those of oral and vaginal gel formulations. A novel pod-IVR technology capable of delivering multiple drugs is described; this constitutes the first report of an IVR delivering TDF and FTC, as well as a triple-combination IVR delivering TDF, FTC, and the entry inhibitor maraviroc (MVC). The pharmacokinetics and preliminary local safety of the two combination pod-IVRs were evaluated in the pig-tailed macaque model. The devices exhibited sustained release at controlled rates over the 28-day study period. Median steady-state drug levels in vaginal tissues in the TDF-FTC group were 30 μg g(-1) (tenofovir [TFV], in vivo hydrolysis product of TDF) and 500 μg g(-1) (FTC) and in the TDF-FTC-MVC group were 10 μg g(-1) (TFV), 150 μg g(-1) (FTC), and 20 μg g(-1) (MVC). No adverse events were observed, and there were no toxicological findings. Mild-to-moderate increases in inflammatory infiltrates were observed in the vaginal tissues of some animals in both the presence and the absence of the IVRs. The IVRs did not disturb the vaginal microbiota, and levels of proinflammatory cytokines remained stable throughout the study. Pod-IVR candidates based on the TDF-FTC combination have potential for the prevention of vaginal HIV acquisition and merit clinical investigation.
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Anderson PL, Glidden DV, Bushman LR, Heneine W, García-Lerma JG. Tenofovir diphosphate concentrations and prophylactic effect in a macaque model of rectal simian HIV transmission. J Antimicrob Chemother 2014; 69:2470-6. [PMID: 24862094 DOI: 10.1093/jac/dku162] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES This study evaluated the relationship between intracellular tenofovir diphosphate concentrations in peripheral blood mononuclear cells and prophylactic efficacy in a macaque model for HIV pre-exposure prophylaxis (PrEP). METHODS Macaques were challenged with simian HIV (SHIV) via rectal inoculation once weekly for up to 14 weeks. A control group (n=34) received no drug, a second group (n=6) received oral tenofovir disoproxil fumarate/emtricitabine 3 days before each virus challenge and a third group (n=6) received the same dosing plus another dose 2 h after virus challenge. PBMCs were collected just before each weekly virus challenge. The relationship between tenofovir diphosphate in PBMCs and prophylactic efficacy was assessed with a Cox proportional hazards model. RESULTS The percentages of animals infected in the control, one-dose and two-dose groups were 97, 83 and 17, respectively. The mean (SD) steady-state tenofovir diphosphate concentration (fmol/10(6) cells) was 15.8 (7.6) in the one-dose group and 30.7 (10.1) in the two-dose group. Each 5 fmol tenofovir diphosphate/10(6) cells was associated with a 40% (95% CI 17%-56%) reduction in risk of SHIV acquisition, P=0.002. The tenofovir diphosphate concentration associated with a 90% reduction in risk (EC90) was 22.6 fmol/10(6) cells (95% CI 13.8-60.8). CONCLUSIONS The prophylactic EC90 for tenofovir diphosphate identified in macaques exposed rectally compares well with the EC90 previously identified in men who have sex with men (MSM; 16 fmol/10(6) cells, 95% CI 3-28). These results highlight the relevance of this model to inform human PrEP studies of oral tenofovir disoproxil fumarate/emtricitabine for MSM.
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Affiliation(s)
- Peter L Anderson
- The Department of Pharmaceutical Sciences, University of Colorado Denver, 12850 E. Montview Blvd, Aurora, CO 80045, USA
| | - David V Glidden
- The Department of Epidemiology and Biostatistics, University of California San Francisco, 185 Berry St W., San Francisco, CA 94143, USA
| | - Lane R Bushman
- The Department of Pharmaceutical Sciences, University of Colorado Denver, 12850 E. Montview Blvd, Aurora, CO 80045, USA
| | - Walid Heneine
- The Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control, 1600 Clifton Rd, Atlanta, GA 30329, USA
| | - J Gerardo García-Lerma
- The Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control, 1600 Clifton Rd, Atlanta, GA 30329, USA
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63
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Henning TR, Butler K, Hanson D, Sturdevant G, Ellis S, Sweeney EM, Mitchell J, Deyounks F, Phillips C, Farshy C, Fakile Y, Papp J, Evan Secor W, Caldwell H, Patton D, McNicholl JM, Kersh E. Increased susceptibility to vaginal simian/human immunodeficiency virus transmission in pig-tailed macaques coinfected with Chlamydia trachomatis and Trichomonas vaginalis. J Infect Dis 2014; 210:1239-47. [PMID: 24755433 DOI: 10.1093/infdis/jiu240] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Sexually transmitted infections (STIs) are associated with an increased risk of human immunodeficiency virus (HIV) infection, but their biological effect on HIV susceptibility is not fully understood. METHODS Female pig-tailed macaques inoculated with Chlamydia trachomatis and Trichomonas vaginalis (n = 9) or medium (controls; n = 7) were repeatedly challenged intravaginally with SHIVSF162p3. Virus levels were evaluated by real-time polymerase chain reaction, plasma and genital cytokine levels by Luminex assays, and STI clinical signs by colposcopy. RESULTS Simian/HIV (SHIV) susceptibility was enhanced in STI-positive macaques (P = .04, by the log-rank test; relative risk, 2.5 [95% confidence interval, 1.1-5.6]). All STI-positive macaques were SHIV infected, whereas 3 controls (43%) remained uninfected. Moreover, relative to STI-negative animals, SHIV infections occurred earlier in the menstrual cycle in STI-positive macaques (P = .01, by the Wilcoxon test). Levels of inflammatory cytokines (interferon γ, interleukin 6, and granulocyte colony-stimulating factor [G-CSF]) were higher in STI-positive macaques during STI inoculation and SHIV exposure periods (P ≤ .05, by the Wilcoxon test). CONCLUSIONS C. trachomatis and T. vaginalis infection increase the susceptibility to SHIV, likely because of prolonged genital tract inflammation. These novel data demonstrate a biological link between these nonulcerative STIs and the risk of SHIV infection, supporting epidemiological associations of HIV and STIs. This study establishes a macaque model for studies of high-risk HIV transmission and prevention.
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Affiliation(s)
| | | | | | - Gail Sturdevant
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | | | | | | | | | | | | | | | | | - W Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention
| | - Harlan Caldwell
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Dorothy Patton
- Department of Obstetrics and Gynecology, University of Washington, Seattle
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64
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McNicholl JM, Henning TC, Vishwanathan SA, Kersh EN. Non-human primate models of hormonal contraception and HIV. Am J Reprod Immunol 2014; 71:513-22. [PMID: 24716832 DOI: 10.1111/aji.12246] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 03/03/2014] [Indexed: 12/17/2022] Open
Abstract
PROBLEM Recent concerns that hormonal contraception (HC) may increase risk of HIV acquisition has led to keen interest in using non-human primates (NHP) to understand the underlying mechanism and the magnitude of the risk. This is, in part, because some experiments which would be difficult or logistically impossible in women are more easily conducted in NHP. METHOD OF STUDY NHP models of HIV can inform HIV acquisition and pathogenesis research and identify and evaluate biomedical preventions and treatments for HIV/AIDS. Widely used species include rhesus, pigtail, and cynomolgous macaques. RESULTS This paper reviews past, current and proposed NHP research around the intersection of HIV and HC. CONCLUSION NHP research may lead to the identification of hormonally regulated biomarkers that correlate with HIV-acquisition risk, to a ranking of existing or next-generation HC along an HIV-acquisition risk profile, and inform research around new biomedical preventions for HIV.
