Clinical assessment of gepotidacin (GSK2140944) as a victim and perpetrator of drug-drug interactions via CYP3A metabolism and transporters.

Gepotidacin is a novel triazaacenaphthylene antibiotic in phase III development. Based on nonclinical in vitro characterization of gepotidacin metabolism, two phase I studies were conducted in healthy participants to investigate clinical drug-drug interactions (DDIs). We assessed gepotidacin as a DDI victim with a potent cytochrome P450 (CYP) 3A4/P-glycoprotein (P-gp) inhibitor (itraconazole), potent CYP3A4 inducer (rifampicin), and nonspecific organic cation transporter (OCT)/multidrug and toxic extrusion transporter (MATE) renal transport inhibitor (cimetidine) via single doses of gepotidacin before and after co-administration with multiple doses of the modulator drugs. Gepotidacin DDI perpetrator potential for P-gp inhibition (digoxin) and CYP3A4 inhibition (midazolam) was evaluated via single doses of the two-drug cocktail without and with gepotidacin. The DDI magnitudes were interpreted based on area under the concentration-time curve (AUC). A weak DDI (AUC increase 48%-50%) was observed for gepotidacin co-administered with itraconazole. A clinically significant decrease in gepotidacin plasma AUC (52%) was observed with rifampicin coadministration, indicating a moderate DDI. There was no DDI for gepotidacin with cimetidine; a unique biomarker approach showed increased serum creatinine (24%), decreased renal clearance of creatinine (21%), and N1-methylnicotinamide (39%), which confirmed extensive MATE inhibition and partial OCT2 inhibition. Gepotidacin was not a P-gp DDI perpetrator, although the maximum plasma concentration of digoxin increased (53%) and is potentially clinically relevant given its narrow therapeutic index. Gepotidacin demonstrated weak CYP3A4 inhibition with midazolam (<2-fold AUC increase). There were no new safety-risk profile findings. These results will inform the safe and efficacious clinical use of gepotidacin when co-administered with other drugs.

Pharmacokinetic, Safety, and Tolerability Evaluations of Gepotidacin (GSK2140944) in Healthy Japanese Participants.

Gepotidacin is a novel, bactericidal, first-in-class triazaacenaphthylene antibiotic in late-phase development for uncomplicated urinary tract infection and uncomplicated urogenital gonorrhea. Two clinical studies were conducted to assess the pharmacokinetics (PK) and interethnic comparisons of oral gepotidacin (free-base and to-be-marketed mesylate formulations) administered as single doses ranging from 1500 to 3000 mg in fed and fasted states, and as 2 × 3000-mg doses given 12 hours apart under fed conditions in healthy participants of Japanese ancestry. Dose proportionality was observed in plasma exposures, and comparable area under the concentration-time curve (AUC) and maximum concentration were observed in fed and fasted states. Interethnic comparisons for Japanese versus non-Japanese participant data showed slightly higher plasma maximum concentration (7%-30%) yet similar plasma AUCs; slightly lower urine AUCs (11%-18%) were observed. The slightly higher plasma exposures in healthy Japanese versus White participants in the same study were attributed to lower mean body weights (64 kg versus ≈80 kg). Adverse events were primarily gastrointestinal, and when administered with food, gastrointestinal tolerability was improved. Overall, the gepotidacin PK and safety-risk profiles in healthy Japanese support potential evaluation of the global clinical doses in future studies.

Identification of potential risk factors for the poor prognosis of neonatal sepsis.

