Human Pharmacokinetic and CYP3A DDI Prediction of GDC-2394 using PBPK Modeling and Biomarker Assessment.

Physiologically-based pharmacokinetic (PBPK) modeling was used to predict the human pharmacokinetics and drug-drug interaction (DDI) of GDC-2394. PBPK models were developed using in vitro and in vivo data to reflect the oral and IV PK profiles of mouse, rat, dog and monkey. The learnings from preclinical PBPK models were applied to a human PBPK model for prospective human PK predictions. The prospective human PK predictions were within 3-fold of the clinical data from the first in human (FIH) study, which was used to optimize and validate the PBPK model and subsequently used for DDI prediction. Based on the majority of PBPK modeling scenarios using the in vitro CYP3A induction data (mRNA and activity), GDC-2394 was predicted to have no-to-weak induction potential at 900 mg BID. Calibration of the induction mRNA and activity data allowed for the convergence of DDI predictions to a narrower range. The plasma concentrations of the 4ß-hydroxycholesterol (4ß-HC) were measured in the multiple ascending dose (MAD) study to assess the hepatic CYP3A induction risk. There was no change in plasma 4ß-HC concentrations after 7 days of GDC-2394 at 900 mg BID. A dedicated DDI study found that GDC-2394 has no induction effect on midazolam in humans, which was reflected by the totality of predicted DDI scenarios. This work demonstrates the prospective utilization of PBPK for human PK and DDI prediction in early drug development of GDC-2394. PBPK modeling accompanied with CYP3A biomarkers can serve as a strategy to support clinical pharmacology development plans. Significance Statement This work presents the application of PBPK modeling for prospective human PK and DDI prediction in early drug development. The strategy taken in this report represents a framework to incorporate various approaches including calibration of in vitro induction data and consideration of CYP3A biomarkers to inform on the overall CYP3A related DDI risk of GDC-2394.

Preclinical characterization of the absorption and disposition of the brain penetrant PI3K/mTOR inhibitor paxalisib and prediction of its pharmacokinetics and efficacy in human.

Glioblastoma multiforme (GBM) is the most common primary brain tumour in adults. Available treatments have not markedly improved patient survival in the last twenty years. However, genomic investigations have showed that the PI3K pathway is frequently altered in this glioma, making it a potential therapeutic target.Paxalisib is a brain penetrant PI3K/mTOR inhibitor (mouse Kp,uu 0.31) specifically developed for the treatment of GBM. We characterised the preclinical pharmacokinetics and efficacy of paxalisib and predicted its pharmacokinetics and efficacious dose in humans.Plasma protein binding of paxalisib was low, with the fraction unbound ranging from 0.25 to 0.43 across species. The hepatic clearance of paxalisib was predicted to be low in mice, rats, dogs and humans, and high in monkeys, from hepatocytes incubations. The plasma clearance was low in mice, moderate in rats and high in dogs and monkeys. Oral bioavailability ranged from 6% in monkeys to 76% in rats.The parameters estimated from the pharmacokinetic/pharmacodynamic modelling of the efficacy in the subcutaneous U87 xenograft model combined with the human pharmacokinetics profile predicted by PBPK modelling suggested that a dose of 56 mg may be efficacious in humans. Paxalisib is currently tested in Phase III clinical trials.

Residue-Level Characterization of Antibody Binding Epitopes Using Carbene Chemical Footprinting.

Characterization of antibody binding epitopes is an important factor in therapeutic drug discovery, as the binding site determines and drives antibody pharmacology and pharmacokinetics. Here, we present a novel application of carbene chemical footprinting with mass spectrometry for identification of antibody binding epitopes at the single-residue level. Two different photoactivated diazirine reagents provide complementary labeling information allowing structural refinement of the antibody binding interface. We applied this technique to map the epitopes of multiple MICA and CTLA-4 antibodies and validated the findings with X-ray crystallography and yeast surface display epitope mapping. The characterized epitopes were used to understand biolayer interferometry-derived competitive binding results at the structural level. We show that carbene footprinting provides fast and high-resolution epitope information critical in the antibody selection process and enables mechanistic understanding of function to accelerate the drug discovery process.

