Clinical, pharmacological, and qualitative characterization of drug-drug interactions in pregnant women initiating HIV therapy in Sub-Saharan Africa.

BACKGROUND: We investigated the impact of Drug-Drug Interactions (DDIs) on virologic control among HIV-positive pregnant women initiating antiretroviral therapy while identifying drivers for Traditional Medicine (TM) use and exploring the nature and extent of TM-related DDIs. METHODS: Employing a three-pronged approach, we examined DDIs arising from comedication, including TM, in ART. The DolPHIN-2 trial (NCT03249181) randomized 268 HIV-positive pregnant women in Uganda and South Africa to dolutegravir (DTG)-based (135) or efavirenz-based (133) regimens while systematically recording comedications and screening for DDIs. We used Cox regression models to compare time-to-virologic control between participants with and without DDIs. We conducted in-depth interviews and focus group discussions among 37 and 67 women with and without HIV, respectively, to explore reasons for TM use during pregnancy. Additionally, in-vitro and in-vivo studies evaluated the composition and impact of clay-based TM, mumbwa, on DTG plasma exposure. RESULTS: The baseline prevalence of DDIs was 67.2%, with TM use prevalent in 34% of participants, with mumbwa being the most frequent (76%, 69/91). There was no difference in virologic response between participants with and without DDIs. Fetal health and cultural norms were among the reasons cited for TM use. Analysis of mumbwa rods confirmed significant amounts of aluminium (8.4%-13.9%) and iron (4%-6%). In Balb-C mice, coadministration of mumbwa led to a reduction in DTG exposure observed in the AUC0-24 (-21%; P = 0.0271) and C24 (-53%; P = 0.0028). CONCLUSIONS: The widespread use of clay-based TM may compromise HIV treatment, necessitating medication screening and counselling to manage DDIs in pregnant women.

Tenofovir, emtricitabine, lamivudine and dolutegravir concentrations in plasma and urine following drug intake cessation in a randomized controlled directly observed pharmacokinetic trial to aid point-of-care testing.

BACKGROUND: Poor adherence to ART and pre-exposure prophylaxis (PrEP) can impact patient and public health. Point-of-care testing (POCT) may aid monitoring and adherence interventions. OBJECTIVES: We report the pharmacokinetics of tenofovir [dosed as tenofovir disoproxil (TDF) and tenofovir alafenamide (TAF)], emtricitabine (FTC), lamivudine (3TC) and dolutegravir (DTG) in plasma and urine following drug cessation to evaluate adherence targets in urine for POCT. METHODS: Subjects were randomized (1:1) to receive DTG/FTC/TAF or DTG/3TC/TDF for 15 days. Plasma and spot urine were collected on Day 15 (0-336 h post final dose). Drug concentrations were quantified using LC-MS, and non-linear mixed-effects models applied to determine drug disposition between matrices and relationship with relevant plasma [dolutegravir protein-adjusted 90% inhibitory concentration (PA-IC90 = 64 ng/mL) and minimum effective concentration (MEC = 324 ng/mL)] and urinary thresholds [tenofovir disoproxil fumarate 1500 ng/mL]. RESULTS: Of 30 individuals enrolled, 29 were included (72% female at birth, 90% Caucasian). Median (range) predicted time to plasma dolutegravir PA-IC90 and MEC were 83.5 (41.0-152) and 49.0 h (23.7-78.9), corresponding to geometric mean (90%) urine concentrations of 5.42 (4.37-6.46) and 27.4 ng/mL (22.1-32.7). Tenofovir in urine reached 1500 ng/mL by 101 h (58.6-205) with an equivalent plasma concentration of 6.20 ng/mL (4.21-8.18). CONCLUSIONS: These data support use of a urinary tenofovir threshold of <1500 ng/mL (tenofovir disoproxil fumarate-based regimens) as a marker of three or more missed doses for a POCT platform. However, due to low dolutegravir concentrations in urine, POCT would be limited to a readout of recent dolutegravir intake (one missed dose).

A novel LC-MS/MS method for the determination of favipiravir ribofuranosyl-5'-triphosphate (T-705-RTP) in human peripheral mononuclear cells.