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Affiliation(s)
- Janet M McNicholl
- Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
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65
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Cottrell ML, Kashuba ADM. Topical microbicides and HIV prevention in the female genital tract. J Clin Pharmacol 2014; 54:603-15. [PMID: 24664786 DOI: 10.1002/jcph.292] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 03/19/2014] [Indexed: 11/05/2022]
Abstract
Worldwide, HIV disproportionately affects women who are often unable to negotiate traditional HIV preventive strategies such as condoms. In the absence of an effective vaccine or cure, chemoprophylaxis may be a valuable self-initiated alternative. Topical microbicides have been investigated as one such option. The first generation topical microbicides were non-specific, broad-spectrum antimicrobial agents, including surfactants, polyanions, and acid buffering gels, that generally exhibited contraceptive properties. After extensive clinical study, none prevented HIV infection, and their development was abandoned. Second generation topical microbicides include agents with selective mechanisms of antiviral activity. Most are currently being used for, or have previously been explored as, drugs for treatment of HIV. The most advanced of these is tenofovir 1% gel: the first topical agent shown to significantly reduce HIV infection by 39% compared to placebo. This review summarizes the evolution of topical microbicides for HIV chemoprophylaxis, highlights important concepts learned, and offers current and future considerations for this area of research.
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Affiliation(s)
- Mackenzie L Cottrell
- University of North Carolina at Chapel Hill, UNC Eshelman School of Pharmacy, Chapel Hill, NC, USA
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66
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Clark JT, Clark MR, Shelke NB, Johnson TJ, Smith EM, Andreasen AK, Nebeker JS, Fabian J, Friend DR, Kiser PF. Engineering a segmented dual-reservoir polyurethane intravaginal ring for simultaneous prevention of HIV transmission and unwanted pregnancy. PLoS One 2014; 9:e88509. [PMID: 24599325 PMCID: PMC3943718 DOI: 10.1371/journal.pone.0088509] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 01/07/2014] [Indexed: 11/06/2022] Open
Abstract
The HIV/AIDS pandemic and its impact on women prompt the investigation of prevention strategies to interrupt sexual transmission of HIV. Long-acting drug delivery systems that simultaneously protect womenfrom sexual transmission of HIV and unwanted pregnancy could be important tools in combating the pandemic. We describe the design, in silico, in vitro and in vivo evaluation of a dual-reservoir intravaginal ring that delivers the HIV-1 reverse transcriptase inhibitor tenofovir and the contraceptive levonorgestrel for 90 days. Two polyether urethanes with two different hard segment volume fractions were used to make coaxial extruded reservoir segments with a 100 µm thick rate controlling membrane and a diameter of 5.5 mm that contain 1.3 wt% levonorgestrel. A new mechanistic diffusion model accurately described the levonorgestrel burst release in early time points and pseudo-steady state behavior at later time points. As previously described, tenofovir was formulated as a glycerol paste and filled into a hydrophilic polyurethane, hollow tube reservoir that was melt-sealed by induction welding. These tenofovir-eluting segments and 2 cm long coaxially extruded levonorgestrel eluting segments were joined by induction welding to form rings that released an average of 7.5 mg tenofovir and 21 µg levonorgestrel per day in vitro for 90 days. Levonorgestrel segments placed intravaginally in rabbits resulted in sustained, dose-dependent levels of levonorgestrel in plasma and cervical tissue for 90 days. Polyurethane caps placed between segments successfully prevented diffusion of levonorgestrel into the tenofovir-releasing segment during storage.Hydrated rings endured between 152 N and 354 N tensile load before failure during uniaxial extension testing. In summary, this system represents a significant advance in vaginal drug delivery technology, and is the first in a new class of long-acting multipurpose prevention drug delivery systems.
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Affiliation(s)
- Justin T. Clark
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Meredith R. Clark
- CONRAD, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Arlington, Virginia, United States of America
| | - Namdev B. Shelke
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Todd J. Johnson
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Eric M. Smith
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Andrew K. Andreasen
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Joel S. Nebeker
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Judit Fabian
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - David R. Friend
- CONRAD, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Arlington, Virginia, United States of America
| | - Patrick F. Kiser
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biomedical Engineering, Northwestern University, Evanston IL, United States of America
- * E-mail:
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67
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Hsu M, Keele BF, Aravantinou M, Krawczyk N, Seidor S, Abraham CJ, Zhang S, Rodriguez A, Kizima L, Derby N, Jean-Pierre N, Mizenina O, Gettie A, Grasperge B, Blanchard J, Piatak MJ, Lifson JD, Fernández-Romero JA, Zydowsky TM, Robbiani M. Exposure to MIV-150 from a high-dose intravaginal ring results in limited emergence of drug resistance mutations in SHIV-RT infected rhesus macaques. PLoS One 2014; 9:e89300. [PMID: 24586674 PMCID: PMC3937329 DOI: 10.1371/journal.pone.0089300] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 01/17/2014] [Indexed: 11/19/2022] Open
Abstract
When microbicides used for HIV prevention contain antiretroviral drugs, there is concern for the potential emergence of drug-resistant HIV following use in infected individuals who are either unaware of their HIV infection status or who are aware but still choose to use the microbicide. Resistant virus could ultimately impact their responsiveness to treatment and/or result in subsequent transmission of drug-resistant virus. We tested whether drug resistance mutations (DRMs) would emerge in macaques infected with simian immunodeficiency virus expressing HIV reverse transcriptase (SHIV-RT) after sustained exposure to the potent non-nucleoside reverse transcriptase inhibitor (NNRTI) MIV-150 delivered via an intravaginal ring (IVR). We first treated 4 SHIV-RT-infected animals with daily intramuscular injections of MIV-150 over two 21 day (d) intervals separated by a 7 d drug hiatus. In all 4 animals, NNRTI DRMs (single and combinations) were detected within 14 d and expanded in proportion and diversity with time. Knowing that we could detect in vivo emergence of NNRTI DRMs in response to MIV-150, we then tested whether a high-dose MIV-150 IVR (loaded with >10 times the amount being used in a combination microbicide IVR in development) would select for resistance in 6 infected animals, modeling use of this prevention method by an HIV-infected woman. We previously demonstrated that this MIV-150 IVR provides significant protection against vaginal SHIV-RT challenge. Wearing the MIV-150 IVR for 56 d led to only 2 single DRMs in 2 of 6 animals (430 RT sequences analyzed total, 0.46%) from plasma and lymph nodes despite MIV-150 persisting in the plasma, vaginal fluids, and genital tissues. Only wild type virus sequences were detected in the genital tissues. These findings indicate a low probability for the emergence of DRMs after topical MIV-150 exposure and support the advancement of MIV-150-containing microbicides.
