Effect of efavirenz-based antiretroviral therapy and high-dose rifampicin on the pharmacokinetics of isoniazid and acetyl-isoniazid.

Objectives: To describe the pharmacokinetics of isoniazid and acetyl-isoniazid in TB/HIV-coinfected patients, and assess the effects of efavirenz co-administration and a 50% increase in the dose of rifampicin on the pharmacokinetic parameters of isoniazid and acetyl-isoniazid. Methods: TB/HIV-coinfected patients participating in the three-treatment-arm RAFA randomized controlled trial conducted in West Africa were recruited into the pharmacokinetics sub-study. Five serial blood samples were collected on a single visit between 4 and 8 weeks after initiation of antituberculosis treatment. Concentration-time data for isoniazid and acetyl-isoniazid were analysed using non-linear mixed-effects models. Results: Isoniazid concentrations from 150 patients were available for analysis, and 79 of these (53%) also had concentrations of acetyl-isoniazid. Isoniazid pharmacokinetics was best described with a two-compartment disposition model with lagged first-order absorption and elimination using a semi-mechanistic model describing hepatic extraction. The model identified two elimination pathways, separating formation of acetyl-isoniazid from other routes of metabolism. The predicted AUC0-24 is reduced by 29% in patients who are fast acetylators of isoniazid and receiving efavirenz-based ART (6.73 versus 4.68 mg·h/L). In slow acetylators, efavirenz-based ART had no effect on isoniazid exposure (AUC0-24 = 17.5 mg·h/L). Conclusions: Efavirenz-based ART affects the acetylation metabolic pathway amongst rapid acetylators, resulting in reduced exposure to isoniazid. Pharmacokinetics of isoniazid and acetyl-isoniazid were not influenced by the 50% increase in rifampicin dose.

Evaluation of initial and steady-state gatifloxacin pharmacokinetics and dose in pulmonary tuberculosis patients by using monte carlo simulations.

A 4-month regimen of gatifloxacin with rifampin, isoniazid, and pyrazinamide is being evaluated for the treatment of tuberculosis in a phase 3 randomized controlled trial (OFLOTUB). A prior single-dose study found that gatifloxacin exposure increased by 14% in the combination. The aims of the study are to evaluate the initial and steady-state pharmacokinetics of gatifloxacin when daily doses are given to patients with newly diagnosed drug-sensitive pulmonary tuberculosis as part of a combination regimen and to evaluate the gatifloxacin dose with respect to the probability of attaining a pharmacokinetic/pharmacodynamic target. We describe the population pharmacokinetics of gatifloxacin from the first dose to a median of 28 days in 169 adults enrolled in the OFLOTUB trial in Benin, Guinea, Senegal, and South Africa. The probability of achieving a ratio of ≥125 for the area under the concentration time curve to infinity (AUC0-∞) for the free fraction of gatifloxacin over the MIC (fAUC/MIC) was investigated using Monte Carlo simulations. The median AUC0-∞ of 41.2 µg · h/ml decreased on average by 14.3% (90% confidence interval [CI], -90.5% to +61.5%) following multiple 400-mg daily doses. At steady state, 90% of patients achieved an fAUC/MIC of ≥125 only when the MIC was <0.125 µg/ml. We conclude that systemic exposure to gatifloxacin declines with repeated daily 400-mg doses when used together with rifampin, isoniazid, and pyrazinamide, thus compensating for any initial increase in gatifloxacin levels due to a drug interaction. (The OFLOTUB study has been registered at ClinicalTrials.gov under registration no. NCT00216385.).

Four-Month High-Dose Rifampicin Regimens for Pulmonary Tuberculosis.

