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RationaleStandardized weight-based dose of anti-tubercular drugs contributes to a substantial incidence of toxicities, inadequate treatment response, and relapse, in part due to variable drug levels achieved. Single nucleotide polymorphisms (SNPs) in the N-acetyltransferase-2 (NAT2) gene explain the majority of interindividual pharmacokinetic variability of isoniazid (INH). However, an obstacle to implementing pharmacogenomic-guided dosing is the lack of a point-of-care assay.ObjectivesTo develop and test a NAT2 classification algorithm, validate its performance in predicting isoniazid clearance, and develop a prototype pharmacogenomic assay.MethodsWe trained random forest models to predict NAT2 acetylation genotype from unphased SNP data using a global collection of 8,561 phased genomes. We enrolled 48 pulmonary TB patients, performed sparse pharmacokinetic sampling, and tested the acetylator prediction algorithm accuracy against estimated INH clearance. We then developed a cartridge-based multiplex qPCR assay on the GeneXpert platform and assessed its analytical sensitivity on whole blood samples from healthy individuals.Measurements and Main ResultsWith a 5-SNP model trained on two-thirds of the data (n=5,738), out-of-sample acetylation genotype prediction accuracy on the remaining third (n=2,823) was 100%. Among the 48 TB patients, predicted acetylator types were: 27 (56.2%) slow, 16 (33.3%) intermediate and 5 (10.4%) rapid. INH clearance rates were lowest in predicted slow acetylators (median 19.3 L/hr), moderate in intermediate acetylators (median 41.0 L/hr) and highest in fast acetylators (median 46.7 L/hr). The cartridge-based assay accurately detected all allele patterns directly from 25ul of whole blood.ConclusionsAn automated pharmacogenomic assay on a platform widely used globally for tuberculosis diagnosis could enable personalized dosing of isoniazid.SummaryThis manuscript describes the development and validation of point-of-care multiplex pharmacogenomic assay to guide personalized dosing of isoniazid for treatment or prevention of tuberculosis.

Tuberculosis (TB) kills more people than any other infectious disease. Challenges for developing better treatments include the complex pathology due to within-host immune dynamics, interpatient variability in disease severity and drug pharmacokinetics-pharmacodynamics (PK-PD), and the growing emergence of resistance. Model-informed drug development using quantitative and translational pharmacology has become increasingly recognized as a method capable of drug prioritization and regimen optimization to efficiently progress compounds through TB drug development phases. In this review, we examine translational models and tools, including plasma PK scaling, site-of-disease lesion PK, host-immune and bacteria interplay, combination PK-PD models of multidrug regimens, resistance formation, and integration of data across nonclinical and clinical phases.We propose a workflow that integrates these tools with computational platforms to identify drug combinations that have the potential to accelerate sterilization, reduce relapse rates, and limit the emergence of resistance.

Background Rifapentine exposure is associated with bactericidal activity against Mycobacterium tuberculosis, but high interindividual variation in plasma concentrations is encountered. Objectives To investigate a genomic association with interindividual variation of rifapentine exposure, SNPs of six human genes involving rifamycin metabolism (AADAC, CES2), drug transport (SLCO1B1, SLCO1B3) and gene regulation (HNF4A, PXR) were evaluated. Methods We characterized these genes in 173 adult participants in treatment trials of the Tuberculosis Trials Consortium. Participants were stratified by self-identified race (black or non-black), and rifapentine AUC from 0 to 24 h (AUC0–24) was adjusted by analysis of covariance for SNPs, rifapentine dose, sex, food and HIV coinfection. This study was registered at ClinicalTrials.gov under identifier NCT01043575. Results The effect on rifapentine least squares mean AUC0–24 in black participants overall decreased by –10.2% for AADAC rs1803155 G versus A allele (Wald test: P = 0.03; false discovery rate, 0.10). Black participants with one G allele in AADAC rs1803155 were three times as likely to have below target bactericidal rifapentine exposure than black participants with the A allele (OR, 2.97; 95% CI: 1.16, 7.58). With two G alleles, the OR was greater. In non-black participants, AADAC rs1803155 SNP was not associated with rifapentine exposure. In both black and non-black participants, other evaluated genes were not associated with rifapentine exposure (P > 0.05; false discovery rate > 0.10). Conclusions Rifapentine exposure in black participants varied with AADAC rs1803155 genotype and the G allele was more likely to be associated with below bactericidal target rifapentine exposure. Further pharmacogenomic study is needed to characterize the association of the AADAC rs1803155 with inadequate rifapentine exposure in different patient groups.

