Population pharmacokinetics of tenofovir, emtricitabine and intracellular metabolites in transgender women.

AIMS: Transgender women (TGW) have been underrepresented in trials and use gender-affirming hormonal therapies (GAHT) that may alter renal function by significantly increasing creatinine clearance. Population pharmacokinetic (popPK) models and simulations would aid in understanding potential differences in emtricitabine/tenofovir disproxil fumarate (F/TDF) parent-metabolite concentrations in TGW on GAHT when compared to cisgender men (CGM) not exposed to GAHT. METHODS: Pharmacokinetic (PK) data from a Phase 1, open-label clinical trial with directly observed therapy of daily F/TDF consisting of 8 TGW and 8 CGM was utilized for model building. PopPK analysis was performed using nonlinear mixed effects modelling (NONMEM 7.5.0). Covariates of body weight, creatinine clearance, and gender were evaluated. Final models were subjected to Monte Carlo simulations to compare drug exposure following once daily and on-demand (IPERGAY 2 + 1 + 1) dosing of F/TDF. RESULTS: Tenofovir (TFV) and emtricitabine PK were best described by a 2-compartment model, first-order absorption/elimination with absorption lag time. Parent models were linked to their metabolites by first order formation and elimination. Creatinine clearance was a significant covariate influencing clearance in both models. Simulations demonstrated that at least 2, weekly 2 + 1 + 1 cycles of on-demand dosing in TGW on GAHT is necessary for TFV-diphosphate to reach similar exposure after the initial week of on-demand dosing in CGM not on GAHT. CONCLUSION: PopPK models of TFV, emtricitabine and intracellular metabolites in TGW were established. Dose simulations revealed that TGW should be treated for at least 2 weeks to have comparable exposures to CGM.

Lumen-apposing stents versus plastic stents in the management of pancreatic pseudocysts: a large, comparative, international, multicenter study.

BACKGROUND: Larger caliber lumen-apposing stents (LAMSs) have been increasingly used in the management of pancreatic fluid collections, specifically when solid debris is present; however, their advantages over smaller caliber plastic stents in the management of pancreatic pseudocysts are unclear. The aim of this study was to investigate the safety and efficacy of LAMS specifically in the management of pancreatic pseudocysts compared with double-pigtail plastic stents (DPPSs). METHODS: We performed a multicenter, international, retrospective study between January 2012 and August 2016. A total of 205 patients with a diagnosis of pancreatic pseudocysts were included, 80 patients received LAMSs and 125 received DPPSs. Measured outcomes included clinical success, technical success, adverse events, stent dysfunction, pancreatic pseudocyst recurrence, and need for surgery. RESULTS: Technical success was similar between the LAMS and the DPPS groups (97.5 % vs. 99.2 %; P = 0.32). Clinical success was higher for LAMSs than for DPPSs (96.3 % vs. 87.2 %; P = 0.03). While the need for surgery was similar between the two groups (1.3 % vs. 4.9 %, respectively; P = 0.17), the use of percutaneous drainage was significantly lower in the LAMS group (1.3 % vs. 8.8 %; P = 0.03). At 6-month follow-up, the recurrence rate was similar between the groups (6.7 % vs 18.8 %, respectively; P = 0.12). The rate of adverse events was significantly higher in the DPPS group (7.5 % vs. 17.6 %; P = 0.04). There was no difference in post-procedure mean length of hospital stay (6.3 days [standard deviation 27.9] vs. 3.7 days [5.7]; P = 0.31). CONCLUSION: When compared to DPPSs, LAMSs are a safe, feasible, and effective modality for the treatment of pancreatic pseudocysts and are associated with a higher rate of clinical success, shorter procedure time, less need for percutaneous interventions, and a lower overall rate of adverse events.

Endoscopic evaluation during the COVID-19 pandemic: Observational study of the experience in community practices.

