Bedaquiline is a medication recently approved by the FDA for the treatment of multidrug resistant tuberculosis. Due to its recent nature, there exists little information on the efficacy and safety of the drug. A systematic review and meta-analysis was performed to collect what data exist on bedaquiline and assess its efficacy and safety relative to currently recommended regimens, and some specific medications used in those regimens for treating both multidrug resistant and extensively drug-resistant tuberculosis. Nine studies were collected from databases and direct journal searches and pooled to make a sample size of 950 patients receiving a treatment regimen containing bedaquiline. Of these 950 patients on bedaquiline-containing regimens, a high percentage had culture conversion at six months (84.13%, 95% CI = 72.53% - 92.98%), treatment cure (71.86%, 95% CI = 60.94% - 81.60%), and treatment success (70.80%, 95% CI = 61.57% - 79.24%), and a low percentage discontinued bedaquiline (3.65%, 95% CI = 1.98% - 5.81%), or died (6.56%, 95% CI = 4.15% - 9.45%), despite a high number of XDR-TB and HIV co-infected patients. Adverse events due to bedaquiline (21.39%, 95% CI = 11.66% - 33.11%), total severe adverse events (26.50%, 95% CI = 6.98% - 52.86%), hepatotoxicity (14.37%, 95% CI = 2.56 – 33.47%), and QT prolongation percentages (10.37%, 95% CI = 3.19% - 21.01%) were high, but did not lead to bedaquiline discontinuation or death. The efficacy and relative safety of bedaquiline make it a viable option versus current alternative medications and, as part of a regimen, it is far more successful at treating multidrug-, and extensively drug-, resistant tuberculosis than conventional regimens. New treatment regimens only just being put into use, however, such as the Bangladesh regimen, still seem to be superior. More research, including randomized controlled trials, is required to identify how bedaquiline should be incorporated into making multidrug resistant tuberculosis treatment more effective and safe. / 2020-02-20T00:00:00Z

Yes / Objectives: Resistance-associated variants (RAVs) in Rv0678, a regulator of the MmpS5-MmpL5 efflux pump, have been shown to lead to increased MICs of bedaquiline (2- to 8- fold) and clofazimine (2- to 4-fold). The prevalence of these Rv0678 RAVs in clinical isolates and their impact on treatment outcomes are important factors to take into account in bedaquiline treatment guidelines. Methods: Baseline isolates from two bedaquiline MDR-TB clinical trials were sequenced for Rv0678 RAVs and corresponding bedaquiline MICs were determined on 7H11 agar. Rv0678 RAVs were also investigated in non-MDRTB sequences of a population-based cohort. Results: Rv0678 RAVs were identified in 23/347 (6.3%) of MDR-TB baseline isolates. Surprisingly, bedaquiline MICs for these isolates were high (>0.24 mg/L, n¼8), normal (0.03 0.24 mg/L, n¼11) or low(<0.03 mg/L, n¼4). A variant at position 11 in the intergenic region mmpS5–Rv0678 was identified in 39 isolates (11.3%) and appeared to increase the susceptibility to bedaquiline. In non-MDR-TB isolates, the frequency of Rv0678 RAVs was lower (6/ 852 or 0.7%). Competition experiments suggested that rifampicin was not the drug selecting for Rv0678 RAVs. Conclusions: RAVs in Rv0678 occur more frequently in MDR-TB patients than previously anticipated, are not associated with prior use of bedaquiline or clofazimine, and in the majority of cases do not lead to bedaquiline MICs above the provisional breakpoint (0.24mg/L). Their origin remains unknown. Given the variety of RAVs in Rv0678 and their variable effects on the MIC, only phenotypic drug-susceptibility methods can currently be used to assess bedaquiline susceptibility. / This work was supported by Janssen Pharmaceutica. N. C. was supported by a Baekeland PhD scholarship from the Flemish Institute for Scientific Technology (IWT 130308, Belgium). C. J. M., L. R. and B. d. J. were supported by a European Research Council Starting Grant INTERRUPTB (311725).