BACKGROUND: Successful hematopoietic stem cell transplantation (HSCT) requires a rapid and durable hematopoietic recovery.AIM: The aim of our study was to analyse factors that influence hematopoietic recovery after autologous HSCT.MATERIALS AND METHODS: Multiple regression analysis was used to analyse factors affecting neutrophil and platelet engraftment in 90 autologous transplanted patients – 30 with acute myeloid leukaemia (AML), 30 with lymphoma and 30 with multiple myeloma (MM) from 2008 till 2016.RESULTS: The neutrophil recovery in AML patients was significantly influenced by transfusion support with random-donor platelets, sex and number of transplanted mononuclear cells (MNC) and CD34+ cells; and in lymphoma patients, it was influenced by sex, age, mobilisation strategy and some transplanted MNC. The influence of investigated factors on neutrophil engraftment in MM patients was not statistically significant. The platelet recovery in AML patients was influenced by transfusion support with random-donor platelets; in lymphoma patients, it was influenced by sex, age, time from diagnosis to harvesting and time from diagnosis to HSCT; and in MM patients it was influenced by transfusion support with random-donor platelets.CONCLUSION: Additional studies are necessary to better understanding of engraftment kinetic to improve the safety of HSCT and to minimise potential complications and expenses related to HSCT.

Tuberculosis (TB) drug, regimen, and vaccine development rely heavily on preclinical animal experiments, and quantification of bacterial and immune response dynamics is essential for understanding drug and vaccine efficacy. A mechanism-based model was built to describe Mycobacterium tuberculosis H37Rv infection over time in BALB/c and athymic nude mice, which consisted of bacterial replication, bacterial death, and adaptive immune effects., Tuberculosis (TB) drug, regimen, and vaccine development rely heavily on preclinical animal experiments, and quantification of bacterial and immune response dynamics is essential for understanding drug and vaccine efficacy. A mechanism-based model was built to describe Mycobacterium tuberculosis H37Rv infection over time in BALB/c and athymic nude mice, which consisted of bacterial replication, bacterial death, and adaptive immune effects. The adaptive immune effect was best described by a sigmoidal function on both bacterial load and incubation time. Applications to demonstrate the utility of this baseline model showed (i) the important influence of the adaptive immune response on pyrazinamide (PZA) drug efficacy, (ii) a persistent adaptive immune effect in mice relapsing after chemotherapy cessation, and (iii) the protective effect of vaccines after M. tuberculosis challenge. These findings demonstrate the utility of our model for describing M. tuberculosis infection and corresponding adaptive immune dynamics for evaluating the efficacy of TB drugs, regimens, and vaccines.

Diffuse optical tomography (DOT) is an emerging imaging technique which uses light for diagnostic purposes in a non-invasive and non-ionizing way. In this paper, we focus on DOT application to female breast screening, where the surface of the breast is illuminated by light sources and the outgoing light is collected on the surface. The comparison of measured light data with the equivalent field obtained from a relevant mathematical model yields the DOT inverse problem whose solution provides an estimate of the optical coefficients of the tissue. These latter, in turn, can be related to clinical markers for cancer detection. The goal of this work is to propose a mathematical and computational approach tailored to the concept of a DOT imaging device able to perform fast and accurate screenings at an affordable cost. Namely, we address two original points about the crucial issue of the solution of the severely ill-conditioned DOT inverse problem: (a) a computational approach based on Green's functions which do not require the exact knowledge of the tissue geometry, proposed here in the declination of the Method of Fundamental Solutions, which allows to enforce correct boundary conditions; (b) the elastic net regularization technique that shares the desirable properties of both the l2 - and l1 -norm penalization approaches and opens the possibility for sparsity recognition in the optical coefficients field and refinement procedures.