A Patient Decision Aid About Conservative Kidney Management in Advanced Kidney Disease: A Randomized Pilot Trial.

RATIONALE & OBJECTIVE: Available decision aids for patients about treatment of advanced chronic kidney disease (CKD) often lack information on conservative kidney management (CKM). We assessed the feasibility and acceptability of a decision aid on CKM among patients with advanced CKD and their family members. STUDY DESIGN: Randomized pilot trial. SETTING & PARTICIPANTS: Patients aged≥75 years with stage 4 or 5 CKD and their family members at 4 medical centers in the greater Seattle area between August 2020 and December 2021. INTERVENTIONS: Usual care with or without a decision aid on CKM. OUTCOME: Acceptability was assessed by attrition rates between the initial study visit (T1) and the 3-month follow-up evaluation (T3). The primary outcome and measure of feasibility was the proportion of participants who discussed CKM with a health care provider between T1 and T3. RESULTS: We randomized 92 patients of whom 86 (55.8% male; age 82±6 years; 82.6% White) completed T1-42 in the usual care arm and 44 in the usual care plus decision aid arm-and 56 family members of whom 53 (18.9% male; age 71±11 years; 86.8% White) completed T1-20 in usual care arm and 33 in the usual care plus decisions aid arm. The attrition rates were 21% versus 21% (P=1.0) for patients, and 10% versus 18% (P=0.46) for family members in the usual care versus usual care plus decisions aid arms. Receipt of the decision aid significantly increased discussion of CKM with a health care provider for patients (26.4% vs 3.0%, P=0.007) and family members (26.9% vs 0, P=0.02). LIMITATIONS: Possible limited generalizability because participants were a relatively homogenous group. The decision aid focuses on CKM and may be less applicable to those with limited knowledge of kidney replacement therapies. CONCLUSIONS: A CKM decision aid was feasible and acceptable, and increased discussion of this treatment option with health care providers. This aid may serve as a useful adjunct to the currently available educational tools on treatments for advanced CKD. FUNDING: Grant from a not-for-profit entity (National Palliative Care Research Center). TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT04919941.

Filling a nick in NIK: Extending the half-life of a NIK inhibitor through structure-based drug design.

Inhibition of NF-κB inducing kinase (NIK) has been pursued as a promising therapeutic target for autoimmune disorders due to its highly regulated role in key steps of the NF-κB signaling pathway. Previously reported NIK inhibitors from our group were shown to be potent, selective, and efficacious, but had higher human dose projections than desirable for immunology indications. Herein we report the clearance-driven optimization of a NIK inhibitor guided by metabolite identification studies and structure-based drug design. This led to the identification of an azabicyclo[3.1.0]hexanone motif that attenuated in vitro and in vivo clearance while maintaining NIK potency and increasing selectivity over other kinases, resulting in a greater than ten-fold reduction in predicted human dose.

Fostamatinib for the Treatment of Hospitalized Adults With Coronavirus Disease 2019: A Randomized Trial.

BACKGROUND: Coronavirus disease 2019 (COVID-19) requiring hospitalization is characterized by robust antibody production, dysregulated immune response, and immunothrombosis. Fostamatinib is a novel spleen tyrosine kinase inhibitor that we hypothesize will ameliorate Fc activation and attenuate harmful effects of the anti-COVID-19 immune response. METHODS: We conducted a double-blind, randomized, placebo-controlled trial in hospitalized adults requiring oxygen with COVID-19 where patients receiving standard of care were randomized to receive fostamatinib or placebo. The primary outcome was serious adverse events by day 29. RESULTS: A total of 59 patients underwent randomization (30 to fostamatinib and 29 to placebo). Serious adverse events occurred in 10.5% of patients in the fostamatinib group compared with 22% in placebo (P = .2). Three deaths occurred by day 29, all receiving placebo. The mean change in ordinal score at day 15 was greater in the fostamatinib group (-3.6 ±â€…0.3 vs -2.6 ±â€…0.4, P = .035) and the median length in the intensive care unit was 3 days in the fostamatinib group vs 7 days in placebo (P = .07). Differences in clinical improvement were most evident in patients with severe or critical disease (median days on oxygen, 10 vs 28, P = .027). There were trends toward more rapid reductions in C-reactive protein, D-dimer, fibrinogen, and ferritin levels in the fostamatinib group. CONCLUSION: For COVID-19 requiring hospitalization, the addition of fostamatinib to standard of care was safe and patients were observed to have improved clinical outcomes compared with placebo. These results warrant further validation in larger confirmatory trials. CLINICAL TRIALS REGISTRATION: Clinicaltrials.gov, NCT04579393.

