Investigation of Clinical Absorption, Distribution, Metabolism, and Excretion and Pharmacokinetics of the HIV-1 Maturation Inhibitor GSK3640254 Using an Intravenous Microtracer Combined with EnteroTracker for Biliary Sampling.

GSK3640254 is a next-generation maturation inhibitor in development for HIV-1 treatment, with pharmacokinetics (PK) supporting once-daily oral dosing in human. This open-label, nonrandomized, two-period clinical mass balance and excretion study was used to investigate the excretion balance, PK, and metabolism of GSK3640254. Five healthy men received a single intravenous microtracer of 100 µg [14C]GSK3640254 with a concomitant oral nonradiolabeled 200-mg tablet followed by an oral 85-mg dose of [14C]GSK3640254 14 days later. Complementary methods, including intravenous microtracing and accelerator mass spectrometry, allowed characterization of several parameters, including fraction absorbed, fraction escaping gut metabolism, hepatic extraction ratio, and renal clearance. Intravenous PK of GSK3640254 was characterized by low plasma clearance (1.04 l/h), moderate terminal phase half-life (21.7 hours), and low volume of distribution at steady state (28.7 L). Orally dosed GSK3640254 was absorbed (fraction absorbed, 0.26), with a high fraction escaping gut metabolism (0.898) and a low hepatic extraction ratio (0.00544), all consistent with low in vitro intrinsic clearance in liver microsomes and hepatocytes. No major metabolites in human plasma required further qualification in animal studies. Both unchanged parent GSK3640254 and its oxidative and conjugative metabolites were excreted into bile, with GSK3640254 likely subject to further metabolism through enterohepatic recirculation. Renal elimination of GSK3640254 as the parent drug or its metabolites was negligible, with >94% of total recovery of oral dose and >99% of the recovered radioactivity in feces. Altogether, the data suggest that systemically available GSK3640254 was slowly eliminated almost entirely by hepatobiliary secretion, primarily as conjugative and oxidative metabolites. SIGNIFICANCE STATEMENT: The combination of an intravenous 14C microtracer with duodenal bile sampling using EnteroTracker in a human absorption, distribution, metabolism, and excretion study enabled derivation of absorption and first-pass parameters, including fraction absorbed, proportion escaping first-pass extraction through the gut wall and liver, hepatic extraction, and other conventional clinical pharmacokinetic parameters. This approach identified hepatic metabolism and biliary excretion as a major elimination pathway for absorbed drug, which would be overlooked based solely on analyses of plasma, urine, and fecal matrices.

Pharmacokinetics and ADME Characterization of Intravenous and Oral [14C]-Linerixibat in Healthy Male Volunteers.

Linerixibat, an oral small-molecule ileal bile acid transporter inhibitor under development for cholestatic pruritus in primary biliary cholangitis, was designed for minimal absorption from the intestine (site of pharmacological action). This study characterized the pharmacokinetics, absorption, metabolism, and excretion of [14C]-linerixibat in humans after an intravenous microtracer concomitant with unlabeled oral tablets and [14C]-linerixibat oral solution. Linerixibat exhibited absorption-limited flip-flop kinetics: longer oral versus intravenous half-life (6-7 hours vs. 0.8 hours). The short intravenous half-life was consistent with high systemic clearance (61.9 l/h) and low volume of distribution (16.3 l). In vitro studies predicted rapid hepatic clearance via cytochrome P450 3A4 metabolism, which predicted human hepatic clearance within 1.5-fold. However, linerixibat was minimally metabolized in humans after intravenous administration: ∼80% elimination via biliary/fecal excretion (>90%-97% as unchanged parent) and ∼20% renal elimination by glomerular filtration (>97% as unchanged parent). Absolute oral bioavailability of linerixibat was exceedingly low (0.05%), primarily because of a very low fraction absorbed (0.167%; fraction escaping first-pass gut metabolism (fg) ∼100%), with high hepatic extraction ratio (77.0%) acting as a secondary barrier to systemic exposure. Oral linerixibat was almost entirely excreted (>99% recovered radioactivity) in feces as unchanged and unabsorbed linerixibat. Consistent with the low oral fraction absorbed and ∼20% renal recovery of intravenous [14C]-linerixibat, urinary elimination of orally administered radioactivity was negligible (<0.04% of dose). Linerixibat unequivocally exhibited minimal gastrointestinal absorption and oral systemic exposure. Linerixibat represents a unique example of high CYP3A4 clearance in vitro but nearly complete excretion as unchanged parent drug via the biliary/fecal route. SIGNIFICANCE STATEMENT: This study conclusively established minimal absorption and systemic exposure to orally administered linerixibat in humans. The small amount of linerixibat absorbed was eliminated efficiently as unchanged parent drug via the biliary/fecal route. The hepatic clearance mechanism was mispredicted to be mediated via cytochrome P450 3A4 metabolism in vitro rather than biliary excretion of unchanged linerixibat in vivo.

