Evaluation of the drug disposition of RO7049389 with in vitro data and human mass balance supported by physiologically based pharmacokinetic modelling.

AIMS: RO7049389 (linvencorvir) is a developmental oral treatment for chronic hepatitis B virus infection. The aim of this work was to conduct mass balance (MB) and absolute bioavailability (BA) analyses in healthy volunteers, alongside in vitro evaluations of the metabolism of RO7049389 and a major circulating active metabolite M5 in human hepatocytes, and physiologically based pharmacokinetic (PBPK) modelling to refine the underlying drug disposition paradigm. METHODS: Participants in the clinical study (MB: Caucasian, male, n = 6; BA: Caucasian and Asian, male and female, n = 16, 8 in each ethnic groups) received oral [14 C] or unlabelled RO7049389 (600/1000 mg) followed by 100 µg intravenous [13 C]RO7049389. Metabolic pathways with fractions metabolized-obtained from the in vitro incubation results of 10 µM [14 C]RO7049389 and 1 µM M5 with (long-term cocultured) human hepatocytes in the absence and presence of the cytochrome P450 3A4 (CYP3A4) inhibitor itraconazole-were used to complement the PBPK models, alongside the clinical MB and BA data. RESULTS: The model performance in predicting the pharmacokinetic profiles of RO7049389 and M5 aligned with clinical observations in Caucasians and was also successfully applied to Asians. Accordingly, the drug disposition pathways for RO7049389 were postulated with newly characterized estimates of the fractions: biliary excretion by P-glycoprotein (~41%), direct glucuronidation via uridine 5'-diphosphoglucuronosyltransferase 1A3 (~11%), hexose conjugation (~6%), oxidation by CYP3A4 (~28%) and other oxidation reactions (~9%). CONCLUSION: These results support the ongoing clinical development program for RO7049389 and highlight the broader value of PBPK and MB analyses in drug development.

Serious Underlying Medical Conditions and COVID-19 Vaccine Hesitancy: A Large Cross-Sectional Analysis from Australia.

As COVID-19 vaccinations became available and were proven effective in preventing serious infection, uptake amongst individuals varied, including in medically vulnerable populations. This cross-sectional multi-site study examined vaccine uptake, hesitancy, and explanatory factors amongst people with serious and/or chronic health conditions, including the impact of underlying disease on attitudes to vaccination. A 42-item survey was distributed to people with cancer, diabetes, or multiple sclerosis across ten Australian health services from 30 June to 5 October 2021. The survey evaluated sociodemographic and disease-related characteristics and incorporated three validated scales measuring vaccine hesitancy and vaccine-related beliefs generally and specific to their disease: the Oxford COVID-19 Vaccine Hesitancy Scale, the Oxford COVID-19 Vaccine Confidence and Complacency Scale and the Disease Influenced Vaccine Acceptance Scale-Six. Among 4683 participants (2548 [54.4%] female, 2108 [45.0%] male, 27 [0.6%] other; mean [SD] age, 60.6 [13.3] years; 3560 [76.0%] cancer, 842 [18.0%] diabetes, and 281 [6.0%] multiple sclerosis), 3813 (81.5%) self-reported having at least one COVID-19 vaccine. Unvaccinated status was associated with younger age, female sex, lower education and income, English as a second language, and residence in regional areas. Unvaccinated participants were more likely to report greater vaccine hesitancy and more negative perceptions toward vaccines. Disease-related vaccine concerns were associated with unvaccinated status and hesitancy, including greater complacency about COVID-19 infection, and concerns relating to vaccine efficacy and impact on their disease and/or treatment. This highlights the need to develop targeted strategies and education about COVID-19 vaccination to support medically vulnerable populations and health professionals.

Addressing Today's Absorption, Distribution, Metabolism, and Excretion (ADME) Challenges in the Translation of In Vitro ADME Characteristics to Humans: A Case Study of the SMN2 mRNA Splicing Modifier Risdiplam.