Background and aim: Risk factor-based approach is one of the best approaches employed by middle income countries which are not well facility driven for any disease management. Thus, through this approach, we aim to identify the potential risk factors responsible for the poor outcome in neonatal sepsis. Methods: A case control was conducted retrospectively with neonates admitted to Neonatal Intensive Care Unit during January 2012 to December 2016. Cases were identified using ICD-10 Code from inpatient medical records and demographic, maternal and neonatal details were collected from the medical files. Logistic regression was performed to identify the risk factors associated with mortality in neonatal sepsis. Results: A total of 613 neonates were found to have culture positive sepsis from the 4690 neonates admitted in the Neonatal Intensive Care Unit (NICU). There was a total of 831 episodes in the 613 neonates. The mortality rate in neonates with sepsis was found to be 25.4%. Extremely low birth weight (OR 6.171, CI 3.475-10.957), extreme preterm (OR 5.761, CI 2.612-12.708), very preterm (OR 2.548, CI 1.607-4.042), preeclampsia (OR 1.671, CI 1.091-2.562), acute renal failure (OR 4.939, CI-2.588-9.426), coagulopathy (OR 2.211, CI-1.486-3.289), septic shock (OR 173.522, CI-23.642-1273.59), thrombocytopenia (OR 5.231, CI-3.310-8.268), leukopenia (OR 2.422, CI- 1.473-3.984), CRP > 24 (OR 2.099, CI-1.263-3.487) and abnormal absolute neutrophil count (OR 2.108, CI-1.451-3.062) were some of the significant predictors, identified through risk-based approach, in assessing mortality in neonatal sepsis. Conclusion: Risk-based approach applied was successful in determining plausible important predictors such like extreme low birth weight, extreme preterm, resistance against gram negative infections, preeclampsia, septic shock, hypotension, leukopenia, neutropenia, thrombocytopenia in predicting mortality in neonatal sepsis. These potential risk factors, identified through risk- based approach, can play a pivotal role in assisting clinician to make appropriate and judicious decision.

Pharmacokinetics, safety, and tolerability of gepotidacin administered as single or repeat ascending doses, in healthy adults and elderly subjects.

Gepotidacin, a novel, first-in-class triazaacenaphthylene antibiotic, inhibits bacterial DNA replication by a distinct mechanism of action. We report the pharmacokinetics (PKs), safety, and tolerability of gepotidacin following single or multiple ascending doses. Studies 1 and 2 were randomized, single-blind, placebo-controlled trials in healthy adults aged 18-60 years, who received single (study 1 [NCT02202187]; 100-3000 mg) or repeat (study 2 [NCT01706315]; 400 mg twice daily to 2000 mg thrice daily) ascending doses of gepotidacin. Study 3 (NCT02045849) was an open-label, three-part, study in healthy adults; here, we report on part 3, a two-period, repeat-dose, crossover study. Healthy elderly participants received repeat 1500 mg gepotidacin twice daily with or without a moderate-fat meal. Primary end points were PKs (studies 1 and 2) and safety (studies 1 and 3 part 3). Gepotidacin PK parameters were comparable across all ages and were dose proportional. In all studies, gepotidacin was readily absorbed with median time to maximum concentration observed ranging from 1.0 to 4.0 h across all doses. Median apparent terminal phase half-life was consistent across studies and doses (range: 5.97-19.2 h). Steady-state was achieved following repeated dosing for 3-5 days; gepotidacin PK parameters were time invariant after repeated oral dosing. A moderate-fat meal did not affect gepotidacin PK parameters. Gepotidacin was generally well-tolerated, with no drug-related serious adverse events reported. Collectively, these PK and safety data across a wide range of doses in healthy participants aged greater than or equal to 18 years support the development of gepotidacin in further clinical studies.

Antiseizure medications and oral contraceptives: Impact of enzyme inducers on pregnancy outcomes and costs.

PURPOSE: To show the impact of drug-drug interactions (DDIs) associated with co-administration of enzyme-inducing (EI) antiseizure medications and oral contraceptives (OCs) on the annual number of unintended pregnancies, their outcomes, and their associated costs in the United States (US). METHODS: A Microsoft Excel pregnancy-outcomes model was developed to determine the impact of DDIs in women who take an OC as well as an EI antiseizure medication known to lower the effectiveness of the OC in preventing pregnancy. The model compared the number of unintended pregnancies, the expected pregnancy outcomes, and associated costs in women taking an OC and an EI medication with a matched cohort of women who took an OC and an enzyme-neutral (EN) antiseizure medication that is known not to interact with OCs. The model perspectives were patients and third-party payers in the US. Unintended pregnancy rates, pregnancy outcomes, and cost inputs for the model were taken from published studies. RESULTS: The results of the analysis showed an estimated increase in the annual number of unintended pregnancies in the US of 503 (a change from 1151 to 1654), an increase of 44.7%, for the estimated 71,922 women currently taking an OC plus an EI medication in the US when compared with a matched cohort taking an OC plus an EN medication. This resulted in an estimated annual healthcare cost increase of $3 million, which is an increase of 5.5% in the annual costs for contraception and pregnancy care. A scenario analysis showed that the annual number of unintended pregnancies could be lower (575 vs 1654) for a matched cohort of women taking EI medications and using a copper intrauterine device, a highly effective and nonhormonal form of contraception, rather than an OC. CONCLUSIONS: Physicians treating women of reproductive age for epilepsy who wish to avoid pregnancy should consider the potential for DDIs that might result in unintended pregnancies. Thus, physicians should alert women using EI medications for epilepsy control to the increased potential for unintended pregnancies if they use OCs for contraception.

