Approaching HIV prevention with young women’s preferences in mind
To many scientists, it may seem that HIV prevention research has succeeded – large clinical trials of oral pre-exposure prophylaxis (PrEP) and vaginal formulations of antiretroviral drugs (ARVs) demonstrated that these products can indeed prevent HIV infection when used [1-3]. This is great news! But the problem we face as a global HIV prevention community is not whether or not we have efficacious products. The problem is whether or not the products will appropriately meet women’s needs and lifestyles and thus whether or not women will use them. Adherence to product use is quite possibly the biggest issue blocking the eradication of sexual HIV transmission .
The paper in Nature Communications is here: go.nature.com/2xB816j
The Population Council has been tackling HIV prevention with a holistic bench to bedside approach that incorporates the importance of adherence and its driving factors, including acceptability, for many years . Comprised of formulation chemists, basic biologists, pre-clinical and clinical researchers, and behavioral scientists, the Council understands that if women don’t like a product or its components or the product doesn’t fit into their way of life, they can’t be expected to use it. In the same vein that there are now many options for contraception used by women in different geographical regions and different phases of life, there also need to be many options for HIV prevention. These should range from long-acting to on-demand, and from ARV-based, to over-the-counter.
Moreover, the role that other sexually transmitted infections (STIs) play in HIV infection needs to be considered. Many STIs, including herpes simplex virus (HSV) and human papillomavirus (HPV) increase HIV susceptibility and exhibit intertwined epidemiology with HIV [6-11]. A multipurpose prevention technology (MPT) product that prevents HSV and HPV infections along with HIV may exhibit greater efficacy than an HIV-only product and may even be of greater interest to women.
Over the years, Council scientists have worked to develop HIV prevention products understanding the importance of women’s choice. Before ARVs were tested for topical protection, microbicides were all non-ARV-based . Like all other early generation non-specific microbicides, the Council’s non-ARV microbicide, Carraguard (comprised of the seaweed polysaccharide carrageenan [CG]) was not effective at significantly preventing HIV infection in women [13, 14]. Nonetheless, CG proved to be highly effective against HPV in animal models and women [15-19], possess some activity against HSV in vitro and in animals [20, 21], and assist in the delivery and activity of other antiviral agents [12, 22].
Although the Council went on to develop ARV microbicides with strong preclinical activity based on the non-nucleoside reverse transcriptase inhibitor MIV-150) [12, 19, 22-32], we always retained an appreciation of the importance of giving women options in how they protect themselves, and we never lost sight of the role that non-ARVs and MPTs have to play. Compared to ARVs, non-ARVs are less likely to promote drug resistance, may afford fewer lasting side effects associated with long term use, and may be obtainable without a prescription, an important consideration for young women. Currently there are no strictly non-ARV microbicide options in the development pipeline .
In 2009, Dr. Barry O’Keefe at the Natural Products Branch within the National Cancer Institute discovered that a non-ARV lectin derived from red algae, Griffithsin (GRFT, Fig. 1), possessed picomolar activity against HIV infection in vitro .
Figure 1. A nature print of the Griffithsia algae by Henry Bradbury, 1859.
When GRFT was demonstrated to be safer and more potent than other promising lectins [35, 36], and when we were given the opportunity to work with it, Council scientists quickly developed a plan to secure funding from USAID to develop GRFT into a variety of HIV prevention products and MPTs with activity against HSV and HPV as well as HIV.
Initial efficacy results from the Council on GRFT came from Dr. Jose Fernandez-Romero’s lab. He showed that an early on-demand formulation of GRFT/CG, the vaginal gel, significantly reduced HSV-2 and HPV pseudovirus infections in murine models , supporting other data on GRFT for HSV prevention . However, rather than test gels for anti-HIV activity in vivo, we explored other, potentially more acceptable (e.g. less bulky and costly; more discreet), formulations for on-demand vaginal protection. The right formulation also had to ensure the stability of GRFT, a protein with high oxidation susceptibility.
