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Models for predicting effective HIV chemoprevention in women - PubMed

  • ️Thu Jan 01 2015

Models for predicting effective HIV chemoprevention in women

Melanie R Nicol et al. J Acquir Immune Defic Syndr. 2015.

Abstract

Objective: Model systems that rapidly identify tissue drug concentrations protective of HIV infection could streamline the development of chemoprevention strategies. Tissue models are promising, but limited concentration targets exist, and no systematic comparison to cell models or clinical studies has been performed.

Design: We explored the efficacy of maraviroc (MVC) and tenofovir (TFV) for HIV prevention by comparing Emax models from TZM-bl cells to vaginal tissue explants and evaluated their predictive capabilities with a dose-challenge clinical study.

Methods: HIV-1JR-CSF was used for viral challenge. Drug efficacy was assessed using a luciferase reporter assay in TZM-bl cells and real-time PCR to quantify spliced RNA in a tissue explant model. Cell and tissue concentrations of MVC, TFV, and the active metabolite tenofovir diphosphate were measured by liquid chromatography with tandem mass spectrometry and used to create Emax models of efficacy. Efficacy after a single oral dose of 600 mg MVC and 600 mg tenofovir disoproxil fumarate was predicted from cell and tissue models and confirmed in a clinical study with viral biopsy challenge postdose.

Results: TFV was >10-fold and MVC >1000-fold, more potent in TZM-bl cells compared with vaginal explant tissue. In the dose-challenge study, tissues from 3 of 6 women were protected from HIV infection, which was 49% lower than predicted by TZM-bl data and 36% higher than predicted by tissue explant data.

Conclusions: Comparative effective concentration data were generated for TFV and MVC in 3 HIV chemoprophylaxis models. These results provide a framework for future early investigations of antiretroviral efficacy in HIV prevention to optimize dosing strategies in clinical investigations.

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Conflict of interest statement

Conflicts of Interest: The authors declare no conflict of interest regarding the submitted work.

Figures

Figure 1
Figure 1. Spliced RNA assay detects early HIV replication in vaginal explants

A) Spliced viral RNA and replication in explant tissue. Explant tissues were infected with 107 TCID50/ well HIV-1 JR-SF. Baseline samples (Day 0) were harvested immediately following the end of the 3 hour viral incubation. Copy number of spliced RNA was determined using real-time PCR after reverse transcription and the fold change from baseline is reported (median/IQR). B) Rapid changes occur in explant tissue over time in culture. All values were normalized to an explant from the same tissue donor at Day 0 (100%). Symbols represent the median values and error bars represent the Interquartile Range for MTT viability; error bars represent range for CCR5 gene expression, CD3/CD4 IHC cell counts, and dATP/dCTP concentrations.

Figure 2
Figure 2. Antiretrovirals are rapidly taken up by tissue and rapidly eliminated

Antiretroviral concentrations in tissue are reported as the percent initial concentration of the media tissues were incubated in assuming a tissue density of 1 g/mL. Symbols represent median values and errors represent range. Tissues incubated in MVC (2-4 explants per time point from a total of 10 donors) were rinsed at 24 hours (dashed arrow and transferred to a drug-free culture plate. Tissues incubated in TFV (2-6 explants per time point from total of 9 donors) were rinsed at 48 hours (solid arrow). Inset: Formation and elimination of TFVdp from explant tissue. Explants from two vaginal donors were used to evaluate the rate of TFVdp formation over 48 hours of incubation in 100 ug/mL TFV. Explants from a separate three donors were used to evaluate the rate that TFVdp was eliminated from tissues. Explants were incubated in 100 ug/mL TFV for 24-48 hours, rinsed in culture media, and transferred to gelfoam raft. 48 hours represents the time the tissues were removed from TFV incubation (black arrow). Symbols represent median values and error bars represent range.

Figure 3
Figure 3. Concentration response relationship of TFV, TFVdp, and MVC in Vaginal Explants and TZM-bl cells

Vaginal explants were incubated in TFV or MVC for 24 hours prior to a 3 hour viral exposure to 107 TCID50/ well HIV-1JR-CSF. TFVdp concentrations were measured at the time of viral exposure. TZM-bl cells were incubated in TFV or MVC for 24 hours prior to viral exposure. Symbols represent the raw data while the lines represent the predictions from the best fit Emax models. A) Percent inhibition versus the concentration of TFV in medium. B) Percent inhibition vs TFVdp measured in tissue explants. Percent inhibition in explant tissues was determined by comparing the weight-normalized spliced RNA AUC24-72h of the ARV-treated tissues to the untreated positive controls. Percent inhibition in TZM-bl cells was determined by comparing the relative light units (RLU) to positive control (untreated cells) in a luciferase reporter assay. C) Percent inhibition in explant tissue vs MVC concentration in medium was determined by comparing the weight- normalized spliced RNA at 24 hours post-inoculation.

Figure 4
Figure 4. Protection of mucosal biopsies from HIV following high dose of oral maraviroc and tenofovir

Two vaginal and two cervical biopsies were collected from all study participants 24 hours after a 600/600 mg dose of MVC/TDF and challenged within 30 minutes of collection with a three hour viral exposure to 107 TCID50/ well HIV-1JR-CSF. Spliced RNA was measured in tissues at one and two days post-inoculation. The dark dashed line represents the pre-determined infection cutoff of 434 copies/mg. Open symbols represent vaginal tissues. Closed symbols represent cervical tissues. The same symbols represent tissues from the same subject.

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References

    1. UNAIDS. [Assessed November 12, 2013];UNAIDS report on the global AIDS epidemic. 2012 http://www.unaids.org/en/media/unaids/contentassets/documents/epidemiolo....
    1. Abdool Karim Q, Abdool Karim SS, Frohlich JA, et al. Effectiveness and safety of tenofovir gel, an antiretroviral microbicide, for the prevention of HIV infection in women. Science. 2010;329:1168–1174. - PMC - PubMed
    1. Baeten JM, Donnell D, Ndase P, et al. Antiretroviral prophylaxis for HIV prevention in heterosexual men and women. N Engl J Med. 2012;367:399–410. - PMC - PubMed
    1. Grant RM, Lama JR, Anderson PL, et al. Preexposure chemoprophylaxis for HIV prevention in men who have sex with men. N Engl J Med. 2010;363:2587–2599. - PMC - PubMed
    1. Thigpen MC, Kebaabetswe PM, Paxton LA, et al. Antiretroviral preexposure prophylaxis for heterosexual HIV transmission in Botswana. N Engl J Med. 2012;367:423–434. - PubMed

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