An Integrated Strategy for Assessing the Metabolic Stability and Biotransformation of Macrocyclic Peptides in Drug Discovery toward Oral Delivery.

Macrocyclic peptides (MCPs) are an emerging class of promising drug modalities that can be used to interrogate hard-to-drug ("undruggable") targets. However, their poor intestinal stability is one of the major liabilities or obstacles for oral drug delivery. We therefore investigated the metabolic stability and biotransformation of MCPs via a systematic approach and established an integrated in vitro assay strategy to facilitate MCP drug discovery, with a focus on oral delivery liabilities. A group of diverse MCPs were incubated with representative matrices, including simulated intestinal fluid with pancreatin (SIFP), human enterocytes, liver S9 fractions, liver lysosomes, plasma, and recombinant enzymes. The results revealed that the stability and biotransformation of MCPs varied, with the major metabolic pathways identified in different matrices. Under the given conditions, the selected MCPs generally showed better stability in plasma compared to that in SIFP. Our data suggest that pancreatic enzymes act as the primary metabolic barrier for the oral delivery of MCPs, mainly through hydrolysis of their backbone amide bonds. Whereas in enterocytes, multiple metabolic pathways appeared to be involved and resulted in metabolic reactions such as oxidation and reduction in addition to hydrolysis. Further studies suggested that lysosomal peptidase cathepsin B could be a major enzyme responsible for the cleavage of side-chain amide bonds in lysosomes. Collectively, we developed and implemented an integrated assay for assessing the metabolic stability and biotransformation of MCPs for compound screening in the discovery stage toward oral delivery. The proposed question-driven assay cascade can provide biotransformation insights that help to guide and facilitate lead candidate selection and optimization.

Challenges to Shared Decision Making About Treatment of Advanced CKD: A Qualitative Study of Patients and Clinicians.

RATIONALE & OBJECTIVE: Greater understanding of the challenges to shared decision making about treatment of advanced chronic kidney disease (CKD) is needed to support implementation of shared decision making in clinical practice. STUDY DESIGN: Qualitative study. SETTING & PARTICIPANTS: Patients aged≥65 years with advanced CKD and their clinicians recruited from 3 medical centers participated in semi-structured interviews. In-depth review of patients' electronic medical records was also performed. ANALYTICAL APPROACH: Interview transcripts and medical record notes were analyzed using inductive thematic analysis. RESULTS: Twenty-nine patients (age 73±6 years, 66% male, 59% White) and 10 of their clinicians (age 52±12 years, 30% male, 70% White) participated in interviews. Four themes emerged from qualitative analysis: (1) competing priorities-patients and their clinicians tended to differ on when to prioritize CKD and dialysis planning above other personal or medical problems; (2) focusing on present or future-patients were more focused on living well now while clinicians were more focused on preparing for dialysis and future adverse events; (3) standardized versus individualized approach to CKD-although clinicians tried to personalize care recommendations to their patients, the patients perceived their clinicians as taking a monolithic approach to CKD that was predicated on clinical practice guidelines and medical literature rather than the patients' lived experiences with CKD and personal values and goals; and (4) power dynamics-patients described cautiously navigating a power differential in their therapeutic relationship with their clinicians whereas clinicians seemed less attuned to these power dynamics. LIMITATIONS: Thematic saturation was based on patient interviews. Themes presented might incompletely reflect clinicians' perspectives. CONCLUSIONS: Efforts to improve shared decision making for treatment of advanced CKD will likely need to explicitly address differences between patients and their clinicians in approaches to decision making about treatment of advanced CKD and perceived power imbalances in the therapeutic relationship.

Isotretinoin and its Metabolites Alter mRNA of Multiple Enzyme and Transporter Genes In Vitro, but Downregulation of Organic Anion Transporting Polypeptide Does Not Translate to the Clinic.

