Tenofovir Douche as HIV Preexposure Prophylaxis for Receptive Anal Intercourse: Safety, Acceptability, Pharmacokinetics, and Pharmacodynamics (DREAM 01).

BACKGROUND: Despite highly effective HIV preexposure prophylaxis (PrEP) options, no options provide on-demand, nonsystemic, behaviorally congruent PrEP that many desire. A tenofovir-medicated rectal douche before receptive anal intercourse may provide this option. METHODS: Three tenofovir rectal douches-220 mg iso-osmolar product A, 660 mg iso-osmolar product B, and 660 mg hypo-osmolar product C-were studied in 21 HIV-negative men who have sex with men. We sampled blood and colorectal tissue to assess safety, acceptability, pharmacokinetics, and pharmacodynamics. RESULTS: The douches had high acceptability without toxicity. Median plasma tenofovir peak concentrations for all products were several-fold below trough concentrations associated with oral tenofovir disoproxil fumarate (TDF). Median colon tissue mucosal mononuclear cell (MMC) tenofovir-diphosphate concentrations exceeded target concentrations from 1 hour through 3 to 7 days after dosing. For 6-7 days after a single product C dose, MMC tenofovir-diphosphate exceeded concentrations expected with steady-state oral TDF 300 mg on-demand 2-1-1 dosing. Compared to predrug baseline, HIV replication after ex vivo colon tissue HIV challenge demonstrated a concentration-response relationship with 1.9 log10 maximal effect. CONCLUSIONS: All 3 tenofovir douches achieved tissue tenofovir-diphosphate concentrations and colorectal antiviral effect exceeding oral TDF and with lower systemic tenofovir. Tenofovir douches may provide a single-dose, on-demand, behaviorally congruent PrEP option, and warrant continued development. Clinical Trials Registration . NCT02750540.

Validation and implementation of an ultrasensitive liquid chromatographic-tandem mass spectrometric (LC-MS/MS) assay for dapivirine quantitation in breast milk.

BACKGROUND: The non-nucleoside reverse transcriptase inhibitor dapivirine has been evaluated as a topical microbicidal agent to prevent HIV-1 acquisition. Several clinical trials have evaluated the pharmacokinetics of dapivirine when administered as a 25-mg intravaginal ring. Recent studies have focused on the distribution of dapivirine into breast milk. Drug distribution during lactation and breastfeeding can have implications in terms of infant drug exposure. Thus, sensitive bioanalytical tools are required to characterize the pharmacokinetics of dapivirine in breast milk. METHODS: Whole breast milk was spiked with dapivirine and internal standard. Lipid content was disrupted via pre-treatment with n-hexane, and supernatants were subjected to solid phase extraction. Extracted materials were subjected to liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis. Separation occurred using a Waters BEH C8, 50 × 2.1 mm UPLC column with a 1.7 µm particle size and dapivirine was detected on an API 5000 mass analyzer. Methods were validated in accordance with FDA Bioanalytical Method Validation recommendations. RESULTS: The analytical method was optimized for dapivirine extraction from breast milk. The analytical measuring range of the assay was 10-1000 pg/mL. Calibration curves were generated via weighted linear regression of standards. Intra- and inter-assay precision and accuracy studies demonstrated %CVs ≤ 14.6% and %DEVs ≤ ±12.7%. Stability and matrix effects studies were also conducted and deemed acceptable. The method was applied to a previously reported phase 1 clinical trial and demonstrated appropriate performance in the quantitation of dapivirine in breast milk samples from lactating women. CONCLUSIONS: An ultrasensitive LC-MS/MS assay has been developed and validated for the quantitation of dapivirine in breast milk. The described method meets validation acceptance criteria and has been applied to a phase 1 clinical trial.

2-Hydroxypropyl-ß-cyclodextrin-enhanced pharmacokinetics of cabotegravir from a nanofluidic implant for HIV pre-exposure prophylaxis.