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Affiliation(s)
- Mayla Hsu
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Brandon F. Keele
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc. (formerly SAIC-Frederick, Inc.), Frederick National Laboratory, Frederick, Maryland, United States of America
| | - Meropi Aravantinou
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Noa Krawczyk
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Samantha Seidor
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Ciby J. Abraham
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Shimin Zhang
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Aixa Rodriguez
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Larisa Kizima
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Nina Derby
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Ninochka Jean-Pierre
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Olga Mizenina
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Agegnehu Gettie
- Aaron Diamond AIDS Research Center, Rockefeller University, New York, New York, United States of America
| | - Brooke Grasperge
- Tulane National Primate Research Center, Covington, Louisiana, United States of America
| | - James Blanchard
- Tulane National Primate Research Center, Covington, Louisiana, United States of America
| | - Michael J. Piatak
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc. (formerly SAIC-Frederick, Inc.), Frederick National Laboratory, Frederick, Maryland, United States of America
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc. (formerly SAIC-Frederick, Inc.), Frederick National Laboratory, Frederick, Maryland, United States of America
| | - José A. Fernández-Romero
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Thomas M. Zydowsky
- Center for Biomedical Research, Population Council, New York, New York, United States of America
| | - Melissa Robbiani
- Center for Biomedical Research, Population Council, New York, New York, United States of America
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Pharmacokinetic and safety analyses of tenofovir and tenofovir-emtricitabine vaginal tablets in pigtailed macaques. Antimicrob Agents Chemother 2014; 58:2665-74. [PMID: 24566178 DOI: 10.1128/aac.02336-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vaginal rapidly disintegrating tablets (RDTs) containing tenofovir (TFV) or TFV and emtricitabine (FTC) were evaluated for safety and pharmacokinetics in pigtailed macaques. Two separate animal groups (n = 4) received TFV (10 mg) or TFV-FTC (10 mg each) RDTs, administered near the cervix. A third group (n = 4) received 1 ml TFV gel. Blood plasma, vaginal tissue biopsy specimens, and vaginal fluids were collected before and after product application at 0, 0.5, 1, 4, and 24 h. A disintegration time of <30 min following vaginal application of the RDTs was noted, with negligible effects on local inflammatory cytokines, vaginal pH, and microflora. TFV pharmacokinetics were generally similar for both RDTs and gel, with peak median concentrations in vaginal tissues and vaginal secretions being on the order of 10(4) to 10(5) ng/g (147 to 571 μM) and 10(6) ng/g (12 to 34 mM), respectively, at 1 to 4 h postdose. At 24 h, however, TFV vaginal tissue levels were more sustained after RDT dosing, with median TFV concentrations being approximately 1 log higher than those with gel dosing. FTC pharmacokinetics after combination RDT dosing were similar to those of TFV, with peak median vaginal tissue and fluid levels being on the order of 10(4) ng/g (374 μM) and 10(6) ng/g (32 mM), respectively, at 1 h postdose with levels in fluid remaining high at 24 h. RDTs are a promising alternative vaginal dosage form, delivering TFV and/or FTC at levels that would be considered inhibitory to simian-human immunodeficiency virus in the macaque vaginal microenvironment over a 24-h period.
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69
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Biodistribution and pharmacokinetics of dapivirine-loaded nanoparticles after vaginal delivery in mice. Pharm Res 2014; 31:1834-45. [PMID: 24449442 DOI: 10.1007/s11095-013-1287-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 12/31/2013] [Indexed: 10/25/2022]
Abstract
PURPOSE To assess the potential of polymeric nanoparticles (NPs) to affect the genital distribution and local and systemic pharmacokinetics (PK) of the anti-HIV microbicide drug candidate dapivirine after vaginal delivery. METHODS Dapivirine-loaded, poly(ethylene oxide)-coated poly(epsilon-caprolactone) (PEO-PCL) NPs were prepared by a nanoprecipitation method. Genital distribution of NPs and their ability to modify the PK of dapivirine up to 24 h was assessed after vaginal instillation in a female mouse model. Also, the safety of NPs upon daily administration for 14 days was assessed by histological analysis and chemokine/cytokine content in vaginal lavages. RESULTS PEO-PCL NPs (180-200 nm) were rapidly eliminated after administration but able to distribute throughout the vagina and lower uterus, and capable of tackling mucus and penetrate the epithelial lining. Nanocarriers modified the PK of dapivirine, with higher drug levels being recovered from vaginal lavages and vaginal/lower uterine tissues as compared to a drug suspension. Systemic drug exposure was reduced when NPs were used. Also, NPs were shown safe upon administration for 14 days. CONCLUSIONS Dapivirine-loaded PEO-PCL NPs were able to provide likely favorable genital drug levels, thus attesting the potential value of using this vaginal drug delivery nanosystem in the context of HIV prophylaxis.
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70
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Wei X, Hunt G, Abdool Karim SS, Naranbhai V, Sibeko S, Abdool Karim Q, Li JF, Kashuba ADM, Werner L, Passmore JAS, Morris L, Heneine W, Johnson JA. Sensitive tenofovir resistance screening of HIV-1 from the genital and blood compartments of women with breakthrough infections in the CAPRISA 004 tenofovir gel trial. J Infect Dis 2014; 209:1916-20. [PMID: 24436453 DOI: 10.1093/infdis/jiu026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The Centre for the AIDS Programme of Research in South Africa 004 (CAPRISA 004) study demonstrated that vaginally applied tenofovir gel is a promising intervention for protecting women from sexually acquiring human immunodeficiency virus (HIV). However, the potential for emergence of tenofovir resistance remains a concern in women who seroconvert while using the gel despite the lack of plasma virus resistance as assessed by population sequencing during the trial. We applied highly sensitive polymerase chain reaction-based assays to screen for tenofovir resistance in plasma and vaginal swab specimens. The absence of mutation detection suggested little immediate risk of tenofovir-resistant HIV-1 emergence and forward transmission in settings in which gel users are closely monitored for HIV seroconversion.
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Affiliation(s)
- Xierong Wei
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Salim S Abdool Karim
- Department of Epidemiology, Columbia University, New York, New York CAPRISA-Centre for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban
| | - Vivek Naranbhai
- CAPRISA-Centre for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban
| | - Sengeziwe Sibeko
- CAPRISA-Centre for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban
| | - Quarraisha Abdool Karim
- Department of Epidemiology, Columbia University, New York, New York CAPRISA-Centre for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban
| | - Jin-Fen Li
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Lise Werner
- CAPRISA-Centre for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban
| | - Jo-Ann S Passmore
- National Health Laboratory Service, Johannesburg CAPRISA-Centre for the AIDS Programme of Research in South Africa, University of KwaZulu-Natal, Durban
| | - Lynn Morris
- National Institute for Communicable Diseases
| | - Walid Heneine
- Centers for Disease Control and Prevention, Atlanta, Georgia
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Abstract
PURPOSE OF REVIEW Early studies have cast doubt on the utility of animal models for predicting success or failure of HIV-prevention strategies, but results of multiple human phase 3 microbicide trials, and interrogations into the discrepancies between human and animal model trials, indicate that animal models were, and are, predictive of safety and efficacy of microbicide candidates. RECENT FINDINGS Recent studies have shown that topically applied vaginal gels, and oral prophylaxis using single or combination antiretrovirals are indeed effective in preventing sexual HIV transmission in humans, and all of these successes were predicted in animal models. Further, prior discrepancies between animal and human results are finally being deciphered as inadequacies in study design in the model, or quite often, noncompliance in human trials, the latter being increasingly recognized as a major problem in human microbicide trials. SUMMARY Successful microbicide studies in humans have validated results in animal models, and several ongoing studies are further investigating questions of tissue distribution, duration of efficacy, and continued safety with repeated application of these, and other promising microbicide candidates in both murine and nonhuman primate models. Now that we finally have positive correlations with prevention strategies and protection from HIV transmission, we can retrospectively validate animal models for their ability to predict these results, and more importantly, prospectively use these models to select and advance even safer, more effective, and importantly, more durable microbicide candidates into human trials.