Favipiravir is a broad-spectrum antiviral that is metabolised intracellularly into the active form, favipiravir ribofuranosyl-5'-triphosphate (F-RTP). Measurement of the intracellular concentration of F-RTP in mononuclear cells is a crucial step to characterising the pharmacokinetics of F-RTP and to enable more appropriate dose selection for the treatment of COVID-19 and emerging infectious diseases. The described method was validated over the range 24 - 2280 pmol/sample. Peripheral blood mononuclear cells (PBMCs) were isolated from whole blood and lysed using methanol-water (70:30, v/v) before cellular components were precipitated with acetonitrile and the supernatant further cleaned by weak anion exchange solid phase extraction. The method was found to be both precise and accurate and was successfully utilised to analyse F-RTP concentrations in patient samples collected as part of the AGILE CST-6 clinical trial.

A randomized clinical trial of on-demand oral pre-exposure prophylaxis does not modulate lymphoid/myeloid HIV target cell density in the foreskin.

OBJECTIVES: As topical pre-exposure prophylaxis (PrEP) has been shown to cause immune modulation in rectal or cervical tissue, our aim was to examine the impact of oral PrEP on lymphoid and myeloid changes in the foreskin in response to dosing and timing of drug administration. DESIGN: HIV-negative male individuals ( n  = 144) were recruited in South Africa and Uganda into an open-label randomized controlled trial in a 1 : 1 : 1 : 1 : 1 : 1 : 1 : 1 : 1 ratio to control arm (with no PrEP) or one of eight arms receiving emtricitabine-tenofovir disoproxil fumarate (F/TDF) or emtricitabine-tenofovir alafenamide (F/TAF) at one of two different doses, 5 or 21 h before undergoing voluntary medical male circumcision (VMMC). METHODS: After dorsal-slit circumcision, foreskin tissue sections were embedded into Optimal Cutting Temperature media and analysed, blinded to trial allocation, to determine numbers of CD4 + CCR5 + , CD1a + cells and claudin-1 expression. Cell densities were correlated with tissue-bound drug metabolites and p24 production after ex-vivo foreskin challenge with HIV-1 bal . RESULTS: There was no significant difference in CD4 + CCR5 + or CD1a + cell numbers in foreskins between treatment arms compared with the control arm. Claudin-1 expression was 34% higher ( P  = 0.003) in foreskin tissue from participants receiving PrEP relative to controls, but was no longer statistically significant after controlling for multiple comparisons. There was neither correlation of CD4 + CCR5 + , CD1a + cell numbers, or claudin-1 expression with tissue-bound drug metabolites, nor with p24 production after ex-vivo viral challenge. CONCLUSION: Oral doses and timing of on-demand PrEP and in-situ drug metabolite levels in tissue have no effect on numbers or anatomical location of lymphoid or myeloid HIV target cells in foreskin tissue.

Dose finding study for on-demand HIV pre-exposure prophylaxis for insertive sex in sub-Saharan Africa: results from the CHAPS open label randomised controlled trial.

BACKGROUND: The efficacy of on-demand HIV pre-exposure prophylaxis (PrEP) for men in sub-Saharan Africa has not been evaluated, and the on-demand PrEP dosing requirement for insertive sex remains unknown. METHODS: HIV-negative males 13-24 years, requesting voluntary medical male circumcision (VMMC), were enrolled into an open-label randomised controlled trial (NCT03986970), and randomised 1:1:1:1:1:1:1:1:1 to control arm or one of eight arms receiving emtricitabine-tenofovir disoproxil fumarate (F/TDF) or emtricitabine-tenofovir alafenamide (F/TAF) over one or two days, and circumcised 5 or 21 h thereafter. The primary outcome was foreskin p24 concentrations following ex vivo HIV-1BaL challenge. Secondary outcomes included peripheral blood mononuclear cell (PBMC) p24 concentration, and drug concentrations in foreskin tissue, PBMCs, plasma and foreskin CD4+/CD4-cells. In the control arm, post-exposure prophylaxis (PEP) activity of non-formulated tenofovir-emtricitabine (TFV-FTC) or TAF-FTC was assessed with ex vivo dosing 1, 24, 48 or 72 h post-HIV-1 challenge. FINDINGS: 144 participants were analysed. PrEP with F/TDF or F/TAF prevented ex vivo infection of foreskins and PBMCs both 5 and 21 h after PrEP dosing. There was no difference between F/TDF and F/TAF (p24day15 geometric mean ratio 1.06, 95% confidence interval: 0.65-1.74). Additional ex vivo dosing did not further increase inhibition. In the control arm, PEP ex vivo dosing was effective up to 48 post-exposure diminishing thereafter, with TAF-FTC showing prolonged protection compared to TFV-FTC. Participants receiving F/TAF had higher TFV-DP concentrations in foreskin tissue and PBMCs compared with F/TDF, irrespective of dose and sampling interval; but F/TAF did not confer preferential TFV-DP distribution into foreskin HIV target cells. FTC-TP concentrations with both drug regimens were equivalent and ∼1 log higher than TFV-DP in foreskin. INTERPRETATION: A double dose of either F/TDF or F/TAF given once either 5 or 21 h before ex vivo HIV-challenge provided protection across foreskin tissue. Further clinical evaluation of pre-coital PrEP for insertive sex is warranted. FUNDING: EDCTP2, Gilead Sciences, Vetenskapsrådet.