BACKGROUND: Shorter but effective tuberculosis treatment regimens would be of value to the tuberculosis treatment community. High-dose rifampicin has been associated with more rapid and secure lung sterilization and may enable shorter tuberculosis treatment regimens. METHODS: We randomly assigned adults who were given a diagnosis of rifampicin-susceptible pulmonary tuberculosis to a 6-month control regimen, a similar 4-month regimen of rifampicin at 1200 mg/d (study regimen 1 [SR1]), or a 4-month regimen of rifampicin at 1800 mg/d (study regimen 2 [SR2]). Sputum specimens were collected at regular intervals. The primary end point was a composite of treatment failure and relapse in participants who were sputum smear positive at baseline. The noninferiority margin was 8 percentage points. Using a sequence of ordered hypotheses, noninferiority of SR2 was tested first. RESULTS: Between January 2017 and December 2020, 672 patients were enrolled in six countries, including 191 in the control group, 192 in the SR1 group, and 195 in the SR2 group. Noninferiority was not shown. Favorable responses rates were 93, 90, and 87% in the control, SR1, and SR2 groups, respectively, for a country-adjusted absolute risk difference of 6.3 percentage points (90% confidence interval, 1.1 to 11.5) comparing SR2 with the control group. The proportions of participants experiencing a grade 3 or 4 adverse event were 4.0, 4.5, and 4.4% in the control, SR1, and SR2 groups, respectively. CONCLUSIONS: Four-month high-dose rifampicin regimens did not have dose-limiting toxicities or side effects but failed to meet noninferiority criteria compared with the standard 6-month control regimen for treatment of pulmonary tuberculosis. (Funded by the MRC/Wellcome Trust/DFID Joint Global Health Trials Scheme; ClinicalTrials.gov number, NCT02581527.)

Toward Health System Recovery in the Aftermath of Ebola Outbreak in Guinea: New Approaches for Improved Knowledge of Target Populations at the Community Level.

BACKGROUND: Before the COVID-19 pandemic, Guinea has been the epicenter of the huge West Africa Ebola outbreak (2014-2016), that impact heavily the health system. Demographic information is one of the most basic data sources for health systems and services delivery, and yet can be very difficult to obtain with any accuracy. The objectives were to contribute among other to: (i) a determination of the catchment area (health coverage area and responsibility) of the Kirikilan health facility (PCM); (ii) geocoded mapping to find out exactly where these populations per sector of Kirikilan neighborhood lives; (iii) an approach for regular and systematic annual demographic follow up of target populations. METHODS: The study was a 3-year community-based survey with annual follow up of the population within the quartier of Kirikilan in Dubreka Prefecture in Guinea. It was an exhaustive enumeration of the population, sector by sector of the quartier, then there was no sampling size neither estimation. RESULTS: In October 2017 as a baseline of the study, the enumeration showed the total population was 8824 persons, 936 compounds, 1435 households, and the breakdown by sub quartier (sector) has been performed. It's showed the interest of the mapping of the target populations with geo-referenced localization. The annual follow up by demographic enumerus showed a dramatic increase of the size of the population, including strong migration of the evicted population due to urbanization purpose in some districts of Conakry, the capital. CONCLUSION: The study showed the importance of the enumeration and follow up of the target populations, but also of the setting up community data based to improve the district health information system (DHIS 2) in Guinea. The approach has a best practice could be an importunity to improve data sharing, mapping, health quality access, and affordability for a sustainable health toward universal health coverage.

Dying in honour: experiences of end-of-life palliative care during the 2013-2016 Ebola outbreak in Guinea.

With no cure and a high mortality rate, Ebola virus disease (EVD) outbreaks require preparedness for the provision of end-of-life palliative care. This qualitative study is part of a larger project on palliative care in humanitarian contexts. Its goal was to document and deepen understanding of experiences and expectations related to end-of-life palliative care for patients infected with Ebola virus disease (EVD) in West African Ebola treatment centres (ETCs) during the 2013-2016 epidemic. It consisted of 15 in-depth semi-structured interviews with individuals impacted by EVD in a Guinean ETC: either as patients in an ETC, healthcare providers, healthcare providers who were also EVD patients at one point, family relations who visited patients who died in an ETC, or providers of spiritual support to patients and family. Analysis was team based and applied an interpretive descriptive approach. Healthcare delivery in humanitarian emergencies must remain respectful of patient preferences but also local and contextual values and norms. Of key importance in the Guinean context is the culturally valued experience of "dying in honour". This involves accompaniment to facilitate a peaceful death, the possibility of passing on final messages to family members, prayer, and particular practices to enact respect for the bodies of the deceased. Participants emphasized several challenges to such death in Ebola treatment centres (ETCs), as well as practices they deemed helpful to alleviating dying patients' suffering. An overarching message in participants' accounts was that ideally more would have been done for the dying in ETCs. Building on participants' accounts, we outline a number of considerations for optimizing end-of-life palliative care during current and future public health emergencies, including for COVID-19.