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Abstract
HIV pre-exposure prophylaxis (PrEP) with daily oral tenofovir disoproxil fumarate (TDF) or TDF–emtricitabine (FTC) has been shown to be effective against sexual and injection-drug related HIV acquisition in four out of six large clinical trials. This article reviews the pharmacology of TDF and FTC as it relates both to PrEP efficacy and the emergence of viral resistance, summarizes the six trials and the inherent challenges to PrEP they highlighted, and proposes some future areas for further exploration.
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Affiliation(s)
- Lynn A Paxton
- Division of HIV/AIDS Prevention, Centers for Disease Control & Prevention, Atlanta, GA, USA and USAID, 686 Old Bagamoyo Road, Msasani, PO Box 9130, Dar es Salaam, Tanzania
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Romano J, Kashuba A, Becker S, Cummins J, Turpin J, Veronese, on Behalf of the Antiretr F. Pharmacokinetics and pharmacodynamics in HIV prevention; current status and future directions: a summary of the DAIDS and BMGF sponsored think tank on pharmacokinetics (PK)/pharmacodynamics (PD) in HIV prevention. AIDS Res Hum Retroviruses 2013; 29:1418-27. [PMID: 23614610 DOI: 10.1089/aid.2013.0122] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Thirty years after its beginning, the HIV/AIDS epidemic is still raging around the world. According to UNAIDS, in 2011 alone 1.7M deaths were attributable to AIDS, and 2.5M people were newly infected by the virus. Despite the success in treating HIV-infected people with potent antiretroviral drugs, preventing HIV infection is the key to ending the epidemic. Recently, the efficacy of topical and systemic antiviral chemoprophylaxis (i.e., preexposure prophylaxis or "PrEP"), using the same drugs used for HIV treatment, has been demonstrated in a number of clinical trials. However, results from other trials have been inconsistent, especially those evaluating PrEP in women. These inconsistencies may result from our incomplete understanding of pharmacokinetics (PK)/pharmacodynamics (PD) at the mucosal sites of sexual transmission: the male and female gastrointestinal and reproductive tracts. The drug concentrations used in these trials were derived from those used for treatment; however, we still do not know the relationship between the therapeutic and the preventive dose. This article presents the first comprehensive review of the available data in the HIV pharmacology field from animal models to human studies, and outlines gaps, challenges, and future directions. Addressing these pharmacological gaps and challenges will be critical in selecting and advancing future PrEP candidates and strategies with the greatest impact on the HIV epidemic.
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Affiliation(s)
| | - Angela Kashuba
- University of North Carolina (UNC) at Chapel Hill, Chapel Hill, North Carolina
| | - Stephen Becker
- Bill and Melinda Gates Foundation (BMGF), Seattle, Washington
| | - James Cummins
- Prevention Sciences Program (PSP), Division of AIDS (DAIDS), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - Jim Turpin
- Prevention Sciences Program (PSP), Division of AIDS (DAIDS), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - Fulvia Veronese, on Behalf of the Antiretr
- Prevention Sciences Program (PSP), Division of AIDS (DAIDS), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
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Effect of tenofovir on nucleotidases and cytokines in HIV-1 target cells. PLoS One 2013; 8:e78814. [PMID: 24205323 PMCID: PMC3808279 DOI: 10.1371/journal.pone.0078814] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/17/2013] [Indexed: 01/01/2023] Open
Abstract
Tenofovir (TFV) has been widely used for pre-exposure prophylaxis of HIV-1 infection with mixed results. While the use of TFV in uninfected individuals for prevention of HIV-1 acquisition is actively being investigated, the possible consequences of TFV exposure for the HIV-target cells and the mucosal microenvironment are unknown. In the current study, we evaluated the effects of TFV treatment on blood-derived CD4⁺ T cells, monocyte-derived macrophages and dendritic cells (DC). Purified HIV-target cells were treated with different concentrations of TFV (0.001-1.0 mg/ml) for 2 to 24 hr. RNA was isolated and RT-PCR was performed to compare the levels of mRNA expression of nucleotidases and pro-inflammatory cytokine genes (MIP3α, IL-8 and TNFα) in the presence or absence of TFV. We found that TFV increases 5'-ecto-nucleotidase (NT5E) and inhibits mitochondrial nucleotidase (NT5M) gene expression and increases 5' nucleotidase activity in macrophages. We also observed that TFV stimulates the expression and secretion of IL-8 by macrophages, DC, and activated CD4⁺ T cells and increases the expression and secretion of MIP3α by macrophages. In contrast, TFV had no effect on TNFα secretion from macrophages, DC and CD4⁺ T cells. Our results demonstrate that TFV alters innate immune responses in HIV-target cells with potential implications for increased inflammation at mucosal surfaces. As new preventive trials are designed, these findings should provide a foundation for understanding the effects of TFV on HIV-target cells in microbicide trials.
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Gupta SK, Nutan. Clinical use of vaginal or rectally applied microbicides in patients suffering from HIV/AIDS. HIV AIDS-RESEARCH AND PALLIATIVE CARE 2013; 5:295-307. [PMID: 24174883 PMCID: PMC3808211 DOI: 10.2147/hiv.s39164] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Microbicides, primarily used as topical pre-exposure prophylaxis, have been proposed to prevent sexual transmission of HIV. This review covers the trends and challenges in the development of safe and effective microbicides to prevent sexual transmission of HIV Initial phases of microbicide development used such surfactants as nonoxynol-9 (N-9), C13G, and sodium lauryl sulfate, aiming to inactivate the virus. Clinical trials of microbicides based on N-9 and C31G failed to inhibit sexual transmission of HIV. On the contrary, N-9 enhanced susceptibility to sexual transmission of HIV-1. Subsequently, microbicides based on polyanions and a variety of other compounds that inhibit the binding, fusion, or entry of virus to the host cells were evaluated for their efficacy in different clinical setups. Most of these trials failed to show either safety or efficacy for prevention of HIV transmission. The next phase of microbicide development involved antiretroviral drugs. Microbicide in the form of 1% tenofovir vaginal gel when tested in a Phase IIb trial (CAPRISA 004) in a coitally dependent manner revealed that tenofovir gel users were 39% less likely to become HIV-infected compared to placebo control. However, in another trial (VOICE MTN 003), tenofovir gel used once daily in a coitally independent mode failed to show any efficacy to prevent HIV infection. Tenofovir gel is currently in a Phase III safety and efficacy trial in South Africa (FACTS 001) employing a coitally dependent dosing regimen. Further, long-acting microbicide-delivery systems (vaginal ring) for slow release of such antiretroviral drugs as dapivirine are also undergoing clinical trials. Discovering new markers as correlates of protective efficacy, novel long-acting delivery systems with improved adherence in the use of microbicides, discovering new compounds effective against a broad spectrum of HIV strains, developing multipurpose technologies incorporating additional features of efficacy against other sexually transmitted infections, and contraception will help in moving the field of microbicide development forward.