Application of novel plasma separation filter cards for quantification of nucleoside/nucleotide reverse transcriptase inhibitor di/triphosphates in dried blood spots using LC-MS.

Background: A rapid and sensitive LC-MS method has been developed and validated for the quantification of nucleoside di/triphosphates using a novel plasma separation card (HemaSep). Materials & methods: Cards were spotted with whole blood and stored at -80°C. Metabolites were extracted using 70:30 MeOH:20% formic acid, followed by weak anion exchange SPE and eluted using a Biobasic-AX column. Quantification was performed using a triple quadrupole mass spectrometer with a calibration range of 1.25-250 pmol/sample. Results: The recovery of metabolites was high (>93%). Precision and accuracy were acceptable and metabolites remained stable on the card after 29 days (stored at ambient temperature). Conclusion: HemaSep dried blood spots are a useful microsampling tool and offer an alternative to liquid plasma as they maintain stability over time.

Development and validation of an LC-MS/MS method for quantification of favipiravir in human plasma.

Favipiravir (FVP) is a broad-spectrum antiviral that selectively inhibits viral RNA-dependent RNA polymerase, first trialled for the treatment of influenza infection. It has been shown to be effective against a number of RNA virus families including arenaviruses, flaviviruses and enteroviruses. Most recently, FVP has been investigated as a potential therapeutic for severe acute respiratory syndrome coronavirus 2 infection. A liquid chromatography tandem mass spectrometry method for the quantification of FVP in human plasma has been developed and validated for use in clinical trials investigating favipiravir as treatment for coronavirus disease-2019. Samples were extracted by protein precipitation using acetonitrile, using 13C, 15N- Favipiravir as internal standard. Elution was performed on a Synergi Polar-RP 150 × 2.1 mm 4 µm column using a gradient mobile phase programme consisting of 0.2% formic acid in water and 0.2% formic acid in methanol. The assay was validated over the range 500-50,000 ng/mL; this method was found to be precise and accurate and recovery of FVP from the matrix was high. Stability experiments confirmed and expanded on the known stability of FVP, including under heat treatment and for a period of 10 months at - 80 °C.

Undeclared pre-exposure or post-exposure prophylaxis (PrEP/PEP) use among syphilis-positive blood donors, England, 2020 to 2021.

An individualised blood donor selection policy was implemented in the United Kingdom from summer 2021. We have investigated the impact of this policy by comparing the extent of undeclared use of HIV pre-exposure or post-exposure prophylaxis (PrEP/PEP) before and after this change. The rate of PrEP usage in syphilis-positive male blood donors has not changed since individualised donor assessment was implemented but provides continuing evidence of undisclosed PrEP use which may be associated with current or past higher-risk sexual behaviours.

Short-term oral pre-exposure prophylaxis against HIV-1 modulates the transcriptome of foreskin tissue in young men in Africa.

