BLT mice in HIV prophylaxis

Transcription

1 BLT mice in HIV prophylaxis Martina Kovarova, Ph.D. Assistant Professor UNC at Chapel Hill September 18, 2017

2 BLT mice Bone Marrow-Liver-Thymus Melkus, et al., Nature (2006)

3 BLT humanized mice preparation NOD/SCID/γc -/- (NSG) mice Irradiated Implanted with human thy/liv/thy under the kidney capsule Transplanted with hematopoietic CD34+ cells De novo-generated human immune system (hcd4+, hcd8+t cells, B cells, and myeloid cells) Distributed throughout each animal including mucosal tissue relevant for HIV transmission Model for diseases affecting specifically human immune cells.

4 HIV HIV stands for Human Immunodeficiency Virus. If left untreated, HIV can lead to the disease AIDS (Acquired ImmunoDeficiency Syndrome). At the end of 2016, 36.7 million people were living with HIV. No effective cure or vaccine for HIV currently exists. HIV exclusively infects cells of human immune system (CD4 T cells, macrophages)

5 Pre-exposure prophylaxis (PrEP) Prevention strategy using antiretroviral drug (ARV) regimen for people who are HIV-negative and at very high risk for HIV infection. Several clinical trials of ARVs tenofovir (TDF) and emtricitabine (FTC) showed efficacy of PrEP in various high risk populations. In 2012, FDA approved oral FTC-TDF (Truvada) for pre-exposure prophylaxis in risk populations

6 BLT Humanized Mice as a preclinical models Systemic PrEP administration prevents : Vaginal HIV transmission (Denton P. et al. PLOS Medicine, 2008) Oral HIV transmission (Wahl A. et al. PLOS Pathogens, 2012) Intravenous HIV transmission (Denton P. et al PLOS One, 2010) Rectal HIV transmission (Denton P. et al PLOS One, 2010) Topical PrEP administration prevents : Vaginal HIV transmission (Kovarova M., Council O. et al. PLOS Pathogens 2015) (Denton et al. Journal of Virology 2011) (Neff CP. et al. PLOS One 2011) Rectal HIV transmission (Chateau M. et al. PLOS One, 2013) Long-acting PrEP prevents: for HIV PrEP Vaginal HIV transmission (Kovarova M., Council O. et al. PLOS Pathogens, 2015) (Kovarova M, et al. J. Antimicrob Chemother, 2016a)

7 Pre-exposure prophylaxis (PrEP) Name Risk population Drugs CAPRISA 004 iprex Partners PrEP TDF2 study African women MSM HIV-1 serodiscordant heterosexual couples Heterosexual men and women 1% tenofovir gel or placebo FTC-TDF or placebo TDF FTC-TDF or placebo FTC-TDF or placebo Route of administration Reduction in the HIV incidence Topical, vaginal 39% Systemic, oral 44% Systemic, oral 67% 75% Systemic, oral 62% Bangkok Tenofovir Study Injecting drug users TDF or placebo Systemic, oral 49%

8 Pre-exposure prophylaxis (PrEP) Name Risk population Drugs CAPRISA 004 iprex Partners PrEP TDF2 study African women MSM HIV-1 serodiscordant heterosexual couples Heterosexual men and women 1% tenofovir gel or placebo FTC-TDF or placebo TDF FTC-TDF or placebo FTC-TDF or placebo Route of administration Reduction in the HIV incidence Topical, vaginal 39% Systemic, oral 44% Systemic, oral 67% 75% Systemic, oral 62% Bangkok Tenofovir Study Injecting drug users TDF or placebo Systemic, oral 49%

9 Modeling CAPRISTA 004 trial in BLT mice Experimental design One Percent Tenofovir Applied Topically to Humanized BLT Mice and Used According to the CAPRISA 004 Experimental Design Demonstrates Partial Protection from Vaginal HIV Infection, Validating the BLT Model for Evaluation of New Microbicide Candidates Denton et al. Journal of Virology 2011

10 Modeling CAPRISTA 004 trial in BLT mice 3 out of 4 untreated (control) BLT mice were infected CD8 T cells 1 out of 8 treated BLT mice were infected (87% protection) CD4 T cells CD8 T cells CD4 T cells Denton et al. Journal of Virology 2011

11 Modeling CAPRISTA 004 trial in BLT mice Synopisis Evaluation is shorter compared to clinical trials Evaluation of protection, infection and drug concentration in tissues 100% compliance with drug regimen These results validate BLT mice as a model for evaluation of PrEP in pre-clinical studies

12 Efficacy of PrEP depends on compliance with drug regimen Name Risk population Drugs CAPRISA 004 African women 1% tenofovir gel or placebo Route of administration Reduction in the HIV incidence Topical, vaginal 39% BLT mice: 87% protection Detail CAPRISA results: High adherence to gel (>80%) led to 54% lower HIV incidence Intermediate adherence to gel (50%-80%) led to 38% lower HIV incidence Low adherence to gel (<50%) led to 28% lower HIV incidence Q.A. Karim et al, Science, 2010