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Affiliation(s)
- Satish Kumar Gupta
- Reproductive Cell Biology Laboratory, National Institute of Immunology, New Delhi, India
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Thurman AR, Clark MR, Hurlburt JA, Doncel GF. Intravaginal rings as delivery systems for microbicides and multipurpose prevention technologies. Int J Womens Health 2013; 5:695-708. [PMID: 24174884 PMCID: PMC3808127 DOI: 10.2147/ijwh.s34030] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
There is a renewed interest in delivering pharmaceutical products via intravaginal rings (IVRs). IVRs are flexible torus-shaped drug delivery systems that can be easily inserted and removed by the woman and that provide both sustained and controlled drug release, lasting for several weeks to several months. In terms of women's health care products, it has been established that IVRs effectively deliver contraceptive steroids and steroids for the treatment of postmenopausal vaginal atrophy. A novel application for IVRs is the delivery of antiretroviral drugs for the prevention of human immunodeficiency virus (HIV) genital infection. Microbicides are antiviral drugs delivered topically for HIV prevention. Recent reviews of microbicide IVRs have focused on technologies in development and optimizing ring design. IVRs have several advantages, including the ability to deliver sustained drug doses for long periods of time while bypassing first pass metabolism in the gut. IVRs are discreet, woman-controlled, and do not require a trained provider for placement or fitting. Previous data support that women and their male sexual partners find IVRs highly acceptable. Multipurpose prevention technology (MPT) products provide protection against unintended/mistimed pregnancy and reproductive tract infections, including HIV. Several MPT IVRs are currently in development. Early clinical testing of new microbicide and MPT IVRs will require a focus on safety, pharmacokinetics and pharmacodynamics. Specifically, IVRs will have to deliver tissue concentrations of drugs that are pharmacodynamically active, do not cause mucosal alterations or inflammation, and do not change the resident microbiota. The emergence of resistance to antiretrovirals will need to be investigated. IVRs should not disrupt intercourse or have high rates of expulsion. Herein, we reviewed the microbicide and MPT IVRs currently in development, with a focus on the clinical aspects of IVR assessment and the challenges facing microbicide and MPT IVR product development, clinical testing, and implementation. The information in this review was drawn from PubMed searches and a recent microbicide/MPT product development workshop organized by CONRAD.
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Affiliation(s)
- Andrea Ries Thurman
- CONRAD, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Meredith R Clark
- CONRAD, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Jennifer A Hurlburt
- CONRAD, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Gustavo F Doncel
- CONRAD, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA, USA
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Intravaginal ring eluting tenofovir disoproxil fumarate completely protects macaques from multiple vaginal simian-HIV challenges. Proc Natl Acad Sci U S A 2013; 110:16145-50. [PMID: 24043812 DOI: 10.1073/pnas.1311355110] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Topical preexposure prophylaxis interrupts HIV transmission at the site of mucosal exposure. Intermittently dosed vaginal gels containing the HIV-1 reverse transcriptase inhibitor tenofovir protected pigtailed macaques depending on the timing of viral challenge relative to gel application. However, modest or no protection was observed in clinical trials. Intravaginal rings (IVRs) may improve efficacy by providing long-term sustained drug delivery leading to constant mucosal antiretroviral concentrations and enhancing adherence. Although a few IVRs have entered the clinical pipeline, 100% efficacy in a repeated macaque vaginal challenge model has not been achieved. Here we describe a reservoir IVR technology that delivers the tenofovir prodrug tenofovir disoproxil fumarate (TDF) continuously over 28 d. With four monthly ring changes in this repeated challenge model, TDF IVRs generated reproducible and protective drug levels. All TDF IVR-treated macaques (n = 6) remained seronegative and simian-HIV RNA negative after 16 weekly vaginal exposures to 50 tissue culture infectious dose SHIV162p3. In contrast, 11/12 control macaques became infected, with a median of four exposures assuming an eclipse of 7 d from infection to virus RNA detection. Protection was associated with tenofovir levels in vaginal fluid [mean 1.8 × 10(5) ng/mL (range 1.1 × 10(4) to 6.6 × 10(5) ng/mL)] and ex vivo antiviral activity of cervicovaginal lavage samples. These observations support further advancement of TDF IVRs as well as the concept that extended duration drug delivery devices delivering topical antiretrovirals could be effective tools in preventing the sexual transmission of HIV in humans.
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78
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Friend DR, Kiser PF. Assessment of topical microbicides to prevent HIV-1 transmission: Concepts, testing, lessons learned. Antiviral Res 2013; 99:391-400. [DOI: 10.1016/j.antiviral.2013.06.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/26/2013] [Accepted: 06/28/2013] [Indexed: 11/30/2022]
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79
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Abstract
PURPOSE OF REVIEW One of the major obstacles in fully understanding HIV transmission comes from the impracticality of studying transmission in humans. Because of this encumbrance, the early phases of HIV transmission and systemic dissemination are poorly understood. In order to fully comprehend these critical steps in HIV infection, animal models must be devised to accurately reflect HIV's mode of action. This review seeks to highlight the essential nature of modelling HIV transmission in nonhuman primates (NHPs). RECENT FINDINGS Recently, it was discovered that HIV infection is established in newly infected recipients by a single or few transmitted/founder variants. This has reshaped how animal modelling is conducted with researchers currently recapitulating a physiologically relevant, low-titre infection. Pertinent animal models have been established for the most common routes of infection, including rectal, vaginal and penile transmission; models for intravenous and oral transmission are still in developmental stages. SUMMARY These limited dose models now accurately reflect HIV transmission in humans and provide a realistic experimental platform for vaccine development and other intervention strategies that can be used to inform vaccine development in humans. Using information obtained in NHP and human trials, it is conceivable to envision effective prevention modalities in the near future.
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Affiliation(s)
- Christine M. Fennessey
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Brandon F. Keele
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
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80
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Abstract
PURPOSE OF REVIEW Current antiretroviral treatment regimens represent significant improvements in the management of HIV-1 infection; however, these regimens have not achieved a functional or sterilizing cure. One barrier to achieving a cure may be suboptimal antiretroviral concentrations in sanctuary sites throughout the body, including the central nervous system, gut-associated lymphoid tissue, lymph nodes, and tissue macrophages. This review will focus on the problems associated with achieving effective concentrations in these restricted sanctuary sites, and potential strategies to overcome these barriers. RECENT FINDINGS Sufficient data exist to conclude that antiretroviral drug distribution is not uniform throughout the body. Low tissue/reservoir concentrations may be associated with viral replication. Multiple means to increase drug concentrations in sanctuary sites are being investigated, including modification of currently utilized drugs, blockade of transporters and enzymes that affect drug metabolism and pharmacokinetics, and local drug administration. Accumulating data suggest these methods increase antiretroviral concentrations in reservoirs of viral replication. No method has yet resulted in the complete clearance of HIV. SUMMARY New strategies for increasing antiretroviral concentrations in predominant sites of viral replication may provide more effective means for elimination of viral sanctuaries. Additional research is necessary to optimize antiretroviral tissue distribution in order to inhibit virus replication fully, and avoid resistance and replenishment of viral reservoirs that may persist in the face of antiretroviral therapy.