Development of a pharmacoeconomic registry: an example using hormonal contraceptives.

BACKGROUND: Disease-specific registries, documenting costs and probabilities from pharmacoeconomic studies along with health state utility values from quality-of-life studies could serve as a resource to guide researchers in evaluating the published literature and in the conduct of future economic evaluations for their own research. Registries cataloging economic evaluations currently exist, however they are restricted by the type of economic evaluations they include. There is a need for intervention-specific registries, that document all types of complete and partial economic evaluations and auxiliary information such as quality of life studies. The objective of this study is to describe the development of a pharmacoeconomic registry and provide best practices using an example of hormonal contraceptives. METHODS: An expert panel consisting of researchers with expertise in pharmacoeconomics and outcomes research was convened and the clinical focus of the registry was finalized after extensive discussion. A list of key continuous, categorical and descriptive variables was developed to capture all relevant data with each variable defined in a data dictionary. A web-based data collection tool was designed to capture and store the resulting metadata. A keyword based search strategy was developed to retrieve the published sources of literature. Finally, articles were screened for relevancy and data was extracted to populate the registry. Expert opinions were taken from the panel at each stage to arrive at consensus and ensure validity of the registry. RESULTS: The registry focused on economic evaluation literature of hormonal contraceptives used for contraception. The registry consisted of 65 articles comprising of 22 cost-effectiveness analyses, 9 cost-utility analyses, 7 cost-benefit analyses, 1 cost-minimization, 14 cost analyses, 10 cost of illness studies and 2 quality of life studies. The best practices followed in the development of the registry were summarized as recommendations. The completed registry, data dictionary and associated data files can be accessed in the supplementary information files. CONCLUSION: This registry is a comprehensive database of economic evaluations, including costs, clinical probabilities and health-state utility estimates. The collated data captured from published information in this registry can be used to identify trends in the literature, conduct systematic reviews and meta-analysis and develop novel pharmacoeconomic models.

Quantifying the economic burden of unintended pregnancies due to drug-drug interactions with hormonal contraceptives from the United States payer perspective.

Background: In the United States of America (USA), nearly 10 million women use oral contraceptives (OCs). Concomitant administration of certain medications can result in contraceptive failure, and consequently unintended pregnancies due to drug-drug interactions (DDIs). The objective of this analysis was to estimate the economic impact of unintended pregnancies due to DDIs among women of reproductive age using an OC alone or in combination with an enzyme inducer co-medication in the USA from a payer perspective. Methods: A Markov model using a cohort of 1,000 reproductive-age women was developed to estimate costs due to contraceptive failure for OC alone versus OC with concomitant enzyme inducer drugs. All women were assumed to begin an initial state, continuing until experiencing an unintended pregnancy. Unintended pregnancies could result in birth, induced abortion, spontaneous abortion, or ectopic pregnancy. The cohort was analyzed over a time horizon of 1 year with a cycle length of 1 month. Estimates of costs and probabilities of unintended pregnancy outcomes were obtained from the literature. Probabilities from the Markov cohort trace was used to estimate number of pregnancy outcomes. Results: On average, enzyme inducers resulted in 20 additional unintended pregnancies with additional unadjusted and adjusted costs median (range) of USD136,304 (USD57,436-USD320,093) and USD65,146 (USD28,491-USD162,635), respectively. The major component of the direct cost is attributed to the cost of births. Considering the full range of events, DDIs with enzyme inducers could result in 16-25 additional unintended pregnancies and total unadjusted and adjusted costs ranging between USD46,041 to USD399,121 and USD22,839 to USD202,788 respectively. Conclusion: The direct costs associated with unintended pregnancies due to DDIs may be substantial and are potentially avoidable. Greater awareness of DDI risk with oral contraceptives among payers, physicians, pharmacists and patients may reduce unintended pregnancies in at-risk populations.