Endoscopic screening is used widely to minimize the rates of colorectal cancer cases and deaths. During highly virulent infectious disease pandemics such as the coronavirus disease 2019 (COVID-19) pandemic, it is essential to weigh the risks and benefits of receiving endoscopy, especially in regions with moderately high viral infection rates. An observational study was conducted to assess the number of patients seen for endoscopic procedure at 2 of our surgery centers. Reasons for their procedure were collected in addition to information regarding any positive COVID-19 cases. This study considers the rate of severe acute respiratory syndrome coronavirus 2 infection along with the number of colorectal cancer cases encountered at a community endoscopy center to suggest that the benefits of undergoing endoscopic evaluation may outweigh the risks of attending an endoscopy procedure during the COVID-19 pandemic. One of the main reasons patients underwent endoscopic procedure was for colon cancer screenings (41.9%), and 5 of 1020 patients seen during the observation period were diagnosed with cancer. Of these 1020 patients, 8 were found to have positive tests for COVID-19 within 2 to 4 weeks after their procedure.

Examining the Safety, Pharmacokinetics, and Pharmacodynamics of a Rectally Administered IQP-0528 Gel for HIV Pre-Exposure Prophylaxis: A First-In-Human Study.

A lubricating microbicide gel designed for rectal and vaginal use would provide a behaviorally congruent strategy to enhance pre-exposure prophylaxis adherence and reduce HIV infection risk. In this study, we report the first-in-human evaluation of such a gel containing 1% IQP-0528, an investigational antiretroviral. Seven HIV-1-negative participants received one 10 mL rectal dose of radiolabeled 1% IQP-0528 gel. We assessed safety; IQP-0528 pharmacokinetics in plasma, and rectal and vaginal tissue; ex vivo local pharmacodynamics (PD); and colorectal distribution. The 1% gel was determined to be safe with one mild event attributed to study product and no effects on rectal tissue histology. All concentrations measured in plasma and vaginal tissue were below the limit of quantitation. Median IQP-0528 concentrations in rectal tissue exceeded the in vitro EC95 against HIV-1 (0.07 ng/mg) by 3-5 h of dosing and remained above this concentration for at least 24 h, despite a 3-log reduction in concentration over this duration of time. Rectal tissue PD-assessed by ex vivo HIV challenge-demonstrated significant p24 antigen reduction 3-5 h postdose compared with baseline (p = .05), but not 24-26 h postdose (p = .75). Single-photon emission computed tomography/computed tomography imaging revealed that product distribution was localized to the rectosigmoid. The IQP-0528 gel possesses desirable features for a topical microbicide including: local safety with no systemic absorption, delivery of locally high IQP-0528 concentrations, and significant reductions in ex vivo HIV infectivity. However, the gel is limited by its rapid clearance and inability to penetrate vaginal tissues following rectal dosing. Clinical Trial Registration number: NCT03082690.

Differential requirements for actin polymerization, calmodulin, and Ca2+ define distinct stages of lysosome/phagosome targeting.

Fusion of phagosomes with late endocytic organelles is essential for cellular digestion of microbial pathogens, senescent cells, apoptotic bodies, and retinal outer segment fragments. To further elucidate the biochemistry of the targeting process, we developed a scintillation proximity assay to study the stepwise association of lysosomes and phagosomes in vitro. Incubation of tritium-labeled lysosomes with phagosomes containing scintillant latex beads led to light emission in a reaction requiring cytosol, ATP, and low Ca(2+) concentrations. The nascent complex was sensitive to disruption by alkaline carbonate, indicating that the organelles had "docked" but not fused. Through inhibitor studies and fluorescence microscopy we show that docking is preceded by a tethering step that requires actin polymerization and calmodulin. In the docked state ongoing actin polymerization and calmodulin are no longer necessary. The tethering/docking activity was purified to near homogeneity from rat liver cytosol. Major proteins in the active fractions included actin, calmodulin and IQGAP2. IQGAPs are known to bind calmodulin and cross-link F-actin, suggesting a key coordinating role during lysosome/phagosome attachment. The current results support the conclusion that lysosome/phagosome interactions proceed through distinct stages and provide a useful new approach for further experimental dissection.

Transgender women on oral HIV pre-exposure prophylaxis have significantly lower tenofovir and emtricitabine concentrations when also taking oestrogen when compared to cisgender men.