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Affiliation(s)
- Theodore J. Cory
- Antiviral Pharmacology Laboratory, University of Nebraska Medical Center
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81
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Abstract
PURPOSE OF REVIEW Oral and topical pre-exposure prophylaxis (PrEP) with antiretroviral drugs are novel biomedical interventions recently found to prevent HIV transmission among high-risk populations. In this review, we outline lessons learned from animal studies and discuss next steps in preclinical PrEP research including the study of new PrEP modalities, pharmacologic correlates of protection, and biological factors that may modulate PrEP efficacy. RECENT FINDINGS Studies using macaque or humanized mice models of mucosal simian immunodeficiency virus (SIV), HIV, or simian/human immunodeficiency virus (SHIV) transmission have provided efficacy data against rectal and vaginal infection. A multitude of oral and topical PrEP regimens including drugs such as tenofovir (TFV), tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) were tested against either wild-type or drug-resistant viruses. These models have also helped define prophylactic windows of protection of nondaily dosing and are being used increasingly to study pharmacokinetic and pharmacodynamic relationships. SUMMARY As human data from PrEP trials validate animal models or help fine tune them, it is expected that these models will play increasingly important roles in PrEP development as the field extends into new drug classes and combinations, episodic dosing, and novel long-acting drug formulations. By providing both efficacy and pharmacologic information these models can define correlates and mechanisms of protection, inform dose selection, and advance the most promising PrEP candidates and dosing modalities.
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82
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Abstract
The global HIV epidemic cannot be controlled by current treatment or prevention strategies. Pre-exposure prophylaxis (PrEP) using antiretrovirals is a promising approach to curbing the spread of HIV transmission. Recently, four clinical trials demonstrated favorable results when antiretroviral PrEP was administered topically or orally. However, two additional trials were unable to demonstrate a benefit, indicating that further study is required to define the populations and conditions under which PrEP will be effective. Adherence is highly correlated with protection, yet the exact level of adherence required is unknown. Future studies may require increased drug exposure testing and more objective methods to monitor adherence in real-time. Although the development of drug resistance in the PrEP trials has been low, it remains a concern, as therapeutic options could be compromised for those who seroconvert while on PrEP.
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83
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Derby N, Zydowsky T, Robbiani M. In search of the optimal delivery method for anti-HIV microbicides: are intravaginal rings the way forward? Expert Rev Anti Infect Ther 2013; 11:5-8. [PMID: 23428097 PMCID: PMC4771061 DOI: 10.1586/eri.12.155] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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84
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Aravantinou M, Singer R, Derby N, Calenda G, Mawson P, Abraham CJ, Menon R, Seidor S, Goldman D, Kenney J, Villegas G, Gettie A, Blanchard J, Lifson JD, Piatak M, Fernández-Romero JA, Zydowsky TM, Teleshova N, Robbiani M. The nonnucleoside reverse transcription inhibitor MIV-160 delivered from an intravaginal ring, but not from a carrageenan gel, protects against simian/human immunodeficiency virus-RT Infection. AIDS Res Hum Retroviruses 2012; 28:1467-75. [PMID: 22816564 PMCID: PMC3484820 DOI: 10.1089/aid.2012.0080] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
We previously showed that a carrageenan (CG) gel containing 50 μM MIV-150 (MIV-150/CG) reduced vaginal simian/human immunodeficiency virus (SHIV)-RT infection of macaques (56%, p>0.05) when administered daily for 2 weeks with the last dose given 8 h before challenge. Additionally, when 100 mg of MIV-150 was loaded into an intravaginal ring (IVR) inserted 24 h before challenge and removed 2 weeks after challenge, >80% protection was observed (p<0.03). MIV-160 is a related NNRTI with a similar IC(50), greater aqueous solubility, and a shorter synthesis. To objectively compare MIV-160 with MIV-150, herein we evaluated the antiviral effects of unformulated MIV-160 in vitro as well as the in vivo protection afforded by MIV-160 delivered in CG (MIV-160/CG gel) and in an IVR under regimens used with MIV-150 in earlier studies. Like MIV-150, MIV-160 exhibited potent antiviral activity against SHIV-RT in macaque vaginal explants. However, formulated MIV-160 exhibited divergent effects in vivo. The MIV-160/CG gel offered no protection compared to CG alone, whereas the MIV-160 IVRs protected significantly. Importantly, the results of in vitro release studies of the MIV-160/CG gel and the MIV-160 IVR suggested that in vivo efficacy paralleled the amount of MIV-160 released in vitro. Hundreds of micrograms of MIV-160 were released daily from IVRs while undetectable amounts of MIV-160 were released from the CG gel. Our findings highlight the importance of testing different modalities of microbicide delivery to identify the optimal formulation for efficacy in vivo.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Agegnehu Gettie
- Aaron Diamond AIDS Research Center, Rockefeller University, New York, New York
| | - James Blanchard
- Tulane National Primate Research Center, Tulane University, Covington, Louisiana
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., National Cancer Institute, Frederick, Maryland
| | - Michael Piatak
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., National Cancer Institute, Frederick, Maryland
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85
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Kenney J, Singer R, Derby N, Aravantinou M, Abraham CJ, Menon R, Seidor S, Zhang S, Gettie A, Blanchard J, Piatak M, Lifson JD, Fernández-Romero JA, Zydowsky TM, Robbiani M. A single dose of a MIV-150/Zinc acetate gel provides 24 h of protection against vaginal simian human immunodeficiency virus reverse transcriptase infection, with more limited protection rectally 8-24 h after gel use. AIDS Res Hum Retroviruses 2012; 28:1476-84. [PMID: 22737981 DOI: 10.1089/aid.2012.0087] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Previously we showed that repeated vaginal application of a MIV-150/zinc acetate carrageenan (MIV-150/ZA/CG) gel and a zinc acetate carrageenan (ZA/CG) gel significantly protected macaques from vaginal simian human immunodeficiency virus reverse transcriptase (SHIV-RT) infection. Gels were applied either daily for 2 weeks or every other day for 4 weeks, and the animals were challenged 4-24 h later. Herein, we examined the effects of a single vaginal dose administered either before or after virus challenge. Encouraged by the vaginal protection seen with MIV-150/ZA/CG, we also tested it rectally. Vaginal applications of MIV-150/ZA/CG, ZA/CG, and CG gel were performed once 8-24 h before, 1 h after, or 24 h before and 1 h after vaginal challenge. Rectal applications of MIV-150/ZA/CG and CG gel were performed once 8 or 24 h before rectal challenge. While vaginal pre-challenge and pre/post-challenge application of MIV-150/ZA/CG gel offered significant protection (88%, p<0.002), post-challenge application alone did not significantly protect. ZA/CG gel reduced infection prechallenge, but not significantly, and the effect was completely lost post-challenge. Rectal application of MIV-150/ZA/CG gel afforded limited protection against rectal challenge when applied 8-24 h before challenge. Thus, MIV-150/ZA/CG gel is a highly effective vaginal microbicide that demonstrates 24 h of protection from vaginal infection and may demonstrate efficacy against rectal infection when given close to the time of HIV exposure.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Agegnehu Gettie
