CROI 2019 Abstract eBook

Abstract eBook

Poster Abstracts

Methods: We reacted CAB with stearoyl chloride in anhydrous dimethylformamide using N,N-diisopropylethylamine base under argon. The created M2CAB ester was purified by silica column chromatography and characterized by 1 H-NMR and FTIR spectroscopy. Nanoparticles were produced by high pressure homogenization (NM2CAB). Human monocyte derived macrophages (MDM) were used as a biological platform to measure drug uptake and retention. Drug levels were quantitated in cell lysates by UPLC-TUV. After MDM treatment with 100 µM NM2CAB cells were challenged with HIV-1 ADA at a MOI of 0.1 at five day intervals for one month. Culture fluids were assayed for reverse transcriptase activity and cell-based HIV-1p24 antigens recorded by immunohistochemistry. Female NSG mice were injected with 45 mg/kg CAB equivalents of NCAB, NMCAB and NM2CAB (unmodified CAB, first and second generation prodrug nanoformulatios). Plasma was collected weekly after injection and CAB and prodrug levels were analyzed. Results: NM2CAB, NMCAB and CAB LAP (referred to as NCAB) uptake in MDM was 57, 44 and 2 nmol/10 6 cells over 24 hours. Only NM2CAB was retained in MDM (levels of 8 nmol/10 6 cells) at the end of one month. NM2CAB antiretroviral activity in MDM was observed over 30 days compared to 15 and 1 day for NMCAB and NCAB respectively. After a single 45 mg/kg CAB equivalent IM injection of NM2CAB in mice, plasma CAB levels were consistently 4 times PA-IC 90 for 4 months compared to 2.5 and 1 month for NMCAB and NCAB. Conclusion: The hydrophobicity and sustained slow hydrolysis of prodrug M2CAB facilitate NM2CAB to harness the injection site as a primary drug depot as well as macrophages and other tissues as secondary drug depots for months. This can potentially reduce frequent dosing and injection volume improving patient adherence to antiretroviral therapy.

488 LONG-ACTING EMTRICITABINE PRODRUGS PROVIDE PROTECTION FROM HIV INFECTION IN VIVO Paul Curley 1 , James J. Hobson 1 , Neill Liptrott 1 , Amer Al-Khouja 2 , David Meyers 2 , Caren Freel Meyers 2 , Charles W. Flexner 2 , Marco Siccardi 1 , Steve Rannard 1 , Larisa Y. Poluektova 3 , Andrew Owen 1 1 University of Liverpool, Liverpool, UK, 2 Johns Hopkins University, Baltimore, MD, USA, 3 University of Nebraska Medical Center, Omaha, NE, USA Background: Antiretroviral drugs are predominantly administered orally for both therapy and pre-exposure prophylaxis (PrEP). Despite ease of administration, oral delivery is prone to patient non-adherence exacerbated for some drugs by pill fatigue and gastrointestinal intolerance. By decreasing frequency of administration, long-acting injectable (LAI) medications are effective strategies to circumvent these issues. We report here a preclinical assessment of LAI semi-solid prodrug nanoparticle (SSPN) formulations of novel emtricitabine (FTC) prodrugs to prevent HIV infection. Methods: SSPNs of FTC carbamate/carbonate prodrugs were generated using a proprietary emulsion-templated freeze-drying technology. 2 lead formulations were tested for their ability to prevent HIV infection in NSG-cmah -/- mice humanised by CD34+ cell transplantation. Animals received 140 mg/kg FTC equivalent (SSPN 9 or 10) via 2 intramuscular injections vs an untreated control (n= 7-6 per group). At days 7 and 14 mice were challenged intraperitoneally with a 103 TCID50 dose of HIVADA. Animals were sacrificed at 28 days post infection. Plasma samples were taken for determination of viral load (VL). Tissue samples were collected for viral RNA and proteins detection via RT-PCR and immunohistology. Results: Mice treated with SSPN 9 and 10 demonstrated undetectable VL (700 copies/mL detection limit), and HIV RNA remained undetectable 28 days post infection in plasma, spleen, lung and liver in all animals for the 7 challenge. Following 14-day challenge, mice treated with SSPN 9 demonstrated undetectable HIV in plasma and all tissues. Mice treated with SSPN 10 demonstrated 2 mice had detectable plasma VL (4.77 x 10 3 copies/mL) and 3 mice showed presence of HIV RNA in plasma and proteins in spleen, lung and liver in day 28. HIV was detectable in all untreated animals. Conclusion: The data presented here demonstrate both formulations were 100% effective at preventing HIV infection 7 days post LAI administration. Following 14 days SSPN9 prevented HIV infection in 100% of mice while SSPN 10 prevented infection in 50% of mice. These data indicate great potential for delivering FTC via LAI and the approach may support LAI development for PrEP. Further studies will aim to optimise formulations to produce exposure beyond 14 days and to assess applications in therapy as part of a combination. 489 PRODRUGS EXTEND THE HALF LIFE AND POTENCY OF CABOTEGRAVIR Tanmay A. Kulkarni , Aditya N. Bade, Brady J. Sillman, Bhagya Dyavar Shetty, Melinda Wojtkiewicz, JoEllyn McMillan, Benson Edagwa, Howard E. Gendelman University of Nebraska Medical Center, Omaha, NE, USA Background: Prevention of new infections, reduction in transmission rates and management of chronic infection characterize once a month dosing of the current long acting cabotegravir (CAB). Previously we demonstrated that potency, bioavailability and tissue distribution of CAB can be improved up to 3-fold by myristoylation, increasing drug lipophilicity. This extended PA-IC 90 up to 3 months in Rhesus macaques after a single 45 mg/kg CAB equivalent intramuscular (IM) injection. We now report stearoylation of CAB (termed M2CAB) designed to reduce dosing frequency while improving viral reservoir targeting and drug activity.