no / The role of mutations in genes associated with phenotypic resistance to bedaquiline (BDQ) and delamanid (DLM) in Mycobacterium tuberculosis complex (MTBc) strains is poorly characterized. A clear understanding of the genetic variants' role is crucial to guide the development of molecular-based drug susceptibility testing (DST). In this work, we analyzed all mutations in candidate genomic regions associated with BDQ- and DLM-resistant phenotypes using a whole-genome sequencing (WGS) data set from a collection of 4,795 MTBc clinical isolates from six countries with a high burden of tuberculosis (TB). From WGS analysis, we identified 61 and 163 unique mutations in genomic regions potentially involved in BDQ- and DLM-resistant phenotypes, respectively. Importantly, all strains were isolated from patients who likely have never been exposed to these medicines. To characterize the role of mutations, we calculated the free energy variation upon mutations in the available protein structures of Ddn (DLM), Fgd1 (DLM), and Rv0678 (BDQ) and performed MIC assays on a subset of MTBc strains carrying mutations to assess their phenotypic effect. The combination of structural and phenotypic data allowed for cataloguing the mutations clearly associated with resistance to BDQ (n = 4) and DLM (n = 35), only two of which were previously described, as well as about a hundred genetic variants without any correlation with resistance. Significantly, these results show that both BDQ and DLM resistance-related mutations are diverse and distributed across the entire region of each gene target, which is of critical importance for the development of comprehensive molecular diagnostic tools.

<p>  </p> <p>A multidisciplinary study that evaluated Quality Control (QC) laboratory (lab) accreditation, and a salt screen for bedaquiline. Medicines testing facilities always seek to ensure the accuracy of data from their QC labs by attaining accreditation. This research proposed that an understanding of the cross-linkages in the requirements for implementing the 2 most widely used lab standards will facilitate testing efficiencies, and reduce the risks of accreditation failures. For the salt project, the study proposed that new salts of bedaquiline will be formed from acid-base reactions following the pKa rule. Characterizing the salts will provide specifications for the new molecular entities, and form a selection-criteria for a lead candidate.</p> <p>The research reviewed 2 lab standards: the ISO/IEC17025:2017 and the WHO Good Practices for Pharmaceutical QC labs, and identified the areas of overlap in their requirements. It then developed and tested affordable models that mitigate the 3 identified areas of high risks to lab accreditation. Additionally, it mixed<em> equimolar amounts of bedaquiline base with select counterions that have ≥ 2 pKa units in organic solvents, to yield salts</em>. ICHQ6 guidance was used to characterize the new salts.</p> <p>The highest risks to laboratory accreditation were linked to 3 quality system metrics, namely: ‘Proficiency Testing’, ‘Validation’, and ‘Measurement Traceability’. Using the identified areas of overlap in the 2 laboratory standards, this research provided tutorial videos, a competency matrix, and some instrument validation data, to optimize the requirements for lab accreditation. For the salt screen, five new candidates were synthesized as alternatives to the existing fumarate salt of bedaquiline. The results of their physicochemical properties were used for selecting a lead moiety.</p> <p>The research provided evidence that the multipronged models developed will improve efficiencies in QC labs, and increase their chances of attaining international accreditations. It also discovered the best modes for synthesizing the new salts of bedaquiline, and provided critical data to help Pharma make an informed choice for a lead candidate.</p>

Tuberculosis (TB) is the world’s most deadly infectious disease and causes enormous public health problems. The comorbidity with HIV and the rise of multidrug-resistant TB strains impede successful therapy through drug-drug interactions and the lack of efficient second-line treatments. The aim of this thesis was to support the improvement of anti-TB therapy through development of pharmacometric models, specifically focusing on the novel drug bedaquiline, pharmacokinetic interactions and methods for pooled population analyses. A population pharmacokinetic model of bedaquiline and its metabolite M2, linked to semi-mechanistic models of body weight and albumin concentrations, was developed and used for exposure-response analysis. Treatment response was quantified by measurements of mycobacterial load and early bedaquiline exposure was found to significantly impact the half-life of bacterial clearance. The analysis represents the first successful characterization of a concentration-effect relationship for bedaquiline. Single-dose Phase I studies investigating potential interactions between bedaquiline and efavirenz, nevirapine, ritonavir-boosted lopinavir, rifampicin and rifapentine were analyzed with a model-based approach. Substantial effects were detected in several cases and dose-adjustments mitigating the impact were suggested after simulations. The interaction effects of nevirapine and ritonavir-boosted lopinavir were also confirmed in patients with multidrug-resistant TB on long-term treatment combining the antiretrovirals and bedaquiline. Furthermore, the outcomes from model-based analysis were compared to results from conventional non-compartmental analysis in a simulation study. Non-compartmental analysis was found to consistently underpredict the interaction effect when most of the concentration-time profile was not observed, as commonly is the case for compounds with very long terminal half-life such as bedaquiline. To facilitate pooled analyses of individual patient data from multiple sources a structured development procedure was outlined and a fast diagnostic tool for extensions of the stochastic model components was developed. Pooled analyses of nevirapine and rifabutin pharmacokinetics were performed; the latter generating comprehensive dosing recommendations for combined administration of rifabutin and antiretroviral protease inhibitors. The work presented in this thesis demonstrates the usefulness of pharmacometric techniques to improve treatment of TB and especially contributes evidence to inform optimized dosing regimens of new and old anti-TB drugs in various clinical contexts.