INTRODUCTION: Oral HIV Pre-Exposure Prophylaxis (PrEP) with tenofovir (TFV) disoproxil fumarate (TDF)/emtricitabine (FTC) is highly effective. Transgender women (TGW) have increased HIV risk, but have been underrepresented in trials. For TGW on oestrogens for gender-affirming hormone treatment (GAHT), TDF/FTC-oestrogen interactions may negatively affect HIV prevention or gender-affirming goals. Our aim was to evaluate any pharmacokinetic drug-drug interaction between GAHT and TDF/FTC. METHODS: We performed a pharmacokinetic study, in an urban outpatient setting in 2016 to 2018, of the effects of GAHT on TFV, FTC and the active forms TFV diphosphate (TFV-DP) and FTC triphosphate (FTC-TP) in eight TGW and eight cisgender men (CGM). At screening, participants were HIV negative. TGW were to maintain their GAHT regimens and have plasma oestradiol concentrations >100 pg/mL. Under direct observation, participants took oral TDF/FTC daily for seven days. At the last dose, blood was collected pre-dose, one, two, four, six, eight and twenty-four hours, and colon biopsies were collected at 24 hours to measure drug concentration. TGW versus CGM concentration comparisons used non-parametric tests. Blood and colon tissue were also obtained to assess kinase expression. RESULTS: Plasma TFV and FTC C24 (trough) concentrations in TGW were lower by 32% (p = 0.010) and 32% (p = 0.038) respectively, when compared to CGM. Plasma TFV and FTC 24-hr area under the concentration-time curve in TGW trended toward and was significantly lower by 27% (p = 0.065) and 24% (p = 0.028) respectively. Peak plasma TFV and FTC concentrations, as well as all other pharmacokinetic measures, were not statistically significant when comparing TGW to CGM. Oestradiol concentrations were not different comparing before and after TDF/FTC dosing. Plasma oestrogen concentration, renal function (estimated creatinine clearance and glomerular filtration rate), and TFV and FTC plasma concentrations (trough and area under the concentration-time curve) were all correlated. CONCLUSIONS: GAHT modestly reduces both TFV and FTC plasma concentrations. In TGW taking GAHT, it is unknown if this reduction will impact the HIV protective efficacy of a daily PrEP regimen. However, the combination of an on demand (2 + 1 + 1) PrEP regimen and GAHT may result in concentrations too low for reliable prevention of HIV infection.

Sustained virologic response rates in patients with chronic hepatitis C genotype 6 treated with ledipasvir+sofosbuvir or sofosbuvir+velpatasvir.

BACKGROUND: Hepatitis C virus (HCV) genotype 6 (GT 6) is the predominant genotype among certain Asian populations. The availability of newer DAA options is limited in many parts of Asia. AIM: To compare sustained virologic response (SVR-12) rates between ledipasvir and sofosbuvir (LDV+SOF) and velpatasvir+SOF (SOF+VEL) for patients with HCVGT6 infection. METHOD: Retrospective study of consecutive adult HCVGT6 patients identified via ICD 9 code: 070.5 from United States treatment centers. Treatment was LDV+SOF or SOF+VEL for 8-24 weeks. A 1:1 propensity score matching (PSM) on HCV RNA, cirrhosis, alanine aminotransferase, aspartate aminotransferase, platelets, and fibrosis score was conducted among the treatment-naïve HCVGT6 patients to balance groups and isolate treatment effects. RESULTS: After exclusion criteria, 149 patients remained (n = 135 treatment-naïve; n = 14 treatment-experienced). The mean age was 63.8 ± 10.2 years, 66.9% male, and 93.9% Vietnamese. In treatment-naïve arm, 52.2% LDV+SOF cohort were cirrhotic compared to 11.6% SOF+VEL cohort (P < 0.0001). SVR-12 for LDV+SOF was 96.4% and 100% for the SOF+VEL cohort (P = 0.22). SVR-12 for cirrhotic patients was 95.4% (n = 41/43) for LDV+SOF and 100.0% (n = 5/5) for SOF+VEL (P = 0.62). After PSM (n = 33 per group), LDV+SOF SVR-12 rate was 97.0% compared to SOF+VEL SVR-12 of 100% (P = 0.31). The treatment-experienced group (n = 14), were all treated with LDV+SOF with an SVR-12 of 92.3%. CONCLUSION: Whether treatment-naïve, treatment-experienced, or cirrhotic patients with HCV GT 6 residing in the US had excellent outcomes when treated with SOF+VEL or LDV+SOF. Since LDV+SOF is more readily available globally, our results may provide clinicians with a treatment option when cost and availability limit the treatment choice.