13 New approaches in PrEP Efficacy of PrEP depends on compliance with drug regimen New PrEP should be convenient to use, highly effective, ideally long acting Topical microbicides: ARV encapsulation in nanoparticles Thermosensitive gels Long acting formulations: Nanosuspensions New drugs High potency Distribution to target tissues Accumulation in cells/tissues

14 New approaches in PrEP Efficacy of PrEP depends on compliance with drug regimen New PrEP should be convenient to use, highly effective, ideally long acting Topical microbicides: ARV encapsulation in nanoparticles Thermosensitive gels Long acting formulations: Nanosuspensions New drugs High potency Distribution to target tissues Accumulation in cells/tissues

15 Evaluation of topical microbicides for PrEP in BLT mice-experimental design Kovarova M., Council O.D. et al., PLOS Pathogens 2015 Topically (vaginally) applied rilpivirine encapsulated in PLGA nanoparticles Delivered in a thermosensitive gel, which becomes solid at body temperature. Generation and validation of BLT mice RPV-PLGA administration HIV-1 challenge Necropsy tissue analysis -1.5h or -24 h 0 Weekly analysis of vrna

16 Distribution of rhodamine nanoparticles in female reproductive tract of BLT mice Kovarova M., Council O.D. et al., PLOS Pathogens 2015

17 Rilpivirine in PLGA nanoparticles protects from vaginal HIV transmission 1.5h after treatment: 0 out of 4 BLT mice were infected (100% protection) 4 out of 4 untreated (control ) BLT mice were infected 24 h after treatment: 4 out of 8 mice were infected (50% protection) 4 out of 4 untreated (control ) BLT mice were infected Synopsis: Rilpivirine encapsulated in PLGA nanoparticles in thermosensitive gel protects from vaginal HIV transmission when administered 1.5 h before HIV challenge. This protection is reduced 24 h post-administration

18 New approaches in PrEP Efficacy of PrEP depends on compliance with drug regimen New PrEP should be convenient to use, highly effective, ideally long acting Topical microbicides: ARV encapsulation in nanoparticles Thermosensitive gels Long acting formulations: Nanosuspensions New drugs High potency Distribution to target tissues Accumulation in cells/tissues

19 Evaluation of long-acting drug formulation for PrEP in BLT mice Long-acting nanosuspension of rilpivirine Kovarova M., Council O.D. et al., PLOS Pathogens 2015 Drugs milled to micron size, coated with surfactants, administered intramuscularly Experimental design: Ç Ç

20 Long-acting nanosuspension of rilpivirine protects from vaginal HIV transmission 1 week after drug administration (2 independent experiments): 9 out of 10 untreated (control) BLT mice infected 3 out of 16 treated BLT mice infected (81% protection) 4 weeks after drug administration (1 experiment): 6 out of 6 untreated (control) BLT mice infected 5 out of 10 treated BLT mice infected (50% protection)

21 New approaches in PrEP Efficacy of PrEP depends on compliance with drug regimen New PrEP should be convenient to use, highly effective, ideally long acting Topical microbicides: ARV encapsulation in nanoparticles Thermosensitive gels Long acting formulations: Nanosuspensions New drugs High potency Distribution to target tissues Accumulation in cells/tissues

22 4-ethynyl-2-fluoro-2ʹ-deoxyadenosine (EFdA) Nucleoside reverse transcriptase translocation inhibitor EFdA is a adenosine derivate Low toxicity, highly selective and effective inhibitor, IC nm EFdA is effective not only against wild-type HIV but also against drug-resistant strains (Nakata H. el al. Antimicrob Agents Chemother. 2007, Michailidis E. et al. Retrovirology 2013, Michailidis E. et al. J. Biol.Chem. 2014, Zhang W. Drug Dev Ind Pharm 2014)

23 Evaluation of EFdA for PrEP in BLT mice Kovarova M. et al., J. Antimicrob. Chemother. 2016b HIV pre-exposure prophylaxis for women and infants prevents vaginal and oral HIV transmission in a pre-clinical model of HIV infection Prevention of vaginal HIV transmission Prevention of oral HIV transmission Experimental design:

24 Evaluation of EFdA for prevention of vaginal HIV transmission 6 out of 6 untreated control BLT mice infected 0 out of 11 treated BLT mice infected (100% protection) P= EFdA protects from vaginal HIV transmission Kovarova M. et al., J. Antimicrob. Chemother. 2016b

25 Evaluation of EFdA for prevention of oral HIV transmission 5 out of 5 untreated control BLT mice infected 1 out of 8 treated BLT mice infected (88% protection) P= EFdA protects from oral HIV transmission Kovarova M. et al., J. Antimicrob. Chemother. 2016b

26 Conclusions BLT mice can be used for pre-clinical studies to evaluate various approaches in PrEP: Various HIV-1 transmission routes (vaginal, oral) Various routes of drug administration (topical, systemic-oral; parenteral-intramuscular) New technologies in drug formulations for PrEP (nanoparticles, nanosuspensions) New, more efficient drugs