Isotretinoin [13-cis-retinoic acid (13cisRA)] is widely used for the treatment of neuroblastoma and acne. It acts via regulating gene transcription through binding to retinoic acid receptors. Yet, the potential for isotretinoin to cause transcriptionally mediated drug-drug interactions (DDIs) has not been fully explored. We hypothesized that isotretinoin and its active metabolites all-trans-retinoic acid (atRA) and 4-oxo-13cisRA would alter the transcription of enzymes and transporters in the human liver via binding to nuclear receptors. The goal of this study was to define the DDI potential of isotretinoin and its metabolites resulting from transcriptional regulation of cytochrome P450 and transporter mRNAs. In human hepatocytes (n = 3), 13cisRA, atRA, and 4-oxo-13cisRA decreased OATP1B1, CYP1A2, CYP2C9, and CYP2D6 mRNA and increased CYP2B6 and CYP3A4 mRNA in a concentration-dependent manner. The EC50 values for OATP1B1 mRNA downregulation ranged from 2 to 110 nM, with maximum effect (Emax ) ranging from 0.17- to 0.54-fold. Based on the EC50 and Emax values and the known circulating concentrations of 13cisRA and its metabolites after isotretinoin dosing, a 55% decrease in OATP1B1 activity was predicted in vivo. In vivo DDI potential was evaluated clinically in participants dosed with isotretinoin for up to 32 weeks using coproporphyrin-I (CP-I) as an OATP1B1 biomarker. CP-I steady-state serum concentrations were unaltered following 2, 8, or 16 weeks of isotretinoin treatment. These data show that isotretinoin and its metabolites alter transcription of multiple enzymes and transporters in vitro, but translation of these changes to in vivo drug-drug interactions requires clinical evaluation for each enzyme. SIGNIFICANCE STATEMENT: Isotretinoin and its metabolites alter the mRNA expression of multiple cytochrome P450s (CYPs) and transporters in human hepatocytes, suggesting that isotretinoin may cause clinically significant drug-drug interactions (DDIs). Despite the observed changes in organic anion transporting polypeptide 1B1 (OATP1B1) mRNA in human hepatocytes, no clinical DDI was observed when measuring a biomarker, coproporphyrin-I. Further work is needed to determine whether these findings can be extrapolated to a lack of a DDI with CYP1A2, CYP2B6, and CYP2C9 substrates.

Older Patients with Advanced Chronic Kidney Disease and Their Perspectives on Prognostic Information: a Qualitative Study.

BACKGROUND: Prognostic information is key to shared decision-making, particularly in life-limiting illness like advanced chronic kidney disease (CKD). OBJECTIVE: To understand the prognostic information preferences expressed by older patients with CKD. DESIGN AND PARTICIPANTS: Qualitative study of 28 consecutively enrolled patients over 65 years of age with non-dialysis dependent CKD stages 3b-5, receiving care in a multi-disciplinary CKD clinic. APPROACH: Semi-structured telephone or in-person interviews to explore patients' preference for and perceived value of individualized prognostic information. Interviews were analyzed using inductive content analysis. KEY RESULTS: We completed interviews with 28 patients (77.7 ± SD 6.8 years, 69% men). Patients varied in their preference for prognostic information and more were interested in their risk of progression to end-stage kidney disease (ESKD) than in life expectancy. Many conflated ESKD risk with risk of death, perceiving a binary choice between dialysis and quick decline and death. Patients expressed that prognostic information would allow them to plan, take care of important business, and think about their treatment options. Patients were accepting of prognostic uncertainty and imagined leveraging it to nurture hope or motivate them to better manage risk factors. They endorsed the desire to receive prognosis of life expectancy even though it may be hard to accept or difficult to talk about but worried it could create helplessness for other patients in their situation. CONCLUSION: Most, but not all, patients were interested in prognostic information and could see its value in motivating behavior change and allowing planning. Some patients expressed concern that information on life expectancy might cause depression and hopelessness. Therefore, prognostic information is most appropriate as part of a clinical conversation that fosters shared decision-making and helps patients consider treatment risks, benefits, and burdens in context of their lives.