- Aaron Diamond AIDS Research Center, Rockefeller University, New York, New York
| | - James Blanchard
- Tulane National Primate Research Center, Tulane University, Covington, Louisiana
| | - Michael Piatak
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., National Cancer Institute, Frederick, Maryland
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., National Cancer Institute, Frederick, Maryland
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86
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Grammen C, Augustijns P, Brouwers J. In vitro profiling of the vaginal permeation potential of anti-HIV microbicides and the influence of formulation excipients. Antiviral Res 2012; 96:226-33. [PMID: 23000496 DOI: 10.1016/j.antiviral.2012.09.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Revised: 08/31/2012] [Accepted: 09/12/2012] [Indexed: 12/22/2022]
Abstract
In the search for an effective anti-HIV microbicidal gel, limited drug penetration into the vaginal submucosa is a possible reason for failed protection against HIV transmission. To address this issue in early development, we here describe a simple in vitro strategy to predict the tissue permeation potential of vaginally applied drugs, based on solubility, permeability and flux assessment. We demonstrated this approach for four model microbicides (tenofovir, darunavir, saquinavir mesylate and dapivirine) and additionally examined the influence of formulation excipients on the permeation potential. When formulated in an aqueous-based HEC gel, high flux values across an HEC-1A cell layer were reached by tenofovir, as a result of its high aqueous solubility. In contrast, saquinavir and dapivirine fluxes remained low due to poor permeability and solubility, respectively. These low fluxes suggest limited in vivo tissue penetration, possibly leading to lack of efficacy. Dapivirine fluxes, however, could be enhanced up to 30-fold, by including formulation excipients such as polyethylene glycol 1000 (20%) or cyclodextrins (5%) in the HEC gels. Alternative formulations, i.e. emulsions or silicone elastomer gels, were less effective in flux enhancement compared to cyclodextrin-HEC gels. In conclusion, implementing the proposed solubility and permeability profiling in early microbicide development may contribute to the successful selection of promising microbicide candidates and appropriate formulations.
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Affiliation(s)
- Carolien Grammen
- Laboratory for Pharmacotechnology and Biopharmacy, KU Leuven, Belgium
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87
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Safety and pharmacokinetics of intravaginal rings delivering tenofovir in pig-tailed macaques. Antimicrob Agents Chemother 2012; 56:5952-60. [PMID: 22964245 DOI: 10.1128/aac.01198-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Antiretroviral-based microbicides applied topically to the vagina may play an important role in protecting women from HIV infection. Incorporation of the nucleoside reverse transcriptase inhibitor tenofovir (TFV) into intravaginal rings (IVRs) for sustained mucosal delivery may lead to increased microbicide product adherence and efficacy compared with those of conventional vaginal formulations. Formulations of a novel "pod IVR" platform spanning a range of IVR drug loadings and daily release rates of TFV were evaluated in a pig-tailed macaque model. The rings were safe and exhibited sustained release at controlled rates over 28 days. Vaginal secretion TFV levels were independent of IVR drug loading and were able to be varied over 1.5 log units by changing the ring configuration. Mean TFV levels in vaginal secretions were 72.4 ± 109 μg ml(-1) (slow releasing) and 1.84 ± 1.97 mg ml(-1) (fast releasing). The mean TFV vaginal tissue concentration from the slow-releasing IVRs was 76.4 ± 54.8 μg g(-1) and remained at steady state 7 days after IVR removal, consistent with the long intracellular half-life of TFV. Intracellular tenofovir diphosphate (TFV-DP), the active moiety in defining efficacy, was measured in vaginal lymphocytes collected in the study using the fast-releasing IVR formulation. Mean intracellular TFV-DP levels of 446 ± 150 fmol/10(6) cells fall within a range that may be protective of simian-human immunodeficiency virus strain SF162p3 (SHIV(SF162p3)) infection in nonhuman primates. These data suggest that TFV-releasing IVRs based on the pod design have potential for the prevention of transmission of human immunodeficiency virus type 1 (HIV-1) and merit further clinical investigation.
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88
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Clark JT, Johnson TJ, Clark MR, Nebeker JS, Fabian J, Tuitupou AL, Ponnapalli S, Smith EM, Friend DR, Kiser PF. Quantitative evaluation of a hydrophilic matrix intravaginal ring for the sustained delivery of tenofovir. J Control Release 2012; 163:240-8. [PMID: 22981701 DOI: 10.1016/j.jconrel.2012.08.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/22/2012] [Accepted: 08/31/2012] [Indexed: 10/27/2022]
Abstract
In vitro testing and quantitative analysis of a matrix, hydrophilic polyether urethane (HPEU) intravaginal ring (IVR) for sustained delivery of the anti-HIV agent tenofovir (TFV) are described. To aid in device design, we employed a pseudo-steady-state diffusion model to describe drug release, as well as an elastic mechanical model for ring compression to predict mechanical properties. TFV-HPEU IVRs of varying sizes and drug loadings were fabricated by hot-melt extrusion and injection molding. In vitro release rates of TFV were measured at 37 °C and pH 4.2 for 30 or 90 days, during which times IVR mechanical properties and swelling kinetics were monitored. Experimental data for drug release and mechanical properties were compared to model predictions. IVRs loaded with 21% TFV (w/w) released greater than 2mg TFV per day for 90 days. The diffusion model predicted 90 day release data by extrapolating forward from the first 7 days of data. Mechanical properties of IVRs were similar to NuvaRing, although the matrix elastic modulus decreased up to three-fold following hydration. This is the first vaginal dosage form to provide sustained delivery of milligram quantities of TFV for 90 days. Drug release and mechanical properties were approximated by analytical models, which may prove useful for the continuing development of IVRs for HIV prevention or other women's health indications.
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Affiliation(s)
- Justin T Clark
- Department of Bioengineering, University of Utah, 20 South 2030 East, Salt Lake City, UT 84112, USA
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89
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Singer R, Mawson P, Derby N, Rodriguez A, Kizima L, Menon R, Goldman D, Kenney J, Aravantinou M, Seidor S, Gettie A, Blanchard J, Piatak M, Lifson JD, Fernández-Romero JA, Robbiani M, Zydowsky TM. An intravaginal ring that releases the NNRTI MIV-150 reduces SHIV transmission in macaques. Sci Transl Med 2012; 4:150ra123. [PMID: 22956201 PMCID: PMC4391747 DOI: 10.1126/scitranslmed.3003936] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Microbicides may prevent HIV and sexually transmitted infections (STIs) in women; however, determining the optimal means of delivery of active pharmaceutical ingredients remains a major challenge. We previously demonstrated that a vaginal gel containing the non-nucleoside reverse transcriptase inhibitor MIV-150 partially protected macaques from SHIV-RT (simian/HIV reverse transcriptase) infection, and the addition of zinc acetate rendered the gel significantly protective. We test the activity of MIV-150 without the addition of zinc acetate when delivered from either ethylene vinyl acetate (EVA) or silicone intravaginal rings (IVRs). MIV-150 was successfully delivered, because it was detected in vaginal fluids and tissues by radioimmunoassay in pharmacokinetic studies. Moreover, EVA IVRs significantly protected macaques from SHIV-RT infection. Our results demonstrate that MIV-150-containing IVRs have the potential to prevent HIV infection and highlight the possible use of IVRs for delivering drugs that block HIV and other STIs.