Poster Abstracts

490 HIV REPLICATION AT <40C/ML FOR DTG+3TC VS DTG+TDF/FTC IN THE GEMINI 1 & 2 STUDIES Mark Underwood 1 , Rimgaile Urbaitye 2 , Choy Man 1 , Jörg Sievers 3 , Ruolan Wang 1 , Brian Wynne 1 , Allan-Raymond Tenorio 1 , Alexander Currie 2 , Keith Pappa 1 , Justin Koteff 1 , Martin Gartland 1 , Michael Aboud 3 1 ViiV Healthcare, Research Triangle Park, NC, USA, 2 GlaxoSmithKline, Uxbridge, UK, 3 ViiV Healthcare, Brentford, UK emtricitabine (DTG+TDF/FTC, 3DR) at Week 48 by FDA snapshot algorithm; 91% (655/716) in the 2DR group versus 93% (669/717) in the 3DR group achieved HIV-1 RNA <50c/mL. Abbott RealTime HIV-1 assay used in the studies measures viral load (VL) from 40c/mL to 10,000,000c/mL, and provides qualitative target detected (TD) or target not detected (TND) for VL<40c/mL. Clinical and subject management implications of more stringent low level VL data needs clarification. We assessed the proportion of participants with TND over time and by baseline (BL) VL for 2DR versus 3DR. Methods: Subjects were randomised 1:1 to treatment with 2DR or 3DR. The proportion of subjects with HIV-1 RNA <40 c/mL and TND status at Week 48 was analysed using a Cochran-Mantel-Haenszel test stratified by plasma HIV-1 RNA (≤100,000 vs >100,000 copies/mL) and CD4+ cell count (≤200 vs >200 cells/ mm3) at BL. Proportion of subjects with TND Status were summarised by Visit and at Week 48 by BL HIV-1 RNA Subgroup. Time to Plasma HIV-1 RNA <40 c/ Background: The GEMINI-1&2 studies in treatment-naïve adults with screening HIV-1 RNA ≤500,000c/mL showed dolutegravir+lamivudine (DTG+3TC, 2DR) was non-inferior to dolutegravir+tenofovir disoproxil/

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