To achieve these goals, Dr. Thomas Zydowsky, Senior Scientist and Director of Biomedical Research and Pharmaceutical Development at the Council, initiated a collaboration with Dr. Manjari Lal at Seattle-based PATH to formulate GRFT and CG in a stable, freeze-dried, fast-dissolving vaginal insert (FDI, Fig. 2). Ideally, the FDI should dissolve within minutes, releasing GRFT and CG into the vaginal fluid as a gel to spread throughout the vagina. Working together with Dr. Ugaonkar in the Zydowsky lab at the Council, Dr. Lal demonstrated that GRFT/CG could indeed be formulated in an FDI and that GRFT remained stable in the FDI even under high stress conditions, such as the elevated temperature and humidity sustained in many developing countries .
Figure 2. Human-sized vaginal fast dissolving insert (FDI) comprised of active pharmaceutical ingredients GRFT and CG. Excipients are dextran-40, sucrose, and mannitol.
Once two lead FDIs emerged from stability testing, we began testing in animal models for safety, pharmacokinetics (PK), pharmacodynamics, and antiviral efficacy. Excitement built as each test produced positive data. These data form the results of the Nature Communications manuscript associated with this post.
First, we demonstrated that the FDIs are safe, produce expected PK profiles in vivo, and prevent HSV and HPV infections. Dr. Fernandez-Romero showed that like for the gel formulation, FDIs administered four hours before virus challenge, significantly reduce vaginal HSV-2 and HPV psuedovirus infections in mice. Dr. Teleshova showed that the FDIs do not promote vaginal inflammation in rhesus macaques, and that high concentrations of GRFT are achievable in macaque vaginal fluids and sustained up to eight hours after FDI insertion. Drs. Fernandez-Romero and Teleshova together confirmed that the macaque vaginal fluids possess potent anti-HIV activity in TZMbl cells and in the mucosal targets of infection using a tissue explant model.
My lab then carried the lead FDI forward into anti-HIV testing in the SHIV SF162P3 macaque model of HIV transmission. To push the limits of the product to prevent SHIV infection, we used an enhanced susceptibility model in which macaques are first treated with depot medroxyprogesterone acetate (DMPA). DMPA thins the vaginal epithelium and increases macaques’ susceptibility to vaginal SHIV infection . Concurrent with high susceptibility, ten of ten macaques vaginally challenged four hours after FDI insertion became infected with SHIV in the presence of the placebo (CG only) FDI. In contrast, only two of ten macaques challenged in the presence of the GRFT/CG FDI became infected. No difference in these animals’ viral loads compared to the controls was noted. Upon checking whether the two transmissions in presence of GRFT were due to selection of a unique viral variant in the inoculum with reduced GRFT sensitivity, we could find no evidence of GRFT-dependent selection. While GRFT has been shown to have an excellent resistance profile , additional work on selection and resistance will be needed with more animals and more sequence data.
The highly significant protection from vaginal SHIV transmission in a high susceptibility macaque model combined with highly significant protection from HSV and HPV indicated high promise for the GRFT/CG FDI as a clinical product. We decided to probe GRFT’s safety even further to enable phase 1 clinical testing of GRFT/CG, first as a vaginal gel and then as an FDI. The resulting safety/toxicology data, also contained within the Nature Communications manuscript, are confirmatory. The gel trial is underway (NCT02875119), and we are currently planning and seeking funding for phase 1 testing of the FDI.
We know that women want and need choices for contraception. Why wouldn’t they want choices in their HIV and STI prevention toolbox? The GRFT/CG FDI is one more step towards stemming the HIV pandemic by keeping women’s preferences and lifestyles in the picture.
This work was made possible by the generous support of the American people through the President’s Emergency Plan for AIDS Relief (PEPFAR) and United States Agency for International Development (USAID) via Cooperative Agreement AID-OAA-A-14-00009. The contents of this post and the associated article are the sole responsibility of the Population Council and do not necessarily reflect the views of USAID or the United States Government.