Whilst short-term oral pre-exposure prophylaxis (PrEP) with antiretroviral drugs in men who have sex with men has shown protection against HIV-1 infection, the impact of this regimen on the in vivo foreskin transcriptome is unknown. We collected foreskin tissue after voluntary medical male circumcision from 144 young men (72 from Uganda and 72 from South Africa) randomized to one to two doses of either oral tenofovir (TFV) disoproxil fumarate (FTC-TDF) or tenofovir alafenamide (FTC-TAF) or no drug (untreated controls). This novel approach allowed us to examine the impact of short-term oral PrEP on transcriptome of the male genital tract. A single dose of FTC-TDF did not affect the foreskin transcriptome in relation to control arm, however one dose of FTC-TAF induced upregulation of four genes AKAP8, KIAA0141, HSCB and METTL17. Following two doses of either FTC-TDF or FTC-TAF, there was an increase in 34 differentially expressed genes for FTC-TDF and 15 for FTC-TAF, with nine DEGs in common: KIAA0141, SAFB2, CACTIN, FXR2, AKAP8, HSCB, CLNS1A, DDX27 and DCAF15. Functional analysis of differentially expressed genes revealed modulation of biological processes related to mitochondrial stress (KIAA0141, HSCB and METTL17), anti-viral and anti-inflammatory pathways (CACTIN and AKAP8). Our results show that short-course on-demand oral PrEP in men modulates genes in foreskin tissue which are likely unfavorable to HIV acquisition and replication. We also describe an upregulated expression of genes involved in diverse mitochondria biology which may potentially result in worsened mitochondria-related. These results warrant further studies to assess the role of short-course and prolonged oral PrEP on biological processes of the foreskin mucosa.

Mobilization of systemic CCL4 following HIV pre-exposure prophylaxis in young men in Africa.

HIV-1 pre-exposure prophylaxis (PrEP) relies on inhibition of HIV-1 replication steps. To understand how PrEP modulates the immunological environment, we derived the plasma proteomic profile of men receiving emtricitabine-tenofovir (FTC-TDF) or emtricitabine-tenofovir alafenamide (FTC-TAF) during the CHAPS trial in South Africa and Uganda (NCT03986970). The CHAPS trial randomized 144 participants to one control and 8 PrEP arms, differing by drug type, number of PrEP doses and timing from final PrEP dose to sampling. Blood was collected pre- and post-PrEP. The inflammatory profile of plasma samples was analyzed using Olink (N=92 proteins) and Luminex (N=33) and associated with plasma drug concentrations using mass spectrometry. The proteins whose levels changed most significantly from pre- to post-PrEP were CCL4, CCL3 and TNF-α; CCL4 was the key discriminator between pre- and post-PrEP samples. CCL4 and CCL3 levels were significantly increased in post-PrEP samples compared to control specimens. CCL4 was significantly correlated with FTC drug levels in plasma. Production of inflammatory chemokines CCL4 and CCL3 in response to short-term PrEP indicates the mobilization of ligands which potentially block virus attachment to CCR5 HIV-1 co-receptor. The significant correlation between CCL4 and FTC levels suggests that CCL4 increase is modulated as an inflammatory response to PrEP.

Pre-Clinical Evaluation of Tenofovir and Tenofovir Alafenamide for HIV-1 Pre-Exposure Prophylaxis in Foreskin Tissue.

BACKGROUND: HIV-1 pre-exposure prophylaxis (PrEP) has focused predominantly on protective efficacy in receptive sex, with limited research on the dosing requirements for insertive sex. We pre-clinically assessed the ex vivo pharmacokinetic-pharmacodynamic (PK-PD) profile of tenofovir (TFV) and tenofovir alafenamide (TAF) in foreskin tissue. METHODS: Inner and outer foreskin explants were exposed to serial dilutions of TFV or TAF prior to addition of HIV-1BaL at a high (HVT) or a low viral titer (LVT). Infection was assessed by measurement of p24 in foreskin culture supernatants. TFV, TAF and TFV-diphosphate (TFV-DP) concentrations were measured in tissues, culture supernatants and dosing and washing solutions. RESULTS: Dose-response curves were obtained for both drugs, with greater potency observed against LVT. Inhibitory equivalency mimicking oral dosing was defined between 1 mg/mL of TFV and 15 µg/mL of TAF against HVT challenge. Concentrations of TFV-DP in foreskin explants were approximately six-fold higher after ex vivo dosing with TAF than with TFV. Statistically significant negative linear correlations were observed between explant levels of TFV or TFV-DP and p24 concentrations following HVT. CONCLUSIONS: Pre-clinical evaluation of TAF in foreskin explants revealed greater potency than TFV against penile HIV transmission. Clinical evaluation is underway to support this finding.

TRUE-1: Trial of Repurposed Unithiol for snakebite Envenoming phase 1 (safety, tolerability, pharmacokinetics and pharmacodynamics in healthy Kenyan adults).