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Affiliation(s)
- Rachel Singer
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Paul Mawson
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Nina Derby
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Aixa Rodriguez
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Larisa Kizima
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Radhika Menon
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Daniel Goldman
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Jessica Kenney
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Meropi Aravantinou
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Samantha Seidor
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Agegnehu Gettie
- Aaron Diamond AIDS Research Center, Rockefeller University, New York, NY 10065, USA
| | - James Blanchard
- Tulane National Primate Research Center, Tulane University, Covington, LA 70433, USA
| | - Michael Piatak
- AIDS and Cancer Virus Program, SAIC-Frederick, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, SAIC-Frederick, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | | | - Melissa Robbiani
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
| | - Thomas M. Zydowsky
- Center for Biomedical Research, Population Council, New York, NY 10065, USA
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90
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Duwal S, Schütte C, von Kleist M. Pharmacokinetics and pharmacodynamics of the reverse transcriptase inhibitor tenofovir and prophylactic efficacy against HIV-1 infection. PLoS One 2012; 7:e40382. [PMID: 22808148 PMCID: PMC3394807 DOI: 10.1371/journal.pone.0040382] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 06/05/2012] [Indexed: 11/18/2022] Open
Abstract
Antiviral pre-exposure prophylaxis (PrEP) through daily drug administration can protect healthy individuals from HIV-1 infection. While PrEP was recently approved by the FDA, the potential long-term consequences of PrEP implementation remain entirely unclear. The aim of this study is to predict the efficacy of different prophylactic strategies with the pro-drug tenofovir-disoproxil-fumarate (TDF) and to assess the sensitivity towards timing- and mode of TDF administration (daily- vs. single dose), adherence and the number of transmitted viruses. We developed a pharmacokinetic model for TDF and its active anabolite tenofovir-diphosphate (TFV-DP) and validated it with data from 4 different trials, including 4 distinct dosing regimes. Pharmacokinetics were coupled to an HIV model and viral decay following TDF mono-therapy was predicted, consistent with available data. Subsequently, a stochastic approach was used to estimate the % infections prevented by (i) daily TDF-based PrEP, (ii) one week TDF started either shortly before, or -after viral exposure and (iii) a single dose oral TDF before viral challenge (sd-PrEP). Analytical solutions were derived to assess the relation between intracellular TFV-DP concentrations and prophylactic efficacy. The predicted efficacy of TDF was limited by a slow accumulation of active compound (TFV-DP) and variable TFV-DP half-life and decreased with increasing numbers of transmitted viruses. Once daily TDF-based PrEP yielded [Formula: see text]80% protection, if at least 40% of pills were taken. Sd-PrEP with 300 mg or 600 mg TDF could prevent [Formula: see text]50% infections, when given at least before virus exposure. The efficacy dropped to [Formula: see text]10%, when given 1 h before 24 h exposure. Efficacy could not be increased with increasing dosage or prolonged administration. Post-exposure prophylaxis poorly prevented infection. The use of drugs that accumulate more rapidly, or local application of tenofovir gel may overcome the need for drug administration long before virus exposure.
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Affiliation(s)
- Sulav Duwal
- Department of Mathematics and Computer Science, Free University Berlin, Berlin, Germany
| | - Christof Schütte
- Department of Mathematics and Computer Science, Free University Berlin, Berlin, Germany
| | - Max von Kleist
- Department of Mathematics and Computer Science, Free University Berlin, Berlin, Germany
- * E-mail:
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91
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Gengiah TN, Baxter C, Mansoor LE, Kharsany AB, Abdool Karim SS. A drug evaluation of 1% tenofovir gel and tenofovir disoproxil fumarate tablets for the prevention of HIV infection. Expert Opin Investig Drugs 2012; 21:695-715. [PMID: 22394224 PMCID: PMC3460694 DOI: 10.1517/13543784.2012.667072] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
INTRODUCTION More than a million people acquire HIV infection annually. Pre-exposure prophylaxis (PrEP) using antiretrovirals is currently being investigated for HIV prevention. Oral and topical formulations of tenofovir have undergone preclinical and clinical testing to assess acceptability, safety and effectiveness in preventing HIV infection. AREAS COVERED The tenofovir drug development pathway from compound discovery, preclinical animal model testing and human testing were reviewed for safety, tolerability and efficacy. Tenofovir is well tolerated and safe when used both systemically or applied topically for HIV prevention. High drug concentrations at the site of HIV transmission and concomitant low systemic drug concentrations are achieved with vaginal application. Coitally applied gel may be the favored prevention option for women compared with the tablets, which may be more suitable for prevention in men and sero-discordant couples. However, recent contradictory effectiveness outcomes in women need to be better understood. EXPERT OPINION Emerging evidence has brought new hope that antiretrovirals can potentially change the course of the HIV epidemic when used as early treatment for prevention, as topical or oral PrEP. Although some trial results appear conflicting, behavioral factors, adherence to dosing and pharmacokinetic properties of the different tenofovir formulations and dosing approaches offer plausible explanations for most of the variations in effectiveness observed in different trials.
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Affiliation(s)
- Tanuja N Gengiah
- Centre for the AIDS Program of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Doris Duke Medical Research Institute, Nelson R Mandela School of Medicine, Congella, Durban, South Africa.
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92
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Adams JL, Kashuba ADM. Formulation, pharmacokinetics and pharmacodynamics of topical microbicides. Best Pract Res Clin Obstet Gynaecol 2012; 26:451-62. [PMID: 22306523 DOI: 10.1016/j.bpobgyn.2012.01.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 01/16/2012] [Indexed: 11/26/2022]
Abstract
The development of safe topical microbicides that effectively prevent human immunodeficiency virus (HIV) infection is a major goal in curbing the human immunodeficiency virus pandemic. A number of past failures resulting from mucosal toxicity or lack of efficacy have informed the field. Products that caused toxicity to the female genital tract mucosa, and thereby increased the likelihood of HIV acquisition, included nonoxynol 9, cellulose sulfate, and C31 G vaginal gel Savvy. Topical products that were ineffective in preventing HIV infection include BufferGel, Carraguard, and PRO 2000. Antiretroviral drugs such as tenofovir and dapivirine formulated into microbicide products have shown promise, but there is much to learn about ideal product formulation and acceptability, and drug distribution and disposition (pharmacokinetics). Current formulations for water-soluble molecules include vaginally or rectally applied gels, vaginal rings, films and tablets. Dosing strategies (e.g. coitally dependent or independent) will be based on the pharmacokinetics of the active ingredient and the tolerance for less than perfect adherence.
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Affiliation(s)
- Jessica L Adams
- University of North Carolina at Chapel Hill, Eshelman School of Pharmacy 3315 Kerr Hall CB# 7569, Chapel Hill, North Caroina 27599-7569, USA.
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