An Innovative Approach to Characterize Clinical ADME and Pharmacokinetics of the Inhaled Drug Nemiralisib Using an Intravenous Microtracer Combined with an Inhaled Dose and an Oral Radiolabel Dose in Healthy Male Subjects.

An innovative open-label, crossover clinical study was used to investigate the excretion balance, pharmacokinetics, and metabolism of nemiralisib-an inhaled phosphoinositide 3-kinase delta inhibitor being developed for respiratory diseases. Six healthy men received a single intravenous microtracer of 10 µg [14C]nemiralisib with a concomitant inhaled nonradiolabeled 1000 µg dose followed by an oral 800 µg dose of [14C]nemiralisib 14 days later. Complementary methods including accelerator mass spectrometry allowed characterization of a range of parameters including oral absorption (Fabs), proportion of nemiralisib escaping gut wall metabolism (Fg), hepatic extraction (Eh), fraction of dose absorbed from inhaled dose (Flung), and renal clearance. Intravenous pharmacokinetics of nemiralisib were characterized by low blood clearance (10.0 l/h), long terminal half-life (55 hours), and high volume of distribution at steady state (728 l). Nemiralisib exhibited moderate inhaled and oral bioavailability (38% and 35%) while Flung was 29%. Absorption and first-pass parameters were corrected for blood renal clearance and compared with values without correction. Any swallowed nemiralisib was relatively well absorbed (Fabs, 0.48) with a high fraction escaping gut wall metabolism and low extraction by the liver (Fg and Eh being 0.83 and 0.10, respectively). There were no major human plasma metabolites requiring further qualification in animal studies. Both unchanged nemiralisib and its oxidative/conjugative metabolites were secreted in bile, with nemiralisib likely subject to further metabolism through enterohepatic recirculation. Direct renal clearance and metabolism followed by renal clearance were lesser routes of elimination. SIGNIFICANCE STATEMENT: A number of innovative features have been combined into one small clinical study enabling a comprehensive description of the human pharmacokinetics and metabolism of an inhaled molecule. Design elements included an intravenous 14C tracer administration concomitant with an inhalation dose that enabled derivation of parameters such as fraction absorbed (Fabs), the proportion of drug escaping first-pass extraction through the gut wall and liver (Fg and Fh) and hepatic extraction (Eh). Entero-test bile sampling enabled characterization of biliary elimination pathways.

A human microdose study of the antimalarial drug GSK3191607 in healthy volunteers.

AIMS: GSK3191607, a novel inhibitor of the Plasmodium falciparum ATP4 (PfATP4) pathway, is being considered for development in humans. However, a key problem encountered during the preclinical evaluation of the compound was its inconsistent pharmacokinetic (PK) profile across preclinical species (mouse, rat and dog), which prevented reliable prediction of PK parameters in humans and precluded a well-founded assessment of the potential for clinical development of the compound. Therefore, an open-label microdose (100 µg, six subjects) first time in humans study was conducted to assess the human PK of GSK3191607 following intravenous administration of [14C]-GSK3191607. METHODS: A human microdose study was conducted to investigate the clinical PK of GSK3191607 and enable a Go/No Go decision on further progression of the compound. The PK disposition parameters estimated from the microdose study, combined with preclinical in vitro and in vivo pharmacodynamic parameters, were all used to estimate the potential efficacy of various oral dosing regimens in humans. RESULTS: The PK profile, based on the microdose data, demonstrated a half-life (~17 h) similar to other antimalarial compounds currently in clinical development. However, combining the microdose data with the pharmacodynamic data provided results that do not support further clinical development of the compound for a single dose cure. CONCLUSIONS: The information generated by this study provides a basis for predicting the expected oral PK profiles of GSK3191607 in man and supports decisions on the future clinical development of the compound.

Metabolism and disposition of vilanterol, a long-acting ß(2)-adrenoceptor agonist for inhalation use in humans.

The metabolism and disposition of vilanterol, a novel long-acting ß(2)-adrenoceptor agonist (LABA) for inhalation use, was investigated after oral administration in humans. Single oral administrations of up to 500 µg of vilanterol were shown to be safe and well tolerated in two clinical studies in healthy men. In a human radiolabel study, six healthy men received a single oral dose of 200 µg of [(14)C]vilanterol (74 kBq). Plasma, urine, and feces were collected up to 168 hours after the dose and were analyzed for vilanterol, metabolites, and radioactivity. At least 50% of the radioactive dose was orally absorbed. The primary route of excretion of drug-related material was via O-dealkylation to metabolites, which were mainly excreted in urine. Vilanterol represented a very small percentage (<0.5%) of the total drug-related material in plasma, indicative of extensive first-pass metabolism. Circulating metabolites resulted mainly from O-dealkylation and exhibited negligible pharmacologic activity. The therapeutic dose level for vilanterol is 25 µg by the inhalation route. At this low-dose level, the likelihood of pharmacologically inactive metabolites causing unexpected toxicity is negligible. In addition to providing an assessment of the disposition of vilanterol in human, this work highlights a number of complexities associated with determining human absorption, distribution, metabolism, and excretion (ADME) for inhaled molecules--mainly related to the low chemical doses and complications associated with the inhalation route of administration.