Small molecules that present complex absorption, distribution, metabolism, and elimination (ADME) properties can be challenging to investigate as potential therapeutics. Acquiring data through standard methods can yield results that are insufficient to describe the in vivo situation, which can affect downstream development decisions. Implementing in vitro-in vivo-in silico strategies throughout the drug development process is effective in identifying and mitigating risks while speeding up their development. Risdiplam (Evrysdi)-an orally bioavailable, small molecule approved by the US Food and Drug Administration and more recently by the European Medicines Agency for the treatment of patients ≥2 months of age with spinal muscular atrophy-is presented here as a case study. Risdiplam is a low-turnover compound whose metabolism is mediated through a non-cytochrome P450 enzymatic pathway. Four main challenges of risdiplam are discussed: predicting in vivo hepatic clearance, determining in vitro metabolites with regard to metabolites in safety testing guidelines, elucidating enzymes responsible for clearance, and estimating potential drug-drug interactions. A combination of in vitro and in vivo results was successfully extrapolated and used to develop a robust physiologically based pharmacokinetic model of risdiplam. These results were verified through early clinical studies, further strengthening the understanding of the ADME properties of risdiplam in humans. These approaches can be applied to other compounds with similar ADME profiles, which may be difficult to investigate using standard methods. SIGNIFICANCE STATEMENT: Risdiplam is the first approved, small-molecule, survival of motor neuron 2 mRNA splicing modifier for the treatment of spinal muscular atrophy. The approach taken to characterize the absorption, distribution, metabolism, and excretion (ADME) properties of risdiplam during clinical development incorporated in vitro-in vivo-in silico techniques, which may be applicable to other small molecules with challenging ADME. These strategies may be useful in improving the speed at which future drug molecules can be developed.

Doctors Routinely Share Health Data Electronically Under HIPAA, and Sharing With Patients and Patients' Third-Party Health Apps is Consistent: Interoperability and Privacy Analysis.

Since 2000, federal regulations have affirmed that patients have a right to a complete copy of their health records from their physicians and hospitals. Today, providers across the nation use electronic health records and electronic information exchange for health care, and patients are choosing digital health apps to help them manage their own health and health information. Some doctors and health systems have voiced concern about whether they may transmit a patient's data upon the patient's request to the patient or the patient's health app. This hesitation impedes shared information and care coordination with patients. It impairs patients' ability to use the state-of-the-art digital health tools they choose to track and manage their health. It undermines the ability of patients' family caregivers to monitor health and to work remotely to provide care by using the nearly unique capabilities of health apps on people's smartphones. This paper explains that sharing data electronically with patients and patients' third-party apps is legally consistent under the Health Insurance Portability and Accountability Act (HIPAA) with routine electronic data sharing with other doctors for treatment or with insurers for reimbursement. The paper explains and illustrates basic principles and scenarios around sharing with patients, including patients' third-party apps. Doctors routinely and legally share health data electronically under HIPAA whether or not their organizations retain HIPAA responsibility. Sharing with patients and patients' third-party apps is no different and should be just as routine.

Deploying Patient-Facing Application Programming Interfaces: Thematic Analysis of Health System Experiences.

BACKGROUND: Health systems have recently started to activate patient-facing application programming interfaces (APIs) to facilitate patient access to health data and other interactions. OBJECTIVE: This study sought to ascertain health systems' understanding, strategies, governance, and organizational infrastructure around patient-facing APIs, as well as their business drivers and barriers, to facilitate national learning, policy, and progress toward adoption. METHODS: We performed a content analysis of semistructured interviews with a convenience sample of 10 health systems known to be leading adopters of health technology, having either implemented or planning to implement patient-facing APIs. RESULTS: Of the 10 health systems, eight had operational patient-facing APIs, with organizational strategy driven most by federal policy, the emergence of Health Records on iPhone, and feelings of ethical obligation. The two priority use cases identified were enablement of a patient's longitudinal health record and digital interactions with the health system. The themes most frequently cited as barriers to the increased use of patient-facing APIs were security concerns, an immature app ecosystem that does not currently offer superior functionality compared with widely adopted electronic health record (EHR)-tethered portals, a lack of business drivers, EHR vendor hesitation toward data sharing, and immature technology and standards. CONCLUSIONS: Our findings reveal heterogeneity in health system understanding and approaches to the implementation and use of patient-facing APIs. Ongoing study, targeted policy interventions, and sharing of best practices appear necessary to achieve successful national implementation.

Predictors of ICU admission and long-term outcomes in overdose presentations to Emergency Department.

OBJECTIVE: To describe the characteristics of patients presenting to an Emergency Department (ED) following overdoses; to identify risk factors for intensive care unit (ICU) admission among these patients; and to identify the rate of mortality and repeat overdose presentations over four years. METHODS: Adult patients presenting to ED following drug overdose during 2014 were included. Data were collected from medical notes and hospital databases. RESULTS: During the study period, 654 patients presented to ED 800 times following overdose. Seventy-eight (9.8%) resulted in ICU admission, and 59 (7.4%) required intubation; 57.2% had no history of overdose presentations, and 72.9% involved patients with known psychiatric illness. Overdose of atypical antipsychotics (AAP), age and history of prior overdose independently predicted ICU admission. A third of patients (n = 196, 30%) had subsequent presentations to ED following overdose, in the four years from their index presentation, with an all-cause four-year mortality of 3.4% (n = 22). CONCLUSION: A history of overdose, use of AAP and older age were risk factors for ICU admission following ED presentations. Over a third of patients had repeat overdose presentation in the four-year follow-up with a mortality of 3.4%.