Background: Snakebites affect over 5 million people each year, and over 100,000 per year die as a result. The only available treatment is antivenom, which has many shortcomings including high cost, intravenous administration, and high risk of adverse events. One of the most abundant and harmful components of viper venoms are the zinc-dependent snake venom metalloproteinases (SVMPs). Unithiol is a chelating agent which is routinely used to treat heavy metal poisoning. In vivo experiments in small animal models have demonstrated that unithiol can prevent local tissue damage and death caused by a certain viper species. This phase I clinical trial will assess the safety of ascending doses of unithiol with a view for repurposing for snakebite indication. Methods: This open label, single agent, phase I clinical trial of a repurposed drug has a primary objective to evaluate the safety of escalating doses of unithiol, and a secondary objective to describe its pharmacokinetics. In total, 64 healthy Kenyan volunteers from Kilifi County will be dosed in consecutive groups of eight, with dose escalation decisions dependent on review of safety data by an independent data safety monitoring board. Four groups will receive ascending single oral doses, two will receive multiple oral doses, and two will receive single intravenous doses. Follow-up will be for 6-months and includes full adverse event reporting. Pharmacokinetic analysis will define the Cmax, Tmax, half-life and renal elimination. Conclusions: This clinical trial will assess the safety and tolerability of a promising oral therapeutic in a relevant setting where snakebites are prevalent. Unithiol is likely to be safer than antivenom, is easier to manufacture, has activity against diverse snake species, and can be administered orally, and thus shows promise for repurposing for tropical snakebite. Pan African Clinical Trials Registry: PACTR202103718625048 (3/3/2021).

Removal of doravirine by haemodialysis in people living with HIV with end-stage renal disease.

OBJECTIVES: To evaluate the effect of haemodialysis on doravirine concentrations in people living with HIV (PLWH) undergoing routine haemodialysis. METHODS: An exploratory clinical trial that included PLWH undergoing intermittent haemodialysis was undertaken. After enrolment (day 1), doravirine 100 mg once daily was added to stable combined ART for 5 days. On day 6, blood samples were collected from each participant at the beginning and at the end of a dialysis session. Additionally, paired samples of blood entering ('in') and leaving ('out') the dialyser and the resulting dialysate were collected during the dialysis session to evaluate drug removal during dialysis. Doravirine concentrations in plasma and in the dialysate were determined by LC-MS/MS. The ratio of doravirine concentrations in plasma after/before the haemodialysis session and the haemodialysis extraction coefficient were calculated for each participant. The study was registered at https://www.clinicaltrials.gov (NCT04689737). RESULTS: Eight participants (six male) were included. The median (range) age and BMI were 49.5 (28-67) years and 23.6 (17.9-34.2) kg/m2, respectively. The doravirine dialysis extraction ratio was 34.3% (25.8%-41.4%). The ratio of doravirine concentrations in plasma after/before the haemodialysis session was 0.8 (0.6-1.0). At the end of the haemodialysis session (time post-dose 20.8-27.3 h), doravirine concentrations in plasma were 785 (101-1851) ng/mL. CONCLUSIONS: Despite moderate removal of doravirine by haemodialysis, trough doravirine concentrations in plasma after the haemodialysis sessions remained in excess of the protein-binding-adjusted EC50 (5 ng/mL). Doravirine dosage adjustments are unnecessary in PLWH undergoing intermittent haemodialysis.

Pharmacokinetics of ß-d-N4-Hydroxycytidine, the Parent Nucleoside of Prodrug Molnupiravir, in Nonplasma Compartments of Patients With Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

ß-d-N4-hydroxycytidine (NHC), the parent nucleoside of molnupiravir, a COVID-19 antiviral, was quantified at SARS-CoV-2 transmission sites in 12 patients enrolled in AGILE Candidate-Specific Trial-2. Saliva, nasal, and tear NHC concentrations were 3%, 21%, and 22% that of plasma. Saliva and nasal NHC were significantly correlated with plasma (P < .0001). Clinical Trials Registration. NCT04746183.

Evidence of HIV pre-exposure or post-exposure prophylaxis (PrEP/PEP) among blood donors: a pilot study, England June 2018 to July 2019.

