Substituted diaryl ether compounds as retinoic acid-related orphan Receptor-γt (RORγt) agonists.

The discovery of a series of substituted diarylether compounds as retinoic acid related orphan receptor γt (RORγt) agonists is described. Compound 1 was identified from deck mining as a RORγt agonist. Hit-to-lead optimization led to the identification of lead compound 5, which possesses improved potency (10x). Extensive SAR exploration led to the identification of a potent and selective compound 22, that demonstrated an improved pharmacokinetic profile and a dose-dependent pharmacodynamic response. However, when dosed in a MC38 syngeneic tumor model, no evidence of efficacy was observed. ©2020 Elsevier Science Ltd. All rights reserved.

High-throughput screening and rapid inhibitor triage using an infectious chimeric Hepatitis C virus.

The recent development of a Hepatitis C virus (HCV) infectious virus cell culture model system has facilitated the development of whole-virus screening assays which can be used to interrogate the entire virus life cycle. Here, we describe the development of an HCV growth assay capable of identifying inhibitors against all stages of the virus life cycle with assay throughput suitable for rapid screening of large-scale chemical libraries. Novel features include, 1) the use of an efficiently-spreading, full-length, intergenotypic chimeric reporter virus with genotype 1 structural proteins, 2) a homogenous assay format compatible with miniaturization and automated liquid-handling, and 3) flexible assay end-points using either chemiluminescence (high-throughput screening) or Cellomics ArrayScan™ technology (high-content screening). The assay was validated using known HCV antivirals and through a large-scale, high-throughput screening campaign that identified novel and selective entry, replication and late-stage inhibitors. Selection and characterization of resistant viruses provided information regarding inhibitor target and mechanism. Leveraging results from this robust whole-virus assay represents a critical first step towards identifying inhibitors of novel targets to broaden the spectrum of antivirals for the treatment of HCV.

HIV testing and HIV/AIDS treatment services in rural counties in 10 southern states: service provider perspectives.

CONTEXT: Forty percent of AIDS cases are reported in the southern United States, the region with the largest proportion of HIV/AIDS cases from rural areas. Data are limited regarding provider perspectives of the accessibility and availability of HIV testing and treatment services in southern rural counties. PURPOSE: We surveyed providers in the rural south to better understand: (1) the accessibility and availability, and (2) the facilitators and barriers of HIV testing and treatment services. METHODS: All county health departments (N = 326) serving populations of <50,000 persons, within 10 southern states, were mailed surveys. Responding health departments identified up to 3 HIV testing sites and up to 3 HIV treatment sites to which they refer clients. FINDINGS: Overall, 243 of 326 (75%) health departments, 133 of 250 (53%) HIV testing sites, and 73 of 152 (48%) HIV treatment sites responded to the surveys. The number of testing sites per county ranged from 0 to 20; the number of treatment sites ranged from 0 to 4. An average distance of 50 miles for clients to travel for HIV treatment was reported by health department respondents as a barrier. Facilitators of HIV testing were (1) integrating HIV testing into other health services; (2) using rapid HIV testing; and (3) establishing easily accessible HIV testing locations and free testing services. CONCLUSION: Providers perceive that distance from local health departments to HIV treatment sites presents a barrier to HIV care for their clients. Future studies should ascertain clients' perspectives to ensure appropriate service provisions.

Evaluation of cynomolgus monkey pregnane X receptor, primary hepatocyte, and in vivo pharmacokinetic changes in predicting human CYP3A4 induction.