The Population Council conducts research and delivers solutions that improve lives around the world. Big ideas supported by evidence: It’s our model for global change.
1. Baeten, J.M., et al., Use of a Vaginal Ring Containing Dapivirine for HIV-1 Prevention in Women. N Engl J Med, 2016. 375(22): p. 2121-2132.
2. Marrazzo, J.M., et al., Tenofovir-based preexposure prophylaxis for HIV infection among African women. N Engl J Med, 2015. 372(6): p. 509-18.
3. Van Damme, L., et al., Preexposure prophylaxis for HIV infection among African women. N Engl J Med, 2012. 367(5): p. 411-22.
4. Kashuba, A.D., et al., Genital Tenofovir Concentrations Correlate With Protection Against HIV Infection in the CAPRISA 004 Trial: Importance of Adherence for Microbicide Effectiveness. J Acquir Immune Defic Syndr, 2015. 69(3): p. 264-9.
5. Mensch, B.S., A. van der Straten, and L.L. Katzen, Acceptability in microbicide and PrEP trials: current status and a reconceptualization. Curr Opin HIV AIDS, 2012. 7(6): p. 534-41.
6. Fernandez Romero, J.A., et al., Multipurpose prevention technologies: the future of HIV and STI prevention. Trends Microbiol, 2015. 23(7): p. 429-36.
7. Houlihan, C.F., et al., Human papillomavirus infection and increased risk of HIV acquisition. A systematic review and meta-analysis. AIDS, 2012. 26(17): p. 2211-22.
8. Looker, K.J., et al., Effect of HSV-2 infection on subsequent HIV acquisition: an updated systematic review and meta-analysis. Lancet Infect Dis, 2017. 17(12): p. 1303-1316.
9. Schelar, E., et al., Multipurpose prevention technologies for sexual and reproductive health: mapping global needs for introduction of new preventive products. Contraception, 2016. 93(1): p. 32-43.
10. Van de Perre, P., et al., Herpes simplex virus and HIV-1: deciphering viral synergy. Lancet Infect Dis, 2008. 8(8): p. 490-7.
11. Whitham, H.K., et al., A Comparison of the Natural History of HPV Infection and Cervical Abnormalities among HIV-Positive and HIV-Negative Women in Senegal, Africa. Cancer Epidemiol Biomarkers Prev, 2017. 26(6): p. 886-894.
12. Romano, J.W., et al., Non-specific microbicide product development: then and now. Curr HIV Res, 2012. 10(1): p. 9-18.
13. Kilmarx, P.H., et al., A randomized, placebo-controlled trial to assess the safety and acceptability of use of carraguard vaginal gel by heterosexual couples in Thailand. Sex Transm Dis, 2008. 35(3): p. 226-32.
14. Skoler-Karpoff, S., et al., Efficacy of Carraguard for prevention of HIV infection in women in South Africa: a randomised, double-blind, placebo-controlled trial. Lancet, 2008. 372(9654): p. 1977-87.
15. Buck, C.B., et al., Carrageenan is a potent inhibitor of papillomavirus infection. PLoS Pathog, 2006. 2(7): p. e69.
16. Novetsky, A.P., et al., In vitro inhibition of human papillomavirus following use of a carrageenan-containing vaginal gel. Gynecol Oncol, 2016. 143(2): p. 313-318.
17. Roberts, J.N., et al., Genital transmission of HPV in a mouse model is potentiated by nonoxynol-9 and inhibited by carrageenan. Nat Med, 2007. 13(7): p. 857-61.
18. Roberts, J.N., et al., Effect of Pap smear collection and carrageenan on cervicovaginal human papillomavirus-16 infection in a rhesus macaque model. J Natl Cancer Inst, 2011. 103(9): p. 737-43.
19. Rodriguez, A., et al., In vitro and in vivo evaluation of two carrageenan-based formulations to prevent HPV acquisition. Antiviral Res, 2014.