No Clinical Impact of CYP3A5 Gene Polymorphisms on the Pharmacokinetics and/or Efficacy of Maraviroc in Healthy Volunteers and HIV-1-Infected Subjects.

Maraviroc is a C-C chemokine receptor type-5 antagonist approved for the treatment of HIV-1. Previous studies show that cytochrome P450 3A5 (CYP3A5) plays a role in maraviroc metabolism. CYP3A5 is subject to a genetic polymorphism. The presence of 2 functional alleles (CYP3A5*1/*1) confers the extensive metabolism phenotype, which is rare in whites but common in blacks. The effect of CYP3A5 genotype on maraviroc and/or metabolite pharmacokinetics was evaluated in 2 clinical studies: a post hoc analysis from a phase 2b/3 study (NCT00098293) conducted in 494 HIV-1-infected subjects (study 1) in which the impact on maraviroc efficacy in 303 subjects was also assessed, and a study conducted in 47 healthy volunteers (study 2). In study 2 (NCT02625207), extensive metabolizers had 26% to 37% lower mean area under the concentration-time curve compared with poor metabolizers (no CYP3A5*1 alleles). This effect diminished to 17% in the presence of potent CYP3A inhibition. The effect of CYP3A5 genotype was greatest in the formation of the metabolite (1S,2S)-2-hydroxymaraviroc. In study 1, the CYP3A5*1/*1 genotype unexpectedly had higher maraviroc area under the curve predictions (20%) compared with those with no CYP3A5*1 alleles. The reason for this disparity remains unclear. The proportions of subjects with viral loads <50 and <400 copies/mL for maraviroc were comparable among all 3 CYP3A5 genotypes. In both studies maraviroc exposures were in the range of near-maximal viral inhibition in the majority of subjects. These results demonstrate that although CYP3A5 contributes to the metabolism of maraviroc, CYP3A5 genotype does not affect the clinical response to maraviroc in combination treatment of HIV-1 infection at approved doses.

Transitioning from a single-site pilot project to a state-wide regional telehealth service: The experience from the Victorian Stroke Telemedicine programme.

Scaling of projects from inception to establishment within the healthcare system is rarely formally reported. The Victorian Stroke Telemedicine (VST) programme provided a very useful opportunity to describe how rural hospitals in Victoria were able to access a network of Melbourne-based neurologists via telemedicine. The VST programme was initially piloted at one site in 2010 and has gradually expanded as a state-wide regional service operating with 16 hospitals in 2017. The aim of this paper is to summarise the factors that facilitated the state-wide transition of the VST programme. A naturalistic case-study was used and data were obtained from programme documents, e.g. minutes of governance committees, including the steering committee, the management committee and six working groups; operational and evaluation documentation, interviews and research field-notes taken by project staff. Thematic analysis was undertaken, with results presented in narrative form to provide a summary of the lived experience of developing and scaling the VST programme. The main success factors were attaining funding from various sources, identifying a clinical need and evidence-based solution, engaging stakeholders and facilitating co-design, including embedding the programme within policy, iterative evaluation including performing financial sustainability modelling, and conducting dissemination activities of the interim results, including promotion of early successes.

Metabolism, Excretion, and Pharmacokinetics of Selumetinib, an MEK1/2 inhibitor, in Healthy Adult Male Subjects.

PURPOSE: Selumetinib (AZD6244, ARRY-142886), an oral mitogen activated kinase 1/2 inhibitor, is in clinical development for the treatment of a variety of different tumor types. Herein, we report a study that determined the distribution, metabolism, and excretion of selumetinib in healthy male volunteers. METHODS: In this open-label, single-center, Phase I clinical trial, 6 subjects received a single 75-mg dose of [14C]-selumetinib. Blood and excreta samples were collected for pharmacokinetic and radiometric analyses. Tolerability monitoring was performed throughout the study. FINDINGS: The Cmax of plasma selumetinib was 1520 ng/mL at 1 hour postdose and declined with a t1/2 of 13.7 hours. Over a 216-hour postdose collection period, total dose recovery was 93% of the radioactive dose, with 59% recovered from feces and 33% from urine. Circulating drug-related material was primarily associated with plasma, with minimal distribution into red blood cells. Selumetinib was the major circulating drug-related component and accounted for 40% of the plasma radioactivity (mean of AUC0-72h pool). The major circulating metabolite (M2; accounting for 22% of the plasma radioactivity) resulted from multiple biotransformation pathways, including loss of the ethanediol moiety in combination with glucuronidation. A further 6 circulating metabolites were identified, each accounting for between 2% and 7% of plasma radioactivity. Selumetinib was a minor component in urine, accounting for ≤1% of the dose. M2 was the most abundant metabolite in urine, accounting for 10% of the dose, and there were 5 other metabolites accounting for between 1% and 10% of the dose. In feces, selumetinib accounted for a mean of 19% of the dose. Also present were 7 metabolites accounting for between 1% and 9% of the dose. The majority of the dose was recovered as metabolites, indicating that the liver is the major route of drug elimination. There were no tolerability concerns. IMPLICATIONS: The findings from this study will inform the label and will contribute to the understanding of the clinical pharmacology of selumetinib. ClinicalTrials.gov identifier: NCT01931761.