Monkeys have been proposed as an animal model to predict the magnitude of human clinical drug-drug interactions caused by CYP3A4 enzyme induction. To evaluate whether the cynomolgus monkey can be an effective in vivo model, human CYP3A4 inducers were evaluated both in vitro and in vivo. First, a full-length pregnane X receptor (PXR) was cloned from the cynomolgus monkey, and the sequence was compared with those of rhesus monkey and human PXR. Cynomolgus and rhesus monkey PXR differed by only one amino acid (A68V), and both were highly homologous to human PXR (approximately 96%). When the transactivation profiles of 30 compounds, including known inducers of CYP3A4, were compared between cynomolgus and human PXR, a high degree of correlation with EC(50) values was observed. These results suggest that cynomolgus and human PXR respond in a similar fashion to these ligands. Second, two known human CYP3A4 inducers, rifampicin and hyperforin, were tested in monkey and human primary hepatocytes for induction of CYP3A enzymes. Both monkey and human hepatocytes responded similarly to the inducers and resulted in increased RNA and enzyme activity changes of CYP3A8 and CYP3A4, respectively. Lastly, in vivo induction of CYP3A8 by rifampicin and hyperforin was shown by significant reductions of midazolam exposure that were comparable with those in humans. These results show that the cynomolgus monkey can be a predictive in vivo animal model of PXR-mediated induction of human CYP3A4 and can provide a useful assessment of the resulting pharmacokinetic changes of affected drugs.

Multiplexing a high-throughput liability assay to leverage efficiencies.

In order to identify potential cytochrome P-450 3A4 (drug-metabolizing enzyme) inducers at an early stage of the drug discovery process, a cell-based transactivation high-throughput luciferase reporter assay for the human pregnane X receptor (PXR) in HepG2 cells has been implemented and multiplexed with a viability end point for data interpretation, as part of a Lead Profiling portfolio of assays. As a routine part of Lead Profiling operations, assays are periodically evaluated for utility as well as for potential improvements in technology or process. We used a recent evaluation of our PXR-transactivation assay as a model for the application of Lean Thinking-based process analysis to lab-bench assay optimization and automation. This resulted in the development of a 384-well multiplexed homogeneous assay simultaneously detecting PXR transactivation and HepG2 cell cytotoxicity. In order to multiplex fluorescent and luminescent read-outs, modifications to each assay were necessary, which included optimization of multiple assay parameters such as cell density, plate type, and reagent concentrations. Subsequently, a set of compounds including known cytotoxic compounds and PXR inducers were used to validate the multiplexed assay. Results from the multiplexed assay correlate well with those from the singleplexed assay formats measuring PXR transactivation and viability separately. Implementation of the multiplexed assay for routine compound profiling provides improved data quality, sample conservation, cost savings, and resource efficiencies.

The costs of HIV antiretroviral therapy adherence programs and impact on health care utilization.

From a trial comparing interventions to improve adherence to antiretroviral therapy-directly administered antiretroviral therapy (DAART) or an intensive adherence case management (IACM)-to standard of care (SOC), for HIV-infected participants at public HIV clinics in Los Angeles County, California, we examined the cost of adherence programs and associated health care utilization. We assessed differences between DAART, IACM, and SOC in the rate of hospitalizations, hospital days, and outpatient and emergency department visits during an average of 1.7 years from study enrollment, beginning November 2001. We assigned costs to health care utilization and program delivery. We calculated incremental costs of DAART or IACM v SOC, and compared those costs with savings in health care utilization among participants in the adherence programs. IACM participants experienced fewer hospital days compared with SOC (2.3 versus 6.7 days/1000 person-days, incidence rate ratio [IRR]: 0.34, 97.5% confidence interval [CI]: 0.13-0.87). DAART participants had more outpatient visits than SOC (44.2 versus 31.5/1000 person-days, IRR: 1.4; 97.5% CI: 1.01-1.95). Average per-participant health care utilization costs were $13,127, $8,988, and $14,416 for DAART, IACM, and SOC, respectively. Incremental 6-month program costs were $2,120 and $1,653 for DAART and IACM participants, respectively. Subtracting savings in health care utilization from program costs resulted in an average net program cost of $831 per DAART participant; and savings of $3,775 per IACM participant. IACM was associated with a significant decrease in hospital days compared to SOC and was cost saving when program costs were compared to savings in health care utilization.

Evaluation of 170 xenobiotics as transactivators of human pregnane X receptor (hPXR) and correlation to known CYP3A4 drug interactions.