SUMMARY POINTS: (*) Adherence to prescribed treatment remains a critical component of clinical trials in tuberculosis (TB) treatment. Recent evidence indicates that adherence strongly influences the outcome of therapy; attention to its quantification and measures to assure its implementation should increase. (*) In the context of a World Health Organization (WHO) Technical Consultation on “Advances in Clinical Trial Design for Development of New TB Treatments,” we reviewed the challenges related to adherence confronting the trials community. (*) We discuss the importance of adherence to therapy in TB clinical trials, consider several definitions and measures of adherence, comment on the standard provided by directly observed therapy (DOT), and briefly review evolving electronic methods for the assessment of adherence. (*) Adherence affects both the outcome of therapy and the risk of acquired drug resistance. Assessment of adherence should consider not only overall adherence but also the timing and intensity of nonadherence. (*) Appropriate methods for pooling and analyzing electronic data on adherence are needed. (*) Better methods are needed for linking information on adherence to individual pharmacokinetics and pharmacodynamics and to individual patient outcomes.

In preclinical studies, selenite had single agent activity and radiosensitized tumors in vivo. Here we report results from a Phase 1 trial in 15 patients with metastatic cancer treated with selenite (5.5 to 49.5 mg) orally as a single dose 2 hours before each radiation therapy (RT) treatment. Patients received RT regimens that were standard of care. The primary objective of the study was to assess the safety of this combination therapy. Secondary objectives included measurement of pharmacokinetics (PK) and evaluation of efficacy. Endpoints included assessment of PK, toxicity, tumor response, and pain before and after treatment. The half-life of selenite was 18.5 hours. There were no adverse events attributable to selenite until the 33 mg dose level, at which the primary toxicities were grade 1 GI side effects. One patient treated with 49.5 mg had grade 2 GI toxicity. Although this was not a DLT, it was felt that the highest acceptable dose in this patient population was 33 mg. Most patients had stabilization of disease within the RT fields, with some demonstrating objective evidence of tumor regression. Most patients had a marked improvement in pain and seven out of nine patients with prostate cancer had a decrease in PSA ranging from 11-78%. Doses up to 33 mg selenite were well tolerated in combination with RT. A randomized, well controlled study is needed at the 33 mg dose level to determine if selenite results in clinically meaningful improvements in the response to palliative RT.

Background Linezolid (LZD) is bactericidal against Mycobacterium tuberculosis, but it has treatment-limiting toxicities. A better understanding of exposure-response relationships governing LZD efficacy and toxicity will inform dosing strategies. Because in vitro monotherapy studies yielded conflicting results, we explored LZD pharmacokinetic/pharmacodynamic (PK/PD) relationships in vivo against actively and nonactively multiplying bacteria, including in combination with pretomanid. Methods Linezolid multidose pharmacokinetics were modeled in mice. Dose-fractionation studies were performed in acute (net bacterial growth) and chronic (no net growth) infection models. In acute models, LZD was administered alone or with bacteriostatic or bactericidal pretomanid doses. Correlations between PK/PD parameters and lung colony-forming units (CFUs) and complete blood counts were assessed. Results Overall, time above minimum inhibitory concentration (T>MIC) correlated best with CFU decline. However, in growth-constrained models (ie, chronic infection, coadministration with pretomanid 50 mg/kg per day), area under the concentration-time curve over MIC (AUC/MIC) had similar explanatory power. Red blood cell counts correlated strongly with LZD minimum concentration (Cmin). Conclusions Although T>MIC was the most consistent correlate of efficacy, AUC/MIC was equally predictive when bacterial multiplication was constrained by host immunity or pretomanid. In effective combination regimens, administering the same total LZD dose less frequently may be equally effective and cause less Cmin-dependent toxicity., Linezolid is an efficacious TB drug that exhibits dose- and duration-dependent toxicity. Using animal models, we show that decreasing dosing frequency while maintaining the same total weekly dose may be a viable strategy to maintain efficacy while decreasing toxicity.