Incorporating Pharmacometrics into Pharmacoeconomic Models: Applications from Drug Development.

Pharmacometrics is the science of quantifying the relationship between the pharmacokinetics and pharmacodynamics of drugs in combination with disease models and trial information to aid in drug development and dosing optimization for clinical practice. Considering the variability in the dose-concentration-effect relationship of drugs, an opportunity exists in linking pharmacokinetic and pharmacodynamic model-based estimates with pharmacoeconomic models. This link may provide early estimates of the cost effectiveness of drug therapies, thus informing late-stage drug development, pricing, and reimbursement decisions. Published case studies have demonstrated how integrated pharmacokinetic-pharmacodynamic-pharmacoeconomic models can complement traditional pharmacoeconomic analyses by identifying the impact of specific patient sub-groups, dose, dosing schedules, and adherence on the cost effectiveness of drugs, thus providing a mechanistic basis to predict the economic value of new drugs. Greater collaboration between the pharmacoeconomics and pharmacometrics community can enable methodological improvements in pharmacokinetic-pharmacodynamic-pharmacoeconomic models to support drug development.

Utility of Physiologically Based Pharmacokinetic Modeling in Point-of-Care Decisions: An Example Using Digoxin Dosing in Continuous Venovenous Hemodiafiltration.

We describe the case of a patient on continuous venovenous hemodiafiltration with atrial fibrillation with rapid ventricular response and hypotension requiring vasopressor use, which warranted digoxin therapy. In the absence of guidelines specifying appropriate digoxin dosing in patients undergoing continuous venovenous hemodiafiltration, anecdotal evidence-guided digoxin dosing was performed for this patient using plasma digoxin concentration-based therapeutic drug monitoring. We use this case to demonstrate the potential role of physiologically based pharmacokinetic modeling in assisting therapeutic decision making.

Diversity in the Era of Precision Medicine - From Bench to Bedside Implementation.

Recent evidence shows how patients' unique genetic makeup can affect disease outcomes and the increasing availability of targeted treatments promises a future in health care, whereby treatments will be tailored to individual needs. This article reports on the topics discussed at the 13th Annual Texas Conference on Health Disparities, organized by the Texas Center for Health Disparities at the University of North Texas Health Science Center; the meeting focused on the theme, "Diversity in the Era of Precision Medicine" and was held during June 2018 in Fort Worth, Texas. The primary focus of this conference, which brought together clinical and basic scientists, was on the inclusion of diversity in precision medicine to bridge the gap in health disparities. Here, we present the highlights of the conference that include the potential application of precision medicine at the population level, the effects of precision medicine and direct-to-consumer testing on health disparities, genetic basis of health disparities, pharmacogenomics, and strategies to enhance participation of under-represented populations in precision medicine. Furthermore, we conclude with recommendations for future implementation, including how to mitigate disparities in genomics services and enhance participation of diverse groups in clinical trials.

Population Pharmacokinetics of Pemetrexed in Adult Non-Small Cell Lung Cancer in Indian Patients.

The objective of the study was to develop a population pharmacokinetic model of pemetrexed and identify factors contributing to variability in exposure in Indian patients. Plasma samples were obtained from a cohort of 85 patients following 500 mg/m2 intravenous infusion and population pharmacokinetic analysis was performed using NONMEM (version 7.3.0). The stochastic approximation expectation maximization method was used to estimate parameters. The full covariate model approach was used by specifying clinically meaningful covariates a priori. Credible intervals obtained using Markov chain Monte Carlo Bayesian analysis were used to reduce the full covariate model by eliminating the covariates whose CI included the null. Model qualification was performed using visual predictive check and bootstrap. The final population parameter estimates and relative standard error for clearance (CL) was 3.3 L/h (10.8), central volume of distribution (V1) was 5.2 L (7.8), peripheral volume of distribution (V2) was 5.9 L (14.5) and intercompartmental clearance (Q) was 6.8 L/h (14.3). A large between-subject variability (50%-108% coefficient of variation) was observed in pharmacokinetic parameters. The percent coefficient of variation for the area under the plasma concentration-time curve from time zero to infinity was 72% and for maximum concentration was 68.25%. Diagnostic plots showed no major bias in the model. The final model included V1, V2, and Q scaled to body surface area raised to a fixed exponent of 1. Creatinine clearance and sex on clearance and albumin on V1 were statistically significant covariates based on Bayesian credible interval. However, traditional bootstrap resulted in a 95% confidence interval of the sex effect parameter including null. Given the size and nonsignificant sex effect in traditional bootstrap, it is considered clinically not significant.