The human transcription factor pregnane X receptor (hPXR) is a key regulator of enzyme expression, especially cytochrome P450 3A4 (CYP3A4). Due to the prominence of CYP3A4 in the elimination of many drugs, the development of high throughput in vitro models to predict the effect of drugs on CYP3A4 expression have increased. To better interpret and predict potential drug-drug interactions due to CYP3A4 enzyme induction, we evaluated 170 xenobiotics in a hPXR transactivation assay and compared these results to known clinical drug-drug interactions. Of the 170 xenobiotics tested, 54% of them demonstrated some level of hPXR transactivation. By taking into consideration cell culture conditions (solubility, cytotoxicity, appropriate drug concentration in media), as well as in vivo pharmacokinetics (therapeutic plasma C(max), distribution, route of administration, dosing regimen, liver exposure, potential to inhibit CYP3A4), the risk potential of CYP3A4 enzyme induction for most compounds reduced dramatically. By employing this overall interpretation strategy, the final percentage of compounds predicted to significantly induce CYP3A4 reduced to 5%, all of which are known to cause drug-drug interactions. Also, this is the first report that identifies several potent compounds that have the ability to transactivate hPXR that previously have not been identified, such as terbinafine, diclofenac, sildenafil, glimepiride, montelukast, and ticlopidine.

A randomized trial of directly administered antiretroviral therapy and adherence case management intervention.

BACKGROUND: A randomized, controlled trial was conducted to evaluate the impact of a directly administered antiretroviral therapy program (DAART) and intensive adherence case management (IACM) intervention on virologic and immunologic response to highly active antiretroviral therapy (HAART) among patients at 3 public human immunodeficiency virus clinics in Los Angeles County, California. METHODS: Participants included 250 treatment-naive and treatment-experienced persons for whom no more than 1 prior HAART regimen had failed. Five days per week for 6 months, a community worker delivered 1 HAART dose to DAART participants and observed the participant take it. IACM participants met weekly with a case manager to overcome barriers to HAART adherence. A control group (the standard of care [SOC] group) received the usual care. RESULTS: The majority of patients were Latino (64%) or African American (24%); 57% were monolingual Spanish speakers. Seventy-five percent of the patients were male, and 64% reported an annual income of <10,000 dollars. In an intent-to-treat analysis, no statistical differences were observed in the percentage of patients with an undetectable viral load (i.e., <400 copies/mL) at 6 months between the DAART group (54%), IACM group (60%), and SOC group (54%; P>.05). An on-treatment analysis determined that there were no statistical differences in the percentage of patients with an undetectable viral load at 6 months between the DAART group (71%), IACM group (80%), and SOC group (74%; P>.05). Additionally, there were no statistical differences in 6-month changes in the CD4+ cell count or in self-reported adherence to therapy. CONCLUSIONS: Among patients with limited prior HAART experience and adherence barriers that had not been assessed before randomization, no differences were found in virologic or immunologic response for DAART or IACM, compared with SOC, at 6 months. DAART and IACM did not improve short-term outcomes when SOC included other means of adherence support that were not controlled for by the study design.

Analysis of cellular events using CellCard System in cell-based high-content multiplexed assays.

High-content screening technologies utilize assays that monitor and quantify multiple cellular events. These assays are typically performed on a single cell type with automated microscopy and image analysis. However, in order to better understand the selectivity of a compound across multiple cell lines, these types of assay must be run serially, which is time consuming. The CellCard System developed by Vitra Bioscience enables multiple cell types to be assayed within a single microtiter well, thereby enabling the simultaneous determination of cellular responses across ten cell types. This multiplexed approach could address the demand for assay capacity, increase the quality of the biologic data, reduce timelines, and improve cost-effectiveness in hit identification and lead evaluation. The authors have carried out an in-depth evaluation of this technology platform using ten cancer cell lines and a library of compounds that affect cellular growth through different mechanisms. Multiple assays were used to investigate the compound effects on membrane integrity, cell cycle progression and apoptosis. In this technology review, the authors discuss personal experience with assay validation, data analysis, results such as cell type-specific compound effects, and the potential application of the CellCard System in drug discovery.

Characterization of a new class of selective nonsteroidal progesterone receptor agonists.