Tuberculosis, caused by Mycobacterium tuberculosis, still poses a huge global health threat today. During infection, the bacilli are believed to confront with various stresses, including hypoxia. Hypoxia is known to trigger the bacteria to adapt into a nonreplicating dormant state associated with reduced drug susceptibility. In addition to dormancy, mycobacteria, like other bacteria, may switch to sessile biofilm growth that is generally associated with augmented drug and stress tolerance. Bacterial biofilm is physically heterogeneous and may harbor cells displaying distinct metabolic activities. It is therefore likely that some cell populations within an established biofilm are in a nonreplicating dormant state. A better understanding of mycobacterial dormancy establishment and biofilm growth could unveil crucial bacillary survival strategies that will provide insights into a rational design of chemotherapy regimen.The mycobacterial chaperonin 60.1 (Cpn60.1, also known as GroEL1), a probable chaperonin and/or nucleoid associated protein, is necessary for mycobacterial cell wall virulence lipid biosynthesis, which was reported to be enhanced at the early stage of mycobacterial hypoxic adaptation, and for reduced drug susceptibility under aerobic condition. We therefore investigated whether Cpn60.1 was essential for mycobacterial adaptation to hypoxic dormancy using Mycobacterium bovis BCG as the model organism. We found that Cpn60.1, although nonessential for mycobacterial survival, reduced isoniazid (INH) susceptibility under hypoxia. Unexpectedly and interestingly, INH’s bactericidal activity was found to involve electron transport chain perturbation (e.g. enhanced oxygen consumption and increased adenosine triphosphate level) via NADH dehydrogenases, succinate dehydrogenases, cytochrome bc1 and F0F1 ATP synthase. Moreover, respiratory reprogramming to cytochrome bd was observed to protect against INH-induced killing.Intriguingly, we found that Cpn60.1 was required for respiratory and energetic downregulation under excess glycerol as well as in response to drugs (such as Q203 inhibiting cytochrome bc1). Cpn60.1 also played a role in lipidomic adaptation under excess glycerol (e.g. enhanced phthiocerol dimycocerosate and glycerol-based lipids synthesis but repressed trehalose-based lipids synthesis). Defective energetic downregulation in the absence of Cpn60.1 compromised the establishment of the Crabtree effect characterized by respiratory downregulation, glycolytic enhancement and secretion of several metabolites (i.e. pyruvate, succinate, acetate and glutamate). The Crabtree effect was necessary for mycobacterial adaptation to excess glycerol and biofilm growth. Due to a compromised Crabtree effect, a Cpn60.1-deficient Mycobacterium bovis BCG strain, i.e. the Δcpn60.1 strain, suffered from methylglyoxal-induced growth stasis under excess glycerol, leading to the biofilm defect under the standard biofilm medium. Given the essentiality for Cpn60.1 in mycobacterial respiratory adaptation under stresses, it is likely that the enhanced INH susceptibility of the Δcpn60.1 strain under hypoxia was due to a problematic respiratory reprogramming.In summary, Mycobacterium bovis BCG Cpn60.1 is not required for bacillary survival under hypoxic dormancy. However, it participates in various adaptations (e.g. respiratory downregulation) necessary for mycobacterial biofilm growth and for escaping INH’s bactericidal mechanism. / Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie) / info:eu-repo/semantics/nonPublished