Tuberculosis prevalence and associated factors among persons with diabetes mellitus after intensified case finding in three West African countries.

BACKGROUND: To determine the prevalence of tuberculosis (TB) and associated factors in persons with diabetes mellitus (DM) in Benin, Guinea and Senegal. PATIENTS AND METHOD: A cross-sectional study was conducted in the largest DM center in each country. Participants systematically underwent clinical screening and chest radiography. Participants who were symptomatic or with abnormal radiography underwent bacteriological investigations (sputum smear, Xpert MTB/RIF and culture) on sputum. Participants with no TB at enrolment were re-examined for TB six months later. Logistic regression was performed to identify factors associated with TB. RESULTS: There were 5,870 DM patients: 1,881 (32.0%) in Benin, 1,912 (32.6%) in Guinea and 2,077 (35.4%) in Senegal. Out of these, 114 had bacteriologically-confirmed TB, giving a pooled prevalence of 1.9% (95%CI=1.6-2.3). TB prevalence was 0.5% (95%CI=0.3-1.0), 2.4% (95%CI=1.8-3.2) and 2.8% (95%CI=2.2-3.6), respectively, in Benin, Guinea and Senegal. Factors associated with an increased odds of TB diagnosis were a usual residence in Guinea (aOR=2.62;95%CI=1.19-5.77; p=0.016) or in Senegal (aOR=3.73;95%CI=1.85-7.51; p<0.001), the age group of 35-49 years (aOR=2.30;95%CI=1.11-4.79; p=0.025), underweight (aOR=7.34;95%CI=4.65-11.57; p<0.001) and close contact with a TB case (aOR=2.27;95%CI=1.37-3.76; p=0.002). Obesity was associated with lower odds of TB (aOR=0.20; 95%CI=0.06-0.65; p=0.008). CONCLUSION: TB is prevalent among DM patients in Benin, Guinea and Senegal and higher than among the general population. The findings support the need for intensified case finding in DM patients in order to ensure systematic early detection of TB during the routine consultation process.

CD209 genetic polymorphism and tuberculosis disease.

BACKGROUND: Tuberculosis causes significant morbidity and mortality worldwide, especially in sub-Saharan Africa. DC-SIGN, encoded by CD209, is a receptor capable of binding and internalizing Mycobacterium tuberculosis. Previous studies have reported that the CD209 promoter single nucleotide polymorphism (SNP)-336A/G exerts an effect on CD209 expression and is associated with human susceptibility to dengue, HIV-1 and tuberculosis in humans. The present study investigates the role of the CD209 -336A/G variant in susceptibility to tuberculosis in a large sample of individuals from sub-Saharan Africa. METHODS AND FINDINGS: A total of 2,176 individuals enrolled in tuberculosis case-control studies from four sub-Saharan Africa countries were genotyped for the CD209 -336A/G SNP (rs4804803). Significant overall protection against pulmonary tuberculosis was observed with the -336G allele when the study groups were combined (n = 914 controls vs. 1262 cases, Mantel-Haenszel 2 x 2 chi(2) = 7.47, P = 0.006, odds ratio = 0.86, 95%CI 0.77-0.96). In addition, the patients with -336GG were associated with a decreased risk of cavitory tuberculosis, a severe form of tuberculosis disease (n = 557, Pearson's 2x2 chi(2) = 17.34, P = 0.00003, odds ratio = 0.42, 95%CI 0.27-0.65). This direction of association is opposite to a previously observed result in a smaller study of susceptibility to tuberculosis in a South African Coloured population, but entirely in keeping with the previously observed protective effect of the -336G allele. CONCLUSION: This study finds that the CD209 -336G variant allele is associated with significant protection against tuberculosis in individuals from sub-Saharan Africa and, furthermore, cases with -336GG were significantly less likely to develop tuberculosis-induced lung cavitation. Previous in vitro work demonstrated that the promoter variant -336G allele causes down-regulation of CD209 mRNA expression. Our present work suggests that decreased levels of the DC-SIGN receptor may therefore be protective against both clinical tuberculosis in general and cavitory tuberculosis disease in particular. This is consistent with evidence that Mycobacteria can utilize DC-SIGN binding to suppress the protective pro-inflammatory immune response.