20. Zacharopoulos, V.R. and D.M. Phillips, Vaginal formulations of carrageenan protect mice from herpes simplex virus infection. Clin Diagn Lab Immunol, 1997. 4(4): p. 465-8.
21. Levendosky, K., et al., Griffithsin and Carrageenan Combination To Target Herpes Simplex Virus 2 and Human Papillomavirus. Antimicrob Agents Chemother, 2015. 59(12): p. 7290-8.
22. Fernandez-Romero, J.A., et al., Zinc acetate/carrageenan gels exhibit potent activity in vivo against high-dose herpes simplex virus 2 vaginal and rectal challenge. Antimicrob Agents Chemother, 2012. 56(1): p. 358-68.
23. Fernandez-Romero, J.A., et al., Carrageenan/MIV-150 (PC-815), a combination microbicide. Sex Transm Dis, 2007. 34(1): p. 9-14.
24. Crostarosa, F., et al., A macaque model to study vaginal HSV-2/immunodeficiency virus co-infection and the impact of HSV-2 on microbicide efficacy. PLoS One, 2009. 4(11): p. e8060.
25. Kenney, J., et al., An antiretroviral/zinc combination gel provides 24 hours of complete protection against vaginal SHIV infection in macaques. PLoS One, 2011. 6(1): p. e15835.
26. Kenney, J., et al., 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(11): p. 1476-84.
27. Singer, R., et al., An intravaginal ring that releases the NNRTI MIV-150 reduces SHIV transmission in macaques. Sci Transl Med, 2012. 4(150): p. 150ra123.
28. Kizima, L., et al., A potent combination microbicide that targets SHIV-RT, HSV-2 and HPV. PLoS One, 2014. 9(4): p. e94547.
29. Ouattara, L.A., et al., MIV-150-containing intravaginal rings protect macaque vaginal explants against SHIV-RT infection. Antimicrob Agents Chemother, 2014. 58(5): p. 2841-8.
30. Barnable, P., et al., 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(7): p. 3829-37.
31. Calenda, G., et al., MZC Gel Inhibits SHIV-RT and HSV-2 in Macaque Vaginal Mucosa and SHIV-RT in Rectal Mucosa. J Acquir Immune Defic Syndr, 2017. 74(3): p. e67-e74.
32. Derby, N., et al., An intravaginal ring that releases three antiviral agents and a contraceptive blocks SHIV-RT infection, reduces HSV-2 shedding, and suppresses hormonal cycling in rhesus macaques. Drug Deliv Transl Res, 2017.
33. Patel, S.K. and L.C. Rohan, On-demand microbicide products: design matters. Drug Deliv Transl Res, 2017.
34. O'Keefe, B.R., et al., Scaleable manufacture of HIV-1 entry inhibitor griffithsin and validation of its safety and efficacy as a topical microbicide component. Proc Natl Acad Sci U S A, 2009. 106(15): p. 6099-104.
35. Huskens, D., et al., Safety concerns for the potential use of cyanovirin-N as a microbicidal anti-HIV agent. Int J Biochem Cell Biol, 2008. 40(12): p. 2802-14.
36. Kouokam, J.C., et al., Investigation of griffithsin's interactions with human cells confirms its outstanding safety and efficacy profile as a microbicide candidate. PLoS One, 2011. 6(8): p. e22635.
37. Nixon, B., et al., Griffithsin protects mice from genital herpes by preventing cell-to-cell spread. J Virol, 2013. 87(11): p. 6257-69.
38. Lal, M., et al., Development of a vaginal fast-dissolving insert combining griffithsin and carrageenan for potential use against sexually transmitted infections. J Pharm Sci, 2018. S0022-3549(18): p. 30331-9.
39. Marx, P.A., et al., Progesterone implants enhance SIV vaginal transmission and early virus load. Nat Med, 1996. 2(10): p. 1084-9.
40. Alexandre, K.B., et al., Mechanisms of HIV-1 subtype C resistance to GRFT, CV-N and SVN. Virology, 2013. 446(1-2): p. 66-76.