Neutralizing Antibody Responses in COVID-19 Convalescent Sera.

Passive transfer of antibodies from COVID-19 convalescent patients is being used as an experimental treatment for eligible patients with SARS-CoV-2 infections. The United States Food and Drug Administration's (FDA) guidelines for convalescent plasma initially recommended target antibody titers of 160. We evaluated SARS-CoV-2 neutralizing antibodies in sera from recovered COVID-19 patients using plaque reduction neutralization tests (PRNT) at moderate (PRNT50) and high (PRNT90) stringency thresholds. We found that neutralizing activity significantly increased with time post symptom onset (PSO), reaching a peak at 31-35 days PSO. At this point, the number of sera having neutralizing titers of at least 160 was approximately 93% (PRNT50) and approximately 54% (PRNT90). Sera with high SARS-CoV-2 antibody levels (>960 enzyme-linked immunosorbent assay titers) showed maximal activity, but not all high-titer sera contained neutralizing antibody at FDA recommended levels, particularly at high stringency. These results underscore the value of serum characterization for neutralization activity.

Evaluation of Ipatasertib Interactions with Itraconazole and Coproporphyrin I and III in a Single Drug Interaction Study in Healthy Subjects.

Ipatasertib is a pan-AKT inhibitor in development for the treatment of cancer. Ipatasertib was metabolized by CYP3A4 to its major metabolite, M1 (G-037720), and was a P-gp substrate and OATP1B1/1B3 inhibitor in vitro. A phase I drug-drug interaction (DDI) study (n = 15) was conducted in healthy subjects to evaluate the effect of itraconazole (200-mg solution QD, 4 days), a strong CYP3A4 and P-gp inhibitor, on pharmacokinetics of ipatasertib (100-mg single dose). Itraconazole increased the Cmax and AUC0 -∞ of ipatasertib by 2.3- and 5.5-fold, respectively, increased the half-life by 53%, and delayed the tmax by 1 hour. The Cmax and AUC0-72h of its metabolite M1 (G-037720) reduced by 91% and 68%, respectively. This study confirmed that CYP3A4 plays a major role in ipatasertib clearance. Furthermore, the interaction of ipatasertib with coproporphyrin (CP) I and CPIII, the two endogenous substrates of OATP1B1/1B3, was evaluated in this study. CPI and CPIII plasma levels were unchanged in the presence of ipatasertib, both at exposures of 100 mg and at higher exposures in combination with itraconazole. This indicated no in vivo inhibition of OATP1B1/1B3 by ipatasertib. Additionally, it was shown that CPI and CPIII were not P-gp substrates in vitro, and itraconazole had no effect on CPI and CPIII concentrations in vivo. The latter is an important finding because it will simplify interpretation of future DDI studies using CPI/CPIII as OATP1B1/1B3 biomarkers. SIGNIFICANCE STATEMENT: This drug-drug interaction study in healthy volunteers demonstrated that CYP3A4 plays a major role in ipatasertib clearance, and that ipatasertib is not an organic anion transporting polypeptide 1B1/1B3 inhibitor. Furthermore, it was demonstrated that itraconazole, an inhibitor of CYP3A4 and several transporters, did not affect CPI/CPIII levels in vivo. This increases the understanding and application of these endogenous substrates as well as itraconazole in complex drug interaction studies.

Perspectives on Conservative Care in Advanced Kidney Disease: A Qualitative Study of US Patients and Family Members.