Variants in the SP110 gene are associated with genetic susceptibility to tuberculosis in West Africa.

The sst1 locus has been identified in a mouse model to control resistance and susceptibility of Mycobacterium tuberculosis infection. Subsequent studies have now identified Ipr1 (intracellular pathogen resistance 1) to be the gene responsible. Ipr1 is encoded within the sst1 locus and is expressed in the tuberculosis lung lesions and macrophages of sst1-resistant, but not sst1-susceptible mice. We have therefore examined the closest human homologue of Ipr1, SP110, for its ability to control susceptibility to M. tuberculosis infection in humans. In a study of families from The Gambia we have identified three polymorphisms that are associated with disease. On examination of additional families from Guinea-Bissau and the Republic of Guinea, two of these associations were independently replicated. These variants are in strong linkage disequilibrium with each other and lie within a 31-kb block of low haplotypic diversity, suggesting that a polymorphism within this region has a role in genetic susceptibility to tuberculosis in humans.

Vitamin D receptor polymorphisms and susceptibility to tuberculosis in West Africa: a case-control and family study.

Vitamin D receptor (VDR) gene polymorphisms have been implicated in susceptibility to tuberculosis (TB), but reports have been inconsistent. We genotyped the VDR single-nucleotide polymorphisms (SNPs) FokI, BsmI, ApaI, and TaqI in 1139 case patients and control subjects and 382 families from The Gambia, Guinea, and Guinea-Bissau. The transmission-disequilibrium test on family data showed a significant global association of TB with SNP combinations FokI-BsmI-ApaI-TaqI and FokI-ApaI that were driven by the increased transmission to affected offspring of the FokI F and ApaI A alleles in combination. The ApaI A allele was also transmitted to affected offspring significantly more often than expected. Case-control analysis showed no statistically significant association between TB and VDR variants. BsmI, ApaI, and TaqI showed strong linkage disequilibrium. The significance of the family-based associations found between TB and FokI-BsmI-ApaI-TaqI and the FA haplotype supports a role for VDR haplotypes, rather than individual genotypes, in susceptibility to TB.

Variants of the CD40 ligand gene are not associated with increased susceptibility to tuberculosis in West Africa.

Evidence for linkage between tuberculosis and human chromosomal region Xq26 has previously been described. The costimulatory molecule CD40 ligand, encoded by TNFSF5 and located at Xq26.3, is a promising positional candidate. Interactions between CD40 ligand and CD40 are involved in the development of humoral- and cell-mediated immunity, as well as the activation of macrophages, which are the primary host and effector cells for Mycobacterium tuberculosis. We hypothesised that common variation within TNFSF5 might affect susceptibility to tuberculosis disease and, thus, might be responsible for the observed linkage to Xq26. Sequencing 32 chromosomes from a Gambian population identified nine common polymorphisms within the coding, 3' and 5' regulatory sequences of the gene. Six single nucleotide polymorphisms (SNPs) and a 3' microsatellite were genotyped in 121 tuberculosis patients and their available parents. No association with tuberculosis was detected for these variants using a transmission disequilibrium test, although one SNP at -726 showed some evidence of association in males. This finding, however, did not replicate in a separate case control study of over 1,200 West African individuals. We conclude that common genetic variation in TNFSF5 is not likely to affect tuberculosis susceptibility in West Africa and the linkage observed in this region is not due to variation in TNFSF5.