Comparison of Various Severity Assessment Scoring Systems in Patients with Sepsis in a Tertiary Care Teaching Hospital.

BACKGROUND: Sepsis is a complex condition defined by the systemic response to infection. Severity assessment scoring systems are used to aid the physician in deciding whether aggressive treatment is needed or not. In this study, various severity assessment scoring systems, namely Acute Physiology and Chronic Health Evaluation II (APACHE II), Rapid Emergency Medicine Score (REMS), Sequential Organ Failure Assessment (SOFA), Multiple Organ Dysfunction Score (MODS), Predisposition, Infection, Response, and Organ Dysfunction (PIRO), and Mortality in Emergency Department Sepsis (MEDS), were compared to assess their sensitivity and specificity. MATERIALS AND METHODS: A prospective cohort study was conducted over 6 months. The study was conducted in the intensive care unit (ICU) of a tertiary care teaching hospital. All patients above 18 years of age with confirmed sepsis diagnosis and a well-defined outcome were included in the study. RESULTS: A total of 193 patients were included in the study. The mean age was 57.2 ± 15.3 (mean ± standard deviation) years. Majority of the patients were male, 125 (64.76%). Overall mortality was 108 (55.9%). The calculated area under the receiver operating characteristic curve was 0.86 (95% confidence interval [CI]: 0.80-0.90) for APACHE II, 0.81 (95% CI: 0.75-0.87) for REMS, 0.80 (95% CI: 0.74-0.86) for SOFA, 0.74 (95% CI: 0.67-0.80) for MODS, 0.78 (95% CI: 0.71-0.84) for PIRO, and 0.77 (95% CI: 0.71-0.83) for MEDS. Sensitivity and specificity for APACHE II were 81.5 and 75.3, respectively. CONCLUSIONS: In our study, APACHE II score was found to be the most sensitive and specific in predicting the severity of sepsis compared to other scores.

Xenobiotic Metabolism and Gut Microbiomes.

Humans are exposed to numerous xenobiotics, a majority of which are in the form of pharmaceuticals. Apart from human enzymes, recent studies have indicated the role of the gut bacterial community (microbiome) in metabolizing xenobiotics. However, little is known about the contribution of the plethora of gut microbiome in xenobiotic metabolism. The present study reports the results of analyses on xenobiotic metabolizing enzymes in various human gut microbiomes. A total of 397 available gut metagenomes from individuals of varying age groups from 8 nationalities were analyzed. Based on the diversities and abundances of the xenobiotic metabolizing enzymes, various bacterial taxa were classified into three groups, namely, least versatile, intermediately versatile and highly versatile xenobiotic metabolizers. Most interestingly, specific relationships were observed between the overall drug consumption profile and the abundance and diversity of the xenobiotic metabolizing repertoire in various geographies. The obtained differential abundance patterns of xenobiotic metabolizing enzymes and bacterial genera harboring them, suggest their links to pharmacokinetic variations among individuals. Additional analyses of a few well studied classes of drug modifying enzymes (DMEs) also indicate geographic as well as age specific trends.

Pharmacokinetic Potentiation of Mixed Organophosphate and Pyrethroid Poison Leading to Prolonged Delayed Neuropathy.

Organophosphate (OP) and mixed pesticide poisoning remains an important cause of hospital admission. Therefore, physician must be aware of atypical presentations of delayed neurological complications of poisoning by taking proper patient history. We report a case of a 23-year-old female who presented with high stepping gait and muscle wasting in hands. Patient history revealed consumption of approximately 4ml of mixed pesticide, consisting of 50% chlorpyrifos with synthetic pyrethroid, 5% cypermethrin. The prolonged and severe nature of delayed peripheral neuropathy, persisting at two years of follow-up, suggests that even small quantities of OP taken in combination with a pyrethroid can result in significant morbidity and is irreversible.