RATIONALE & OBJECTIVE: Little is known about perceptions of conservative care among patients with advanced kidney disease in the United States. STUDY DESIGN: Qualitative study using cognitive interviewing about attitudes regarding conservative care using decision aids on treatments for advanced kidney disease developed outside the United States. SETTING & PARTICIPANTS: 14 patients 75 years or older with advanced kidney disease, defined as estimated glomerular filtration rate≤20mL/min/1.73m2 and not receiving maintenance dialysis, and 6 of their family members. ANALYTICAL APPROACH: Thematic analysis of participants' reactions to descriptions of conservative care taken from various clinical care decision aids. RESULTS: Participants were mostly White (n=15) and had at least some college education (n=16). Four themes emerged from analysis of interviews: (1) core elements of conservative care: aspects of conservative care that were appealing to participants included a whole-person, team-based, and structured approach to care that focused on symptom management, maintaining current lifestyle, and managing health setbacks; (2) importance of how conservative care is framed: participants were more receptive to conservative care when this was framed as an active rather than passive treatment approach and were receptive to statements of uncertainty about future course of illness and prognosis; (3) an explicit approach to shared decision making: participants believed decisions about conservative care and dialysis should address considerations about risk and benefits of treatment options, family and clinician perspectives, and patients' goals, values, and preferences; and (4) relationship between conservative care and dialysis: although conservative care models outside the United States are generally intended to serve as an alternative to dialysis, participants' comments implied that they did not see conservative care and dialysis as mutually exclusive. LIMITATIONS: Themes identified may not generalize to the broader population of US patients with advanced kidney disease and their family members. CONCLUSIONS: Participants were favorably disposed to a whole-person multidisciplinary approach to conservative care, especially when framed as an active treatment approach. Models of conservative care excluding the possibility of dialysis were less embraced, suggesting that current models will require adaptation to meet the needs of US patients and their families.

Investigating the Utility of Humanized Pregnane X Receptor-Constitutive Androstane Receptor-CYP3A4/7 Mouse Model to Assess CYP3A-Mediated Induction.

Clinical induction liability is assessed with human hepatocytes. However, underpredictions in the magnitude of clinical induction have been reported. Unfortunately, in vivo studies in animals do not provide additional insight because of species differences in drug metabolizing enzymes and their regulatory pathways. To circumvent this limitation, transgenic animals expressing human orthologs were developed. The aim of this work was to investigate the utility of mouse models expressing human orthologs of pregnane X receptor, constitutive androstane receptor, and CYP3A4/7 (Tg-Composite) in evaluating clinical induction. Rifampin, efavirenz, and pioglitazone, which were employed to represent strong, moderate, and weak inducers, were administered at multiple doses to Tg-Composite animals. In vivo CYP3A activity was monitored by measuring changes in the exposure of the CYP3A probe substrate triazolam. After the in vivo studies, microsomes were prepared from their livers to measure changes of in vitro CYP3A4 activity. In both in vivo and in vitro, distinction of clinic induction was recapitulated as rifampin yielded the greatest inductive effect followed by efavirenz and pioglitazone. Interestingly, with rifampin, in vivo CYP3A activity was approximately 4-fold higher than in vitro activity. Conversely, there was no difference between in vivo and in vitro CYP3A activity with efavirenz. These findings are consistent with the report that, although rifampin exhibits differential inductive effects between the intestines and liver, efavirenz does not. These data highlight the promise of transgenic models, such as Tg-Composite, to complement human hepatocytes to enhance the translatability of clinical induction as well as become a powerful tool to further study mechanisms of drug disposition. SIGNIFICANCE STATEMENT: Underprediction of the magnitude of clinical induction when using human hepatocytes has been reported, and transgenic models may improve clinical translatability. The work presented here showcases the human orthologs of pregnane X receptor, constitutive androstane receptor, and CYP3A4/7 model, which was able to recapitulate the magnitude of clinical induction and to differentiate tissue-dependent induction observed with rifampin but not with efavirenz. These results not only foreshadow the potential application of such transgenic models in assessing clinical induction but also in further investigation of the mechanism of drug disposition.

A fatal case report of antibody-dependent enhancement of dengue virus type 1 following remote Zika virus infection.