OBJECTIVE: Due to increased use of pre-exposure prohylaxis (PrEP) and its potential to affect HIV screening of blood donors, we undertook antiretroviral residual testing among HIV-negative male donors in England. METHODS: Residual plasma samples were obtainnd from 46 male donors confirmed positive for syphilis and 96 donors who were repeat reactive for HIV antibodies in screening but confirmed as HIV-negative by reference testing. These were tested for concentrations of tenofovir and emtricitabine by high-performance liquid chromatograhpy coupled with mass spectrometry. RESULTS: We found evidence of pre-exposure or post-exposure prophylaxis (PrEP/PEP) use in three male blood donors confirmed positive for syphilis (3 out of 46 screened, 6.5%). Two were estimated to have taken PrEP/PEP within a day of donating, and the third within 2 days. Two were new donors, whereas one had donated previously but acquired syphilis infection after his last donation. CONCLUSIONS: Our findings indicate that a small proportion of blood donors have not been disclosing PrEP/PEP use and therefore donating in non-compliance to donor eligibility criteria.

Total and Unbound Doravirine Concentrations and Viral Suppression in CSF.

We determined total and unbound concentrations of doravirine (DOR) in cerebrospinal fluid and blood plasma. Total and unbound DOR concentrations in cerebrospinal fluid exceeded the half-maximal effective concentration against wild-type virus (5.1 ng/mL) in all patients, suggesting that DOR may contribute to inhibit viral replication in this compartment.

An Open Label, Adaptive, Phase 1 Trial of High-Dose Oral Nitazoxanide in Healthy Volunteers: An Antiviral Candidate for SARS-CoV-2.

Repurposing approved drugs may rapidly establish effective interventions during a public health crisis. This has yielded immunomodulatory treatments for severe coronavirus disease 2019 (COVID-19), but repurposed antivirals have not been successful to date because of redundancy of the target in vivo or suboptimal exposures at studied doses. Nitazoxanide is a US Food and Drug Administration (FDA) approved antiparasitic medicine, that physiologically-based pharmacokinetic (PBPK) modeling has indicated may provide antiviral concentrations across the dosing interval, when repurposed at higher than approved doses. Within the AGILE trial platform (NCT04746183) an open label, adaptive, phase I trial in healthy adult participants was undertaken with high-dose nitazoxanide. Participants received 1,500 mg nitazoxanide orally twice-daily with food for 7 days. Primary outcomes were safety, tolerability, optimum dose, and schedule. Intensive pharmacokinetic (PK) sampling was undertaken day 1 and 5 with minimum concentration (Cmin ) sampling on days 3 and 7. Fourteen healthy participants were enrolled between February 18 and May 11, 2021. All 14 doses were completed by 10 of 14 participants. Nitazoxanide was safe and with no significant adverse events. Moderate gastrointestinal disturbance (loose stools or diarrhea) occurred in 8 participants (57.1%), with urine and sclera discoloration in 12 (85.7%) and 9 (64.3%) participants, respectively, without clinically significant bilirubin elevation. This was self-limiting and resolved upon drug discontinuation. PBPK predictions were confirmed on day 1 but with underprediction at day 5. Median Cmin was above the in vitro target concentration on the first dose and maintained throughout. Nitazoxanide administered at 1,500 mg b.i.d. with food was safe with acceptable tolerability a phase Ib/IIa study is now being initiated in patients with COVID-19.

The development and validation of a novel LC-MS/MS method for the simultaneous quantification of Molnupiravir and its metabolite ß-d-N4-hydroxycytidine in human plasma and saliva.

In light of the recent global pandemic, Molnupiravir (MPV) or EIDD-2801, developed for the treatment of patients with uncomplicated influenza, is now being trialled for the treatment of infections caused by highly pathogenic coronaviruses, including COVID-19. A sensitive LC-MS/MS method was developed and validated for the simultaneous quantification of MPV and its metabolite ß-d-N4-hydroxycytidine (NHC) in human plasma and saliva. The analytes were extracted from the matrices by protein precipitation using acetonitrile. This was followed by drying and subsequently injecting the reconstituted solutions onto the column. Chromatographic separation was achieved using a polar Atlantis C18 column with gradient elution of 1 mM Ammonium acetate in water (pH4.3) and 1 mM Ammonium acetate in acetonitrile. Analyte detection was conducted in negative ionisation mode using SRM. Analysis was performed using stable isotopically labelled (SIL) internal standards (IS). The m/z transitions were: MPV (328.1→126.0), NHC (258.0→125.9) and MPV-SIL (331.0→129.0), NHC-SIL (260.9→128.9). Validation was over a linear range of 2.5-5000 ng/ml for both plasma and saliva. Across four different concentrations, precision and accuracy (intra- and inter-day) were 15%; and recovery of both analytes from plasma and saliva was between 95% and 100% and 65-86% respectively. Clinical pharmacokinetic studies are underway utilising this method for determination of MPV and its metabolite in patients with COVID-19 infection.