Preexposure prophylaxis (PrEP) with antiretrovirals (ARV) can prevent human immunodeficiency virus (HIV) transmission, but its efficacy is highly dependent on strict patient adherence to daily dosing regimen. Long-acting (LA) ARV formulations or delivery systems that reduce dosing frequency may increase adherence and thus PrEP efficacy. While cabotegravir (CAB) long-acting injectable (CAB LA), an integrase strand transfer inhibitor (INSTI), reduces dosing frequency to bimonthly injections, variable pharmacokinetics (PK) between patients and various adverse reactions necessitate improvement in delivery methods. Here we developed a subcutaneously implantable nanofluidic device for the sustained delivery of CAB formulated with 2-hydroxypropyl-ß-cyclodextrin (ßCAB) and examined the pharmacokinetics (PK) in Sprague-Dawley rats for 3 months in comparison to CAB. Our study demonstrated ßCAB treatment group maintained clinically-relevant plasma CAB concentrations 2 times above the protein-adjusted concentration that inhibits viral replication by 90% (2 × PA-IC90) and drug penetration into tissues relevant to HIV-1 transmission. Further, we successfully fitted plasma CAB concentrations into a PK model (R2 = 0.9999) and determined CAB apparent elimination half-life of 47 days. Overall, our data shows the potential of sustained release of ßCAB via a nanofluidic implant for long-term PrEP delivery, warranting further investigation for efficacy against HIV infections.

Short Communication: Specimen Processing Impacts Tissue Tenofovir Pharmacokinetic Measurements.

Antiretroviral drug concentrations at sites of HIV exposure are important drivers that influence the development of HIV pre-exposure chemoprophylaxis strategies and regimens. We assessed the effect of collection method-in the presence or absence of tissue culture medium-on tenofovir (TFV) and tenofovir diphosphate (TFV-DP) concentrations in colonic biopsies. We find significant baseline interbiopsy variation in TFV (38% CV) and TFV-DP (33% CV) concentrations. Incubation in medium leads to a fluid absorption-driven twofold increase in tissue weight with a concomitant 75% decrease in weight-adjusted tissue TFV concentrations 120 min post-incubation. In contrast, adjusted TFV-DP concentrations decrease by only 25% during the same period, with this difference not achieving statistical significance. Although colonic biopsies should be collected in the absence of medium for accurate TFV concentrations, the presence of medium does not significantly impact TFV-DP-dependent pharmacokinetic or pharmacodynamic assays. Appropriate assessment of tissue drug concentrations should account for biopsy collection method and drug mechanism of action.

HIV-1-Neutralizing IgA Detected in Genital Secretions of Highly HIV-1-Exposed Seronegative Women on Oral Preexposure Prophylaxis.

Although nonhuman primate studies have shown that simian immunodeficiency virus/simian-human immunodeficiency virus (SIV/SHIV) exposure during preexposure prophylaxis (PrEP) with oral tenofovir can induce SIV immunity without productive infection, this has not been documented in humans. We evaluated cervicovaginal IgA in Partners PrEP Study participants using a subtype C primary isolate and found that women on PrEP had IgA with higher average human immunodeficiency virus type 1 (HIV-1)-neutralizing magnitude than women on placebo (33% versus 7%; P = 0.008). Using a cutoff of ≥90% HIV-1 neutralization, 19% of women on-PrEP had HIV-1-neutralizing IgA compared to 0% of women on placebo (P = 0.09). We also estimated HIV-1 exposure and found that the proportion of women with HIV-1-neutralizing IgA was associated with the level of HIV-1 exposure (P = 0.04). Taken together, our data suggest that PrEP and high levels of exposure to HIV may each enhance mucosal HIV-1-specific humoral immune responses in sexually exposed but HIV-1-uninfected individuals. IMPORTANCE: Although there is not yet an effective HIV-1 vaccine, PrEP for at-risk HIV-1-uninfected individuals is a highly efficacious intervention to prevent HIV-1 acquisition and is currently being recommended by the CDC and WHO for all individuals at high risk of HIV-1 acquisition. We previously demonstrated that PrEP use does not enhance peripheral blood HIV-1-specific T-cell responses in HIV-exposed individuals. Here, we evaluate for cervicovaginal HIV-neutralizing IgA responses in genital mucosal secretions of HIV-exposed women, which is likely a more relevant site than peripheral blood for observation of potentially protective immune events occurring in response to sexual HIV-1 exposure for various periods. Furthermore, we assess for host response in the context of longitudinal quantification of HIV-1 exposure. We report that HIV-neutralizing IgA is significantly correlated with higher HIV-1 exposure and, furthermore, that there are more women with HIV-1-neutralizing IgA in the on-PrEP group than in the placebo group.