Lubricant Provides Poor Rectal Mucosal HIV Coverage.

Given the rising HIV incidence in men who have sex with men (MSM) despite repeatedly proven effectiveness of oral HIV pre-exposure prophylaxis, behaviorally congruent periodic dosing strategies, such as dosing microbicides as lubricants, are now in demand. Rectal microbicide gel studies largely administer gels using vaginal applicators, which have not been well received and do not mimic lubricant use. We compared rectal gel manually dosed as lubricant with applicator dosing in five healthy, HIV-negative MSM who received 10 or 3.5 ml of 99mTc-DTPA-radiolabeled hydroxyethyl cellulose universal placebo gel intrarectally. After washout, participants received 10 ml of radiolabeled Wet® Original® lubricant to apply to the anus with fingers and/or a phallus in a manner typical of sexual lubricant use with a partner, followed by simulated receptive anal intercourse. Single-photon emission computed tomography with transmission computed tomography was performed 4 h after each gel administration. Manual dosing was associated with more variable rectosigmoid distribution, 4.4-15.3 cm from the anorectal junction, compared with more uniform distribution, 5.9-7.4 and 5.3-7.6 cm after 10 and 3.5 ml applicator dosing, respectively. A significantly smaller fraction of the initial 10 ml dose was retained within the colon after manual dosing, 3.4%, compared with 94.9% and 88.4% after 10 and 3.5 ml applicator dosing, respectively (both p < .001). Manual dosing of a sexual lubricant delivered a small, variable fraction of the dose with variable rectosigmoid distribution compared with applicator dosing. These results raise concern that dosing a rectal microbicide gel as a sexual lubricant may not provide adequate or predictable mucosal coverage for HIV protection.

Dose Frequency Ranging Pharmacokinetic Study of Tenofovir-Emtricitabine After Directly Observed Dosing in Healthy Volunteers to Establish Adherence Benchmarks (HPTN 066).

Oral preexposure prophylaxis (PrEP) trials report disparate efficacy attributed to variable adherence. HPTN 066 was conducted to establish objective, quantitative benchmarks for discrete, regular levels of adherence using directly observed dosing of tenofovir (TFV) disoproxil fumarate (TDF)/emtricitabine (FTC). Healthy, HIV-uninfected men and women were randomized to one of four oral regimens of fixed-dose TDF 300 mg/FTC 200 mg tablet for 5 weeks with all doses observed: one tablet weekly (one/week), one tablet twice weekly (two/week), two tablets twice weekly (four/week), or one tablet daily (seven/week). Trough serum TFV and FTC, peripheral blood mononuclear cell (PBMC), and CD4(+) TFV-diphosphate (TFV-DP) and FTC-triphosphate (FTC-TP) concentrations were determined throughout dosing and 2 weeks after the last dose. Rectosigmoidal, semen, and cervicovaginal samples were collected for drug assessment at end of dosing and 2 weeks later in a subset of participants. The 49 enrolled participants tolerated the regimens well. All regimens achieved steady-state concentrations by the second dose for serum TFV/FTC and by 7 days for PBMC TFV-DP/FTC-TP. Steady-state median TFV-DP predose concentrations demonstrated dose proportionality: one/week 1.6 fmol/10(6) PBMCs, two/week 9.1, four/week 18.8, seven/week, 36.3. Further, TFV-DP was consistently quantifiable 2 weeks after the last dose for the ≥4/week regimens. Adherence benchmarks were identified using receiver operating characteristic curves, which had areas under the curve ≥0.93 for all analytes in serum and PBMCs. Intersubject and intrasubject coefficients of variation (%CV) ranged from 33% to 63% and 14% to 34%, respectively, for all analytes in serum and PBMCs. Steady-state PBMC TFV-DP was established earlier and at lower concentrations than predicted and was the only analyte demonstrating predose concentration dose proportionality. Steady-state daily dosing serum TFV and PBMC TFV-DP was consistent with highly effective PrEP clinical trials. HPTN 066 provides adherence benchmarks for oral TFV/FTC regimens to assist interpreting study outcomes.