Pharmacokinetic/pharmacodynamic investigation of raltegravir with or without lamivudine in the context of HIV-1 pre-exposure prophylaxis (PrEP).

BACKGROUND: To characterize their potential use in pre-exposure prophylaxis (PrEP) we compared the pharmacokinetics of raltegravir and lamivudine in genital tissue against ex vivo tissue infection with HIV-1. METHODS: Open-label trial of 36 HIV-negative females and males randomized to 7 days raltegravir 400 mg twice daily and 7 days raltegravir 400 mg+lamivudine 150 mg twice daily (after washout), or vice versa. Blood, saliva, rectal fluid, rectal tissue, vaginal fluid and vaginal tissue were sampled at baseline and on and off PrEP during a total of 12 days, for pharmacokinetics and antiviral activity via ex vivo HIV-1BaL challenge. Ex vivo infectivity was compared with baseline. The trial has been registered in https://clinicaltrials.gov/ with the identifier NCT03205566. RESULTS: Steady state for both drugs was reached by day 4. Dosing with raltegravir alone provided modest ex vivo HIV protection with higher drug levels in rectal tissue and vaginal tissue than in plasma on and off PrEP. Off PrEP, plasma and vaginal concentrations declined rapidly, while persisting in the rectum. On PrEP, the highest lamivudine concentrations were in the rectum, followed by vaginal tissue then plasma. Lamivudine washout was rapid in plasma, while persisting in the rectum and vagina. Raltegravir/lamivudine increased ex vivo protection on and off PrEP compared with raltegravir alone, reaching maximum protection at day 2 in rectal tissue and at day 8 in vaginal tissue. CONCLUSIONS: Raltegravir 400 mg+lamivudine 150 mg showed high levels of ex vivo HIV protection, associated with high drug concentrations persisting after discontinuation in vaginal and rectal compartments, supporting further investigation of these agents for PrEP.

Infant Exposure to Dolutegravir Through Placental and Breast Milk Transfer: A Population Pharmacokinetic Analysis of DolPHIN-1.

BACKGROUND: Rapid reduction in human immunodeficiency virus (HIV) load is paramount to prevent peripartum transmission in women diagnosed late in pregnancy. We investigated dolutegravir population pharmacokinetics in maternal plasma, umbilical cord, breast milk, and infant plasma samples from DolPHIN-1 participants (NCT02245022) presenting with untreated HIV late in pregnancy (28-36 weeks gestation). METHODS: Pregnant women from Uganda and South Africa were randomized (1:1) to daily dolutegravir (50 mg/d) or efavirenz-based therapy. Dolutegravir pharmacokinetic sampling (0-24 hours) was undertaken 14 days after treatment initiation and within 1-3 weeks after delivery, with matched maternal and cord samples at delivery. Mothers were switched to efavirenz, and maternal and infant plasma and breast milk samples were obtained 24, 48, or 72 hours after the switch. Nonlinear mixed-effects modeling was used to describe dolutegravir in all matrices and to evaluate covariates. RESULTS: A total of 28 women and 22 infants were included. Maternal dolutegravir was described by a 2-compartment model linked to a fetal and breast milk compartment. Cord and breast milk to maternal plasma ratios were 1.279 (1.209-1.281) and 0.033 (0.021-0.050), respectively. Infant dolutegravir was described by breast milk-to-infant and infant elimination rate constants. No covariate effects were observed. The median predicted infant dolutegravir half-life and median time to protein-adjusted 90% inhibitory concentration (0.064 mg/L) for those above this threshold were 37.9 (range, 22.1-63.5) hours and 108.9 (18.6-129.6) hours (4.5 [0.8-5.4] days) (n = 13), respectively. CONCLUSIONS: Breastfeeding contributed relatively little to infant plasma exposure, but a median of 4.5 days of additional prophylaxis to some of the breastfed infants was observed after cessation of maternal dolutegravir (3-15 days postpartum), which waned with time postpartum as transplacental dolutegravir cleared.