Background Linezolid is increasingly important for multidrug-resistant tuberculosis (MDR-TB) treatment. However, among children with MDR-TB, there are no linezolid pharmacokinetic data, and its adverse effects have not yet been prospectively described. We characterised the pharmacokinetics, safety, and optimal dose of linezolid in children treated for MDR-TB. Methods and findings Children routinely treated for MDR-TB in 2 observational studies (2011–2015, 2016–2018) conducted at a single site in Cape Town, South Africa, underwent intensive pharmacokinetic sampling after either a single dose or multiple doses of linezolid (at steady state). Linezolid pharmacokinetic parameters, and their relationships with covariates of interest, were described using nonlinear mixed-effects modelling. Children receiving long-term linezolid as a component of their routine treatment had regular clinical and laboratory monitoring. Adverse events were assessed for severity and attribution to linezolid. The final population pharmacokinetic model was used to derive optimal weight-banded doses resulting in exposures in children approximating those in adults receiving once-daily linezolid 600 mg. Forty-eight children were included (mean age 5.9 years; range 0.6 to 15.3); 31 received a single dose of linezolid, and 17 received multiple doses. The final pharmacokinetic model consisted of a one-compartment model characterised by clearance (CL) and volume (V) parameters that included allometric scaling to account for weight; no other evaluated covariates contributed to the model. Linezolid exposures in this population were higher compared to exposures in adults who had received a 600 mg once-daily dose. Consequently simulated, weight-banded once-daily optimal doses for children were lower than those currently used for most weight bands. Ten of 17 children who were followed long term had a linezolid-related adverse event, including 5 with a grade 3 or 4 event, all anaemia. Adverse events resulted in linezolid dose reductions in 4, temporary interruptions in 5, and permanent discontinuation in 4 children. Limitations of the study include the lack of very young children (none below 6 months of age), the limited number who were HIV infected, and the modest number of children contributing to long-term safety data. Conclusions Linezolid-related adverse effects were frequent and occasionally severe. Careful linezolid safety monitoring is required. Compared to doses currently used in children in many settings for MDR-TB treatment, lower doses may approximate current adult target exposures, might result in fewer adverse events, and should therefore be evaluated., Using data from two cohorts, Anthony Garcia-Prats and colleagues model the appropriate dosing necessary to achieve target concentrations for linezolid to treat children with multidrug-resistant tuberculosis., Author summary Why was this study done? Linezolid is an antibiotic that has recently been repurposed for the treatment of multidrug-resistant tuberculosis (MDR-TB). Based on emerging data from clinical trials, it is now recommended for inclusion as a priority in treatment regimens for adults and children. There is a lack of evidence-based dosing guidelines for linezolid in children for MDR-TB. Linezolid has frequent adverse effects that are associated with higher doses and longer durations of treatment, but this has not been well described in children treated for MDR-TB. What did the researchers do and find? We assessed linezolid pharmacokinetics (concentrations) and safety among children routinely treated for MDR-TB from 2 observational studies. We modelled this pharmacokinetic data and simulated the doses in children that would be needed to achieve current targets. Doses supported by our data for some weight bands were lower than currently in use, which may reduce the risk of adverse effects. Linezolid-related adverse effects were frequent—with low haemoglobin being the most common—and occasionally severe (grade 3 or 4). What do these findings mean? Revised linezolid doses supported by this study now provide an evidence base for international dosing recommendations. All linezolid-treated children with MDR-TB should have careful safety monitoring to include at least regular haemoglobin monitoring. Larger studies, evaluating the revised dosing, are needed to better characterise linezolid safety and to assess the risk of more rare linezolid-related events, especially given the small number of children in this study.