Candida esophagitis in a human immunodeficiency virus-1-positive elite controller with hepatitis C virus cirrhosis.

We describe a case of Candida esophagitis in a human immunodeficiency virus elite controller with a preserved CD4 count, a population in which opportunistic infections are almost never seen. The patient has hepatitis C virus coinfection and compensated cirrhosis, suggesting a possible multifactorial etiology of immune dysregulation.

Immunoglobulin G signaling activates lysosome/phagosome docking.

An important role of IgG antibodies in the defense against microbial infections is to promote the ingestion and killing of microbes by phagocytes. Here, we developed in vivo and in vitro approaches to ask whether opsonization of particles with IgG enhances intracellular targeting of lysosomes to phagosomes. To eliminate the effect of IgG on the ingestion process, cells were exposed to latex beads at 15-20 degrees C, which allows engulfment of both IgG-coated and uncoated beads but prevents the fusion of lysosomes with phagosomes. Upon shifting the temperature to 37 degrees C, phagosomes containing IgG beads matured significantly faster into phagolysosomes as judged by colocalization with lysosomal markers. The IgG effect was independent of other particle-associated antigens or serum factors. Lysosome/phagosome attachment was also quantified biochemically with a cytosol-dependent scintillation proximity assay. Interactions were enhanced significantly in reactions containing cytosol from mouse macrophages that had been exposed to IgG-coated beads, indicating that IgG signaling modulates the cytosolic-targeting machinery. Similar results were obtained with cytosol from primary human monocytes, human U-937 histiocytic lymphoma cells and from Chinese hamster ovary (CHO) cells transfected with a human IgG (Fcgamma) receptor. IgG-induced activation is shown to affect the actin-dependent tethering/docking stage of the targeting process and to proceed through a pathway involving protein kinase C. These results provide a rare example of an extracellular signal controlling membrane targeting on the level of tethering and docking. We propose that this pathway contributes to the role of antibodies in the protection against microbial infections.

Transcriptional regulation of phagocytosis-induced membrane biogenesis by sterol regulatory element binding proteins.

In the process of membrane biogenesis several dozen proteins must operate in precise concert to generate approximately 100 lipids at appropriate concentrations. To study the regulation of bilayer assembly in a cell cycle-independent manner, we have exploited the fact that phagocytes replenish membranes expended during particle engulfment in a rapid phase of lipid synthesis. In response to phagocytosis of latex beads, human embryonic kidney 293 cells synthesized cholesterol and phospholipids at amounts equivalent to the surface area of the internalized particles. Lipid synthesis was accompanied by increased transcription of several lipogenic proteins, including the low-density lipoprotein receptor, enzymes required for cholesterol synthesis (3-hydroxy-3-methylglutaryl CoA synthase, 3-hydroxy-3-methylglutaryl CoA reductase), and fatty acid synthase. Phagocytosis triggered the proteolytic activation of two lipogenic transcription factors, sterol regulatory element binding protein-1a (SREBP-1a) and SREBP-2. Proteolysis of SREBPs coincided with the appearance of their transcriptionally active N termini in the nucleus and 3-fold activation of an SREBP-specific reporter gene. In previous studies with cultured cells, proteolytic activation of SREBP-1a and SREBP-2 has been observed in response to selective starvation of cells for cholesterol and unsaturated fatty acids. However, under the current conditions, SREBP-1a and SREBP-2 are induced without lipid deprivation. SREBP activation is inhibited by high levels of the SREBP-interacting proteins Insig1 or the cytosolic domain of SREBP cleavage-activating protein. Upon overexpression of these proteins, phagocytosis-induced transcription and lipid synthesis were blocked. These results identify SREBPs as essential regulators of membrane biogenesis and provide a useful system for further studies on membrane homeostasis.