Rapid Quantification of Medroxyprogesterone Acetate (MPA) in Human Plasma by LC-MS/MS.

BACKGROUND: Medroxyprogesterone acetate (MPA) is a common contraceptive agent taken both orally and as a subcutaneous or intramuscular injection. Current LC-MS/MS methods for MPA quantification require large sample volumes and low-throughput analytical run times. Therefore, there are opportunities to improve upon existing methods for MPA quantification. METHODS: MPA was extracted from 600 µL plasma, evaporated to dryness, and the reconstituted solution was injected onto a Waters Acquity liquid chromatography (LC) system via an Agilent Zorbax Eclipse-Plus C18 2.1 × 50 mm (5.0 µm) column. MPA and its internal standard were monitored on a QTRAP® 5500 mass analyzer operated in positive ionization mode. The method was validated according to the Food and Drug Administration Bioanalytical Method Validation guidelines. RESULTS: The analytical measuring range of the assay was 200-10 000 pg/mL. QC samples prepared at the lower limit of quantification (LLOQ; 200 pg/mL) and low (600 pg/mL), mid (1750 pg/mL), and high (8500 pg/mL) levels showed interassay precision and accuracy ≤15.2% and ≤±9.6%, respectively. Stability-challenged samples yielded ≤15% from freshly prepared samples. Dilutional and matrix effects studies were also acceptable. The assay was also assessed in participants prescribed depot medroxyprogesterone acetate; observed concentrations were within the dynamic range of the assay. CONCLUSIONS: An LC-MS/MS method for the quantification of MPA in plasma has been developed and validated. The described method is sufficiently sensitive and robust to quantify MPA in plasma and meets the criteria to support clinical trials.

A Phase 1 Randomized, Blinded Comparison of the Pharmacokinetics and Colonic Distribution of Three Candidate Rectal Microbicide Formulations of Tenofovir 1% Gel with Simulated Unprotected Sex (CHARM-02).

CHARM-02 is a crossover, double-blind, randomized trial to compare the safety and pharmacokinetics of three rectally applied tenofovir 1% gel candidate rectal microbicides of varying osmolalities: vaginal formulation (VF) (3111 mOsmol/kg), the reduced glycerin vaginal formulation (RGVF) (836 mOsmol/kg), and an isoosmolal rectal-specific formulation (RF) (479 mOsmol/kg). Participants (n = 9) received a single, 4 ml, radiolabeled dose of each gel twice, once with and once without simulated unprotected receptive anal intercourse (RAI). The safety, plasma tenofovir pharmacokinetics, colonic small molecule permeability, and SPECT/CT imaging of lower gastrointestinal distribution of drug and virus surrogate were assessed. There were no Grade 3 or 4 adverse events reported for any of the products. Overall, there were more Grade 2 adverse events in the VF group compared to RF (p = 0.006) and RGVF (p = 0.048). In the absence of simulated unprotected RAI, VF had up to 3.8-fold greater systemic tenofovir exposure, 26- to 234-fold higher colonic permeability of the drug surrogate, and 1.5- to 2-fold greater proximal migration in the colonic lumen, when compared to RF and RGVF. Similar trends were observed with simulated unprotected RAI, but most did not reach statistical significance. SPECT analysis showed 86% (standard deviation 19%) of the drug surrogate colocalized with the virus surrogate in the colonic lumen. There were no significant differences between the RGVF and RF formulation, with the exception of a higher plasma tenofovir concentration of RGVF in the absence of simulated unprotected RAI. VF had the most adverse events, highest plasma tenofovir concentrations, greater mucosal permeability of the drug surrogate, and most proximal colonic luminal migration compared to RF and RGVF formulations. There were no major differences between RF and RGVF formulations. Simultaneous assessment of toxicity, systemic and luminal pharmacokinetics, and colocalization of drug and viral surrogates substantially informs rectal microbicide product development.