Investigation of the human metabolism and disposition of the prolyl hydrolase inhibitor daprodustat using IV microtracer with Entero-Test bile string.

Daprodustat is an oral small molecule hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor (PHI) approved in Japan and the United States for the treatment of anemia associated with chronic kidney disease. This phase 1, nonrandomized, 2-period, crossover study in 6 healthy men characterized and quantified the metabolites generated after a microtracer IV infusion of 50 µg (125 nCi) [14 C]-daprodustat administered concomitantly with a nonradiolabeled therapeutic dose of a 6-mg daprodustat tablet, followed by a single oral solution dose of 25 mg (62.5 µCi) [14 C]-daprodustat. High-performance liquid chromatography (HPLC) coupled with radioactivity detection (TopCount or AMS) and HPLC-tandem mass spectrometry (HPLC-MSn ) were used for quantitative measurement and structural identification of radioactive metabolites in plasma, urine, feces, and bile. Following oral administration of [14 C]-daprodustat, unchanged daprodustat was the principal circulating drug-related component, accounting for 40% of plasma radioactivity. Predominant oxidative metabolites M2, M3, M4, and M13 individually represented 6-8% of the plasma radioactivity and together accounted for the majority of radioactivity in urine and feces (53% in both matrices; 12% and 41% of dose, respectively). Unchanged daprodustat was not detected in urine and was only 0.7% of total radioactivity in feces (<0.5% of dose), with the remainder of the dose accounted for by oxidative metabolites. The radio-metabolic profile of duodenal bile following IV infusion of [14 C]-daprodustat was similar to that observed in feces after oral administration. The data suggested that oral daprodustat was extensively absorbed, cleared exclusively by oxidative metabolism, and eliminated via hepatobiliary (primary) and urinary (secondary) excretion.

Low-wage migrant workers during coronavirus disease 2019: a social determinants analysis.

The severe acute respiratory syndrome coronavirus 2 pandemic has had disproportionate effects on economically and socially marginalized people. We explore the effects on low-wage migrant workers (migrant workers) in three countries: Singapore, South Korea and Brazil, through the lens of the social determinants of health. Our analysis shows that governments missed key opportunities to mitigate pandemic risks for migrant workers. Government measures demonstrate potential for effective and sustainable policy reform, including universal and equitable access to healthcare, social safety nets and labour rights for migrant workers-key concerns of the Global Compact for Migration. A whole-of-society and a whole-of-government approach with Health in All Policies, and migrant worker frameworks developed by the World Health Organization could be instrumental. The current situation indicates a need to frame public health crisis responses and policies in ways that recognize social determinants as fundamental to health.

Clinical Pharmacokinetics of Daprodustat: Results of an Absorption, Distribution, and Excretion Study With Intravenous Microtracer and Concomitant Oral Doses for Bioavailability Determination.

Daprodustat, an oral hypoxia-inducible factor prolyl hydroxylase inhibitor, is being investigated for treatment of anemia in chronic kidney disease. This phase 1, nonrandomized, 2-period, crossover study in 6 healthy men characterized the absorption, distribution, and excretion of daprodustat when administered as oral and intravenous (IV) doses of unlabeled and radiolabeled daprodustat ([14 C]-GSK1278863). Tolerability and pharmacokinetic properties of daprodustat, and its 6 metabolites in the systemic circulation, were also evaluated. The mean recovery of radiolabeled daprodustat was ≈95% by day 5, with the majority in feces and minor renal elimination, indicating that daprodustat and metabolites are primarily eliminated via hepatobiliary and fecal routes. Approximately 40% of total circulating radioactivity in plasma following both IV and oral administration was daprodustat; thus, 60% was attributed to metabolites. It was estimated that ≈80% of daprodustat was absorbed across the gastrointestinal tract, and ≈18% cleared by hepatic extraction. Pharmacokinetics were essentially dose proportional, with moderate (≈66%) oral tablet bioavailability. Following IV administration, daprodustat plasma clearance (19.3 L/h) and volume of distribution (14.6 L) were low, suggesting low tissue distribution outside systemic circulation with likely low penetration into tissues. Daprodustat was generally well tolerated, with no deaths or serious or significant adverse events reported.