The identification of a new series of selective nonsteroidal progesterone receptor (PR) agonists is reported. Using a high-throughput screening assay based on the measurement of transactivation of a mouse mammary tumor virus promoter-driven luciferase reporter (MMTV-Luc) in human breast cancer T47D cells, a benzimidazole-2-thione analog was identified. Compound 1 showed an apparent EC50 of 53 nM and efficacy of 93% with respect to progesterone. It binds to PR with high affinity (Ki nM), but had no or very low affinity for other steroid hormone receptors. Structure-activity relationship studies of a series of benzimidazole-2-thione analogs revealed critical positions for high PR binding affinity and transactivation potency as well as receptor selectivity, as exemplified by 25. Compound 25 binds to human PR with high affinity (Ki nM) and had at least > 1000-fold selectivity for PR versus other steroid receptors. Molecular modeling studies suggested that these agonists overlap favorably with progesterone in the ligand-binding domain of PR. In T47D cells, compound 25 acted as a full agonist in the MMTV-Luc reporter assay, as well as in the induction of endogenous alkaline phosphatase activity with apparent EC50 values of 4 and 9 nM, respectively. In the immature rat model, compound 25 provided a significant suppression of estrogen-induced endometrium hypertrophy as measured by luminal epithelial height. In contrast, compound 25 was inactive in the luteinizing hormone release assay in young ovariectomized rats. These benzimidazole-2-thione analogs constitute a new series of nonsteroidal PR agonists with an excellent steroid receptor selectivity profile. The differential activities observed in the in vivo progestogenic assays in rat models suggest that these analogs can act as selective PR modulators.

Identification of a pharmaceutical compound that partially corrects the Niemann-Pick C phenotype in cultured cells.

Niemann-Pick C (NPC) is an autosomal recessive lysosomal lipid storage disease characterized by progressive central nervous system degeneration. In cultured human NPC fibroblasts, LDL-derived cholesterol accumulates in lysosomes and endosomes, LDL-cholesterol transport from endocytic compartments to other cellular compartments is delayed, and LDL does not elicit normal homeostatic responses. Currently, there is no therapy that delays the onset of neurological symptoms or prolongs the life span of NPC children. We have developed and implemented an amphotericin B-mediated cytotoxicity assay to screen for potential therapeutic drugs that induce cholesterol movement in cultured NPC cells. NPC cells are relatively resistant to amphotericin B killing due to intracellular sequestration of cellular cholesterol. The screen was carried out using simian virus 40-transformed ovarian granulosa cells from the npc (nih) mouse model of NPC disease. A library of 44240 compounds was screened and 55 compounds were identified that promote amphotericin B-mediated killing of NPC cells. One compound, NP-27, corrected the NPC phenotype by four different measures of cholesterol homeostasis. In addition to making NPC cells more sensitive to amphotericin B, NP-27 stimulated two separate cholesterol transport pathways and restored LDL stimulation of cholesterol esterification to near normal levels.

Cardiovascular risk factors in ethnic minority women aged < or =30 years.

Men and women of African and South Asian ancestry in the United States are increasingly recognized as being at greater risk for coronary heart disease (CHD) than Caucasians of European ancestry. Relatively little data on the genetic and lifestyle risk factors that predispose women to CHD in these ethnic minorities are available. We compared coronary risk factors in a volunteer sample of African-American, Asian Indian American, and Caucasian American women of college age. Life style, dietary, hemodynamic and anthropometric parameters, and laboratory data were sought from 70 subjects in each ethnic group. African-American women were found to have lower triglyceride levels and higher apolipoproten A-1, high-density lipoprotein (HDL), lipoprotein (a) (Lp(a)), fibrinogen, and fasting insulin levels. They also consumed more fat and cholesterol than their peers, had a higher percentage of body fat, body weight, and body mass indexes, and reported less physical activity than Caucasians. Asian Indian American women had higher Lp(a), HDL, and fibrinogen levels than Caucasian American women, and also reported less physical activity. Thus, young African- American and Asian Indian American women have several modifiable risk factors as well as some nontraditional lipid risk factors that warrant consideration for explaining the increased prevalence of CHD in these ethnic groups. The tendency toward peripheral insulin insensitivity and increased body fat in this age group of African-American women suggests diet and exercise may reduce the risk of subsequent CHD.