We study the one-dimensional nonlinear Schrodinger equation with the cubic–quintic combination of attractive and repulsive nonlinearities, and a trapping potential represented by a delta-function. We determine all bound states with a positive soliton profile through explicit formulas and, using bifurcation theory, we describe their behavior with respect to the propagation constant. This information is used to prove their stability by means of the rigorous theory of orbital stability of Hamiltonian systems. The presence of the trapping potential gives rise to a regime where two stable bound states coexist, with different powers and same propagation constant.

The End TB Strategy, proposed by the World Health Organization (WHO) in 2014, calls for a 90% reduction in tuberculosis (TB)-related deaths and an 80% reduction in the TB incidence by 2030 [1]. TB remains a leading cause of death in children under five years of age [2], and interventions to eliminate preventable child deaths from TB are urgently needed. Additional and effective TB prevention measures are crucial for the End TB Strategy goals to be met [3]. Footnotes This manuscript has recently been accepted for publication in the European Respiratory Journal . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article. Conflict of interest: Dr. Radtke has nothing to disclose. Conflict of interest: Dr. Hibma reports I am an employee of Pfizer Inc. Conflict of interest: Dr. Hesseling has nothing to disclose. Conflict of interest: Dr. Savic has nothing to disclose.

Dihydroartemisinin-piperaquine (DHA-PQ) is under study for intermittent preventive treatment during pregnancy (IPTp), but it may accelerate selection for drug resistance. Understanding the relationships between piperaquine concentration, prevention of parasitemia, and selection for decreased drug sensitivity can inform control policies and optimization of DHA-PQ dosing. Piperaquine concentrations, measures of parasitemia, and Plasmodium falciparum genotypes associated with decreased aminoquinoline sensitivity in Africa (pfmdr1 86Y, pfcrt 76T) were obtained from pregnant Ugandan women randomized to IPTp with sulfadoxine-pyrimethamine (SP) or DHA-PQ. Joint pharmacokinetic/pharmacodynamic models described relationships between piperaquine concentration and the probability of genotypes of interest using nonlinear mixed effects modeling. An increase in the piperaquine plasma concentration was associated with a log-linear decrease in risk of parasitemia. Our models predicted that higher median piperaquine concentrations would be required to provide 99% protection against mutant infections than against wild-type infections (pfmdr1: N86, 9.6 ng/ml; 86Y, 19.6 ng/ml; pfcrt: K76, 6.5 ng/ml; 76T, 19.6 ng/ml). Comparing monthly, weekly, and daily dosing, daily low-dose DHA-PQ was predicted to result in the fewest infections and the fewest mutant infections per 1,000 pregnancies (predicted mutant infections for pfmdr1 86Y: SP monthly, 607; DHA-PQ monthly, 198; DHA-PQ daily, 1; for pfcrt 76T: SP monthly, 1,564; DHA-PQ monthly, 283; DHA-PQ daily, 1). Our models predict that higher piperaquine concentrations are needed to prevent infections with the pfmdr1/pfcrt mutant compared to those with wild-type parasites and that, despite selection for mutants by DHA-PQ, the overall burden of mutant infections is lower for IPTp with DHA-PQ than for IPTp with SP. (This study has been registered at ClinicalTrials.gov under identifier {"type":"clinical-trial","attrs":{"text":"NCT02282293","term_id":"NCT02282293"}}NCT02282293.)