BACKGROUND: Dengue virus (DENV) is endemic in many parts of the world. Antibody dependent enhancement (ADE) in DENV infections occurs when a person with primary immunity is infected by a second, different DENV strain. Antibodies to Zika virus (ZIKV), which emerged in the Western Hemisphere in 2015, are cross reactive with DENV and theoretically could provoke ADE in a DENV naïve individual. CASE PRESENTATION: DENV infection was suspected in a child who had recently returned from a one-month stay in the Dominican Republic. The child presented with fever, vomiting, abdominal pain, and in hypovolemic shock. Volume and pressor resuscitation were unsuccessful, and the child died less than 24 h after hospitalization. Laboratory results suggested an early acute first DENV infection since serum, plasma, and spinal fluid had DENV1 detected by polymerase chain reaction (PCR), yet the serum lacked IgG antibodies to DENV nonstructural protein 1 (NS1) of all four DENV serotypes. This acute DENV infection occurred in the presence of a remote ZIKV infection as determined by antibodies to ZIKV NS1 envelope by multiplex microsphere immunoassay and an exceptionally high plaque reduction neutralization titer to ZIKV. ZIKV IgG avidity index was high, confirming a past infection. DENV1 RNA was detected in all ten organs and tissues examined by PCR. The severe and fatal complications reported here suggest that a remote ZIKV infection may provoke an exaggerated immune response leading to hypovolemic shock when primarily infected by DENV1. CONCLUSION: We report the first known patient in the United States with a rapidly progressive and fatal case of travel-associated DENV in which prior exposure to ZIKV likely played a role in triggering an ADE phenomenon. This association of prior ZIKV immunity and subsequent new dengue infection is a worrisome phenomenon and an important contribution to the body of knowledge on immunity to flaviviruses.

Comparative assessment for rat strain differences in metabolic profiles of 14 drugs in Wistar Han and Sprague Dawley hepatocytes.

Knowledge of inter-strain and inter-gender differences in drug metabolism studies is important for animal selection in pharmacokinetic and toxicological studies. The effects of rat strain and gender in in vitro metabolism were investigated in Sprague Dawley (SD) and Wister Han (WH) rats based on the hepatocyte metabolic profiles of 14 small molecule drugs. Similarities were found between the hepatocyte metabolic clearances of SD and WH strains, suggesting that only one strain can be confidently used for the evaluation of hepatic clearance. Neither strain of rat was preferable over the other to cover human metabolites. Higher similarities in metabolic pathways were found between the same gender than the same strain. Differences in metabolite identities, metabolite formation rates and potential biotransformation pathways were observed between SD and WH rat strains. Eleven metabolites from six drugs were "disproportionally" formed between SD and WH rats. The use of a specific rat strain model and gender for ADME and toxicity testing should, therefore, be carefully considered as metabolic profiles may differ, even though metabolic clearance was similar between SD and WH rats.

Thematic Analysis of Hospice Mentions in the Health Records of Veterans with Advanced Kidney Disease.

BACKGROUND: Patients with advanced kidney disease are less likely than many patients with other types of serious illness to enroll in hospice. Little is known about real-world clinical decision-making related to hospice for members of this population. METHODS: We used a text search tool to conduct a thematic analysis of documentation pertaining to hospice in the electronic medical record system of the Department of Veterans Affairs, for a national sample of 1000 patients with advanced kidney disease between 2004 and 2014 who were followed until October 8, 2019. RESULTS: Three dominant themes emerged from our qualitative analysis of the electronic medical records of 340 cohort members with notes containing hospice mentions: (1) hospice and usual care as antithetical care models: clinicians appeared to perceive a sharp demarcation between services that could be provided under hospice versus usual care and were often uncertain about hospice eligibility criteria. This could shape decision-making about hospice and dialysis and made it hard to individualize care; (2) hospice as a last resort: patients often were referred to hospice late in the course of illness and did not so much choose hospice as accept these services after all treatment options had been exhausted; and (3) care complexity: patients' complex care needs at the time of hospice referral could complicate transitions to hospice, stretch the limits of home hospice, and promote continued reliance on the acute care system. CONCLUSIONS: Our findings underscore the need to improve transitions to hospice for patients with advanced kidney disease as they approach the end of life.

The Role of Antibody Testing for SARS-CoV-2: Is There One?

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) brought with it rapid development of both molecular and serologic assays for identification of COVID-19 infections. While Food and Drug Administration (FDA) emergency use authorization (EUA) is required for clinical application of SARS-CoV-2 molecular tests, submission for EUA is currently a voluntary process for manufacturers of serologic assays. The absence of FDA oversight of serologic tests is concerning given that the commercially available serologic assays are highly variable, differing in their format, the antibody class detected, the targeted antigen, and the acceptable specimen types. An added complication is the lack of a clear understanding for how such assays should be utilized and what the reported results ultimately indicate or, perhaps more importantly, what they do not indicate. Here, we provide a brief summary of the performance of a number of serologic assays reported in the literature, comment on what we do and do not know regarding our immune response to SARS-CoV-2, and provide a number of scenarios for which serologic testing will play a role during our global response to this pandemic.