Electrothermal instability mitigation by using thick dielectric coatings on magnetically imploded conductors.

Recent experiments on Sandia's Z facility have confirmed simulation predictions of dramatically reduced instability growth in solid metallic rods when thick dielectric coatings are used to mitigate density perturbations arising from an electrothermal instability. These results provide further evidence that the inherent surface roughness as a result of target fabrication is not the dominant seed for the growth of magneto-Rayleigh-Taylor instabilities in liners with carefully machined smooth surfaces, but rather electrothermal instabilities that form early in the electrical current pulse as Joule heating melts and vaporizes the liner surface. These results suggest a new technique for substantially reducing the integral magneto-Rayleigh-Taylor instability growth in magnetically driven implosions, such as cylindrical dynamic material experiments and inertial confinement fusion concepts.

Case studies addressing human pharmacokinetic uncertainty using a combination of pharmacokinetic simulation and alternative first in human paradigms.

PF-184298 ((S)-2,3-dichloro-N-isobutyl-N-pyrrolidin-3-ylbenzamide) and PF-4776548 ((3-(4-fluoro-2-methoxy-benzyl)-7-hydroxy-8,9-dihydro-3H,7H-pyrrolo[2,3-c][1,7]naphthyridin-6-one)) are novel compounds which were selected to progress to human studies. Discordant human pharmacokinetic predictions arose from pre-clinical in vivo studies in rat and dog, and from human in vitro studies, resulting in a clearance prediction range of 3 to >20 mL min⁻¹ kg⁻¹ for PF-184298, and 5 to >20 mL min⁻¹ kg⁻¹ for PF-4776548. A package of work to investigate the discordance for PF-184298 is described. Although ultimately complementary to the human pharmacokinetic data in characterising the disposition of PF-184298 in humans, these data did not provide any further confidence in pharmacokinetic prediction. A fit for purpose human pharmacokinetic study was conducted for each compound, with an oral pharmacologically active dose for PF-184298, and an intravenous and oral microdose for PF-4776548. This provided a relatively low cost, clear decision making approach, resulting in the termination of PF-4776548 and further progression of PF-184298. A retrospective analysis of the data showed that, if the tools had been available at the time, the pharmacokinetics of PF-184298 in human could have been predicted from a population based simulation tool in combination with physicochemical properties and in vitro human intrinsic clearance.

The use of 96-well Scintiplates to facilitate definitive metabolism studies for drug candidates.

Semi-quantitative analysis of the drug-related components in biological samples collected during definitive metabolism studies using radiolabelled drug candidates is commonly achieved by HPLC profiling, using either on-line radiochemical detection or off-line liquid scintillation counting (LSC) following collection of the HPLC eluent into vials. However, although the use of LSC with vials has high sensitivity, the approach is time-consuming, laborious and destructive, whilst on-line detection methods are inappropriate for samples with low-levels of radioactivity (commonly the case with plasma samples). The use of 96-well microtitre plates (Scintiplates) for fraction collection during HPLC profiling provides a sensitive, effective and efficient alternative method for the semi-quantitative analysis of radiolabelled components in biological samples. Furthermore, the approach is non-destructive, such that subsequent identification of the isolated components can be achieved. Although the Scintiplate methodology is not appropriate for the analysis of excreta samples, where quenching of the radiochemical signal by endogenous components was observed, the approach was demonstrated to be valid for the relative quantification of [14C]-labelled material in plasma samples for all species investigated. In addition, good sensitivity was observed, with a counting efficiency of 79% for [14C], such that a drug-related component accounting for 10-15 dpm is quantifiable. The utility of the methodology for profiling circulating metabolites was demonstrated by the analysis of a rat plasma sample following oral administration of [14C]-UK-349,862. The Scintiplate approach and subsequent mass spectrometric analysis resulted in the relative quantitation and specific characterisation of circulating metabolites accounting for 93% of the total plasma radioactivity.