Sudden cardiac death and kidney health related problems among Nepali migrant workers in Malaysia.

This paper reports on a consultation meeting that discussed two emerging health issues of Nepali migrant workers in Malaysia and the ways they can be addressed. Primarily, it focused on the issue of sudden cardiac deaths of Nepali migrant workers in Malaysia. This issue has been raised internationally by both scientific and media in the recent years. Secondly, it discussed kidney health related problem among Nepali migrant workers which has caught the attention of Nepali media recently. The meeting was organized in Kuala Lumpur, Malaysia on 19th April, 2019 where twenty people including health researchers, representatives of migrant related national and international organizations, and Nepali migrant workers participated. The meeting concluded that three types of data collection are needed: (1) good record of deaths, if at possible proper post-mortems; (2) a verbal autopsy tool to help identify underlying causes ; and qualitative research into kidney related problems.

Exploratory Study on Occupational Health Hazards among Health Care Workers in the Philippines.

BACKGROUND AND PURPOSE: Healthcare workers are prone to occupational hazards. The study aims to identify the occupational health hazards among healthcare workers in the Philippines and its essential relevant developmental framework. This article evolved on the responses of participants on how they can improve strategies and barriers for healthcare workers to comply with Occupational Health and Safety (OSH). METHODS: A qualitative study design in which 15 healthcare workers from nurses (4), pharmacists (3), medical technologies (4) and medical doctors (4) participated: two focus group of three to four participants each and eight in-depth interviews. The thematic sessions were identified, including occupational health and safety policy implementations, hazards experiences, barriers, and strategies for quality improvement for OSH. Focus groups and interviews using transcript-based analysis were identified relating to emerging themes on the challenges they had experienced while accessing provisions of OSH in their workplace. RESULTS: Majority of the participants revealed the existence of policy on Occupational Health and Safety (provisions, guidelines and regulations on OHS from the government) and mentioned that there were limited OHS officers to supervise the healthcare workers in their workplace. Some have limited accessibility to the requirements of the implementation of OHS (free facemasks, gloves, disinfectants, machines, OSH staff, etc.) among healthcare workers, while the workload of the staff in the implementation of OHS in the workplace gradually increased. The results indicated that the respondents were knowledgeable in the implementation of OHS in the workplace, and that there was no existing ASEAN framework on the protection and promotion of the rights of healthcare workers in their workplace. Facilities need to improve health assessment, and to ensure constant evaluation of the existing laws for healthcare workers (quality assurance of existing policies) in their working areas. Direct access to OSH officers, occupational hazards education, emergency contact etc. must be improved. Adherence must be strengthened to fully comply with the OHS standards. CONCLUSION: The researchers inferred that issues and concerns regarding compliance on provisions of occupational health and safety among health care workers must be properly addressed through immediate monitoring and reevaluation of personnel in terms of their knowledge and practices in OHS. Barriers and challenges have been identified in the study that can lead to improved compliance among healthcare workers in regards to OHS.

Pharmacokinetics, Excretion, and Mass Balance of [14 C]-Batefenterol Following a Single Microtracer Intravenous Dose (Concomitant to an Inhaled Dose) or Oral Dose of Batefenterol in Healthy Men.

Inhaled batefenterol is an investigational bifunctional molecule for the treatment of chronic obstructive pulmonary disease. The excretion balance and pharmacokinetics of batefenterol using [14 C]-radiolabeled drug administered orally and as intravenous (IV) infusion were assessed. In this 2-period, open-label study, 6 healthy male subjects received a single IV microtracer 1-hour infusion of 4 µg [14 C]-batefenterol concomitant with inhaled nonradiolabeled batefenterol (1200 µg) followed by oral [14 C]-batefenterol (200 µg) in period 2 after a 14-day washout. The primary end points included: the area under the concentration-time curve from time zero to last time of quantifiable concentration (AUC0-t ); maximum observed concentration (Cmax ); and time of occurrence of maximum observed concentration. Following IV administration, the geometric mean AUC0-t of [14 C]-batefenterol was 121.9 pgEq • h/mL; maximum observed concentration and time of occurrence of maximum observed concentration were 92.7 pgEq/mL and 0.8 hours, respectively; absolute oral bioavailability was 0.012%. The mean AUC0-t ratio indicated that [14 C]-batefenterol accounted for 85% of total circulating radioactivity in the plasma initially and declined rapidly following IV administration, but only ∼0.2% of total circulating radioactivity following oral administration. Cumulative mean recovery of total radioactive [14 C]-batefenterol in urine and feces was 6.31% and 77.6%, respectively. Overall, batefenterol exhibited low systemic bioavailability after inhaled and oral administration, and high fecal excretion and low urinary excretion following IV and oral administration.