Experiences of US Nephrologists in the Delivery of Conservative Care to Patients With Advanced Kidney Disease: A National Qualitative Study.

RATIONALE & OBJECTIVE: It is relatively unusual for US patients with advanced chronic kidney disease (CKD) to forgo initiation of maintenance dialysis. Our objective was to describe practice approaches of US nephrologists who have provided conservative care for members of this population. STUDY DESIGN: Qualitative study using semi-structured interviews. SETTING & PARTICIPANTS: A national sample of 21 nephrologists experienced in caring for patients with advanced CKD who decided not to start dialysis. ANALYTICAL APPROACH: Grounded theory methods to identify dominant themes reflecting nephrologists' experiences with and approaches to conservative care for patients with advanced CKD. RESULTS: Nephrologists who participated in this study were primarily from academic practices (n=14) and urban areas (n=15). Two prominent themes emerged from qualitative analysis reflecting nephrologists' experiences with and approaches to conservative care: (1) person-centered practices, which described a holistic approach to care that included basing treatment decisions on what mattered most to individual patients, framing dialysis as an explicit choice, being mindful of sources of bias in medical decision making, and being flexible to the changing needs, values, and preferences of patients; and (2) improvising a care infrastructure, which described the challenges of managing patients conservatively within health systems that are not optimally configured to support their needs. Participating nephrologists described cobbling together resources, assuming a range of different health care roles, preparing patients to navigate health systems in which initiation of dialysis served as a powerful default, and championing the principles of conservative care among their colleagues. LIMITATIONS: The themes identified likely are not generalizable to most US nephrologists. CONCLUSIONS: Insights from a select group of US nephrologists who are early adopters of conservative care signal the need for a stronger cultural and health system commitment to building care models capable of supporting patients who choose to forgo dialysis.

Ethical Concerns in the Care of Patients with Advanced Kidney Disease: a National Retrospective Study, 2000-2011.

BACKGROUND: Understanding ethical concerns that arise in the care of patients with advanced kidney disease may help identify opportunities to support medical decision-making. OBJECTIVE: To describe the clinical contexts and types of ethical concerns that arise in the care of patients with advanced kidney disease. DESIGN: Retrospective cohort study. PARTICIPANTS: A total of 28,568 Veterans with advanced kidney disease between 2000 and 2009 followed through death or 2011. EXPOSURE: Clinical scenarios that prompted clinicians to consider an ethics consultation as documented in the medical record. MAIN MEASURES: Dialysis initiation, dialysis discontinuation, receipt of an intensive procedure during the final month of life, and hospice enrollment. KEY RESULTS: Patients had a mean age of 67.1 years, and the majority were male (98.5%) and white (59.0%). Clinicians considered an ethics consultation for 794 patients (2.5%) over a median follow-up period of 2.7 years. Ethical concerns involved code status (37.8%), dialysis (54.5%), other invasive treatments (40.6%), and noninvasive treatments (61.1%) and were related to conflicts between patients, their surrogates, and/or clinicians about treatment preferences (79.3%), who had authority to make healthcare decisions (65.9%), and meeting the care needs of patients versus obligations to others (10.6%). Among the 20,583 patients who died during follow-up, those for whom clinicians had considered an ethics consultation were less likely to have been treated with dialysis (47.6% versus 62.0%, adjusted odds ratio [aOR] 0.63, 95% CI 0.53-0.74), more likely to have discontinued dialysis (32.5% versus 20.9%, aOR 2.07, CI 1.61-2.66), and less likely to have received an intensive procedure in the last month of life (8.9% versus 18.9%, aOR 0.41, CI 0.32-0.54) compared with patients without documentation of clinicians having considered consultation. CONCLUSIONS: Clinicians considered an ethics consultation for patients with advanced kidney disease in situations of conflicting preferences regarding dialysis and other intensive treatments, especially when these treatments were not pursued.