Tuberculosis kills more people than any other infectious disease. Three pivotal trials testing 4-month regimens failed to meet non-inferiority margins; however, approximately four-fifths of participants were cured. Through a pooled analysis of patient-level data with external validation, we identify populations eligible for 4-month treatment, define phenotypes that are hard to treat and evaluate the impact of adherence and dosing strategy on outcomes. In 3,405 participants included in analyses, baseline smear grade of 3+ relative to2+, HIV seropositivity and adherence of ≤90% were significant risk factors for unfavorable outcome. Four-month regimens were non-inferior in participants with minimal disease defined by2+ sputum smear grade or non-cavitary disease. A hard-to-treat phenotype, defined by high smear grades and cavitation, may require durations6 months to cure all. Regimen duration can be selected in order to improve outcomes, providing a stratified medicine approach as an alternative to the 'one-size-fits-all' treatment currently used worldwide.

We consider the Kronrod extension of generalizations of the Micchelli-Rivlin quadrature formula for the Fourier-Chebyshev coefficients with the highest algebraic degree of precision. For analytic functions, the remainder term of these quadrature formulas can be represented as a contour integral with a complex kernel. We study the kernel on elliptic contours with foci at the points ∓1 and the sum of semi-axes ρ>1 for the mentioned quadrature formulas. We derive L∞-error bounds and L1-error bounds for these quadrature formulas. Finally, we obtain explicit bounds by expanding the remainder term. Numerical examples that compare these error bounds are included.

Understanding the distribution patterns of antibiotics at the site of infection is paramount to selecting adequate drug regimens and developing new antibiotics. Tuberculosis (TB) lung lesions are made of various immune cell types, some of which harbor persistent forms of the pathogen, Mycobacterium tuberculosis. By combining high resolution MALDI MSI with histology staining and quantitative image analysis in rabbits with active TB, we have mapped the distribution of a fluoroquinolone at high resolution, and identified the immune-pathological factors driving its heterogeneous penetration within TB lesions, in relation to where bacteria reside. We find that macrophage content, distance from lesion border and extent of necrosis drive the uneven fluoroquinolone penetration. Preferential uptake in macrophages and foamy macrophages, where persistent bacilli reside, compared to other immune cells present in TB granulomas, was recapitulated in vitro using primary human cells. A nonlinear modeling approach was developed to help predict the observed drug behavior in TB lesions. This work constitutes a methodological advance for the co-localization of drugs and infectious agents at high spatial resolution in diseased tissues, which can be applied to other diseases with complex immunopathology.

BackgroundDihydroartemisinin-piperaquine (DHA-PQ) is highly efficacious as intermittent preventive therapy for malaria during pregnancy (IPTp). Determining associations between piperaquine (PQ) exposure, malaria risk, and adverse birth outcomes informs optimal dosing strategies.MethodsHuman immunodeficiency virus-uninfected pregnant women (n = 300) were enrolled in a placebo-controlled trial of IPTp at 12-20 weeks' gestation and randomized to sulfadoxine-pyrimethamine every 8 weeks, DHA-PQ every 8 weeks, or DHA-PQ every 4 weeks during pregnancy. Pharmacokinetic sampling for PQ was performed every 4 weeks, and an intensive pharmacokinetic substudy was performed in 30 women at 28 weeks' gestation. Concentration-effect relationships were assessed between exposure to PQ; the prevalence of Plasmodium falciparum infection during pregnancy; outcomes at delivery including placental malaria, low birth weight, and preterm birth; and risks for toxicity. Simulations of new dosing scenarios were performed.ResultsModel-defined PQ target venous plasma concentrations of 13.9 ng/mL provided 99% protection from P. falciparum infection during pregnancy. Each 10-day increase in time above target PQ concentrations was associated with reduced odds of placental parasitemia, preterm birth, and low birth weight, though increases in PQ concentrations were associated with QT interval prolongation. Modeling suggests that daily or weekly administration of lower dosages of PQ, compared to standard dosing, will maintain PQ trough levels above target concentrations with reduced PQ peak levels, potentially limiting toxicity.ConclusionsThe protective efficacy of IPTp with DHA-PQ was strongly associated with higher drug exposure. Studies of the efficacy and safety of alternative DHA-PQ IPTp dosing strategies are warranted.Clinical trials registrationNCT02163447.