Browsing by Subject "Bedaquiline"

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    Open Access
    A landscape of genomic alterations at the root of a near-untreatable tuberculosis epidemic
    (2020-02-21) Klopper, Marisa; Heupink, Tim H; Hill-Cawthorne, Grant; Streicher, Elizabeth M; Dippenaar, Anzaan; de Vos, Margaretha; Abdallah, Abdallah M; Limberis, Jason; Merker, Matthias; Burns, Scott; Niemann, Stefan; Dheda, Keertan; Posey, James; Pain, Arnab; Warren, Robin M
    Abstract Background Atypical Beijing genotype Mycobacterium tuberculosis strains are widespread in South Africa and have acquired resistance to up to 13 drugs on multiple occasions. It is puzzling that these strains have retained fitness and transmissibility despite the potential fitness cost associated with drug resistance mutations. Methods We conducted Illumina sequencing of 211 Beijing genotype M. tuberculosis isolates to facilitate the detection of genomic features that may promote acquisition of drug resistance and restore fitness in highly resistant atypical Beijing forms. Phylogenetic and comparative genomic analysis was done to determine changes that are unique to the resistant strains that also transmit well. Minimum inhibitory concentration (MIC) determination for streptomycin and bedaquiline was done for a limited number of isolates to demonstrate a difference in MIC between isolates with and without certain variants. Results Phylogenetic analysis confirmed that two clades of atypical Beijing strains have independently developed resistance to virtually all the potent drugs included in standard (pre-bedaquiline) drug-resistant TB treatment regimens. We show that undetected drug resistance in a progenitor strain was likely instrumental in this resistance acquisition. In this cohort, ethionamide (ethA A381P) resistance would be missed in first-line drug-susceptible isolates, and streptomycin (gidB L79S) resistance may be missed due to an MIC close to the critical concentration. Subsequent inadequate treatment historically led to amplification of resistance and facilitated spread of the strains. Bedaquiline resistance was found in a small number of isolates, despite lack of exposure to the drug. The highly resistant clades also carry inhA promoter mutations, which arose after ethA and katG mutations. In these isolates, inhA promoter mutations do not alter drug resistance, suggesting a possible alternative role. Conclusion The presence of the ethA mutation in otherwise susceptible isolates from ethionamide-naïve patients demonstrates that known exposure is not an adequate indicator of drug susceptibility. Similarly, it is demonstrated that bedaquiline resistance can occur without exposure to the drug. Inappropriate treatment regimens, due to missed resistance, leads to amplification of resistance, and transmission. We put these results into the context of current WHO treatment regimens, underscoring the risks of treatment without knowledge of the full drug resistance profile.
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    Open Access
    A landscape of genomic alterations at the root of a near-untreatable tuberculosis epidemic
    (2020-02-04) Klopper, Marisa; Heupink, Tim H; Hill-Cawthorne, Grant; Streicher, Elizabeth M; Dippenaar, Anzaan; de Vos, Margaretha; Abdallah, Abdallah M; Limberis, Jason; Merker, Matthias; Burns, Scott; Niemann, Stefan; Dheda, Keertan; Posey, James; Pain, Arnab; Warren, Robin M
    Abstract Background Atypical Beijing genotype Mycobacterium tuberculosis strains are widespread in South Africa and have acquired resistance to up to 13 drugs on multiple occasions. It is puzzling that these strains have retained fitness and transmissibility despite the potential fitness cost associated with drug resistance mutations. Methods We conducted Illumina sequencing of 211 Beijing genotype M. tuberculosis isolates to facilitate the detection of genomic features that may promote acquisition of drug resistance and restore fitness in highly resistant atypical Beijing forms. Phylogenetic and comparative genomic analysis was done to determine changes that are unique to the resistant strains that also transmit well. Minimum inhibitory concentration (MIC) determination for streptomycin and bedaquiline was done for a limited number of isolates to demonstrate a difference in MIC between isolates with and without certain variants. Results Phylogenetic analysis confirmed that two clades of atypical Beijing strains have independently developed resistance to virtually all the potent drugs included in standard (pre-bedaquiline) drug-resistant TB treatment regimens. We show that undetected drug resistance in a progenitor strain was likely instrumental in this resistance acquisition. In this cohort, ethionamide (ethA A381P) resistance would be missed in first-line drug-susceptible isolates, and streptomycin (gidB L79S) resistance may be missed due to an MIC close to the critical concentration. Subsequent inadequate treatment historically led to amplification of resistance and facilitated spread of the strains. Bedaquiline resistance was found in a small number of isolates, despite lack of exposure to the drug. The highly resistant clades also carry inhA promoter mutations, which arose after ethA and katG mutations. In these isolates, inhA promoter mutations do not alter drug resistance, suggesting a possible alternative role. Conclusion The presence of the ethA mutation in otherwise susceptible isolates from ethionamide-naïve patients demonstrates that known exposure is not an adequate indicator of drug susceptibility. Similarly, it is demonstrated that bedaquiline resistance can occur without exposure to the drug. Inappropriate treatment regimens, due to missed resistance, leads to amplification of resistance, and transmission. We put these results into the context of current WHO treatment regimens, underscoring the risks of treatment without knowledge of the full drug resistance profile.
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    Adverse drug reactions in South African patients receiving bedaquiline-containing tuberculosis treatment: an evaluation of spontaneously reported cases
    (2019-06-20) Jones, Jackie; Mudaly, Vanessa; Voget, Jacqueline; Naledi, Tracey; Maartens, Gary; Cohen, Karen
    Background Bedaquiline was recently introduced into World Health Organization (WHO)-recommended regimens for treatment of drug resistant tuberculosis. There is limited data on the long-term safety of bedaquiline. Because bedaquiline prolongs the QT interval, there are concerns regarding cardiovascular safety. The Western Cape Province in South Africa has an established pharmacovigilance programme: a targeted spontaneous reporting system which solicits reports of suspected adverse drug reactions (ADRs) in patients with HIV-1 and/or tuberculosis infection. Since 2015, bedaquiline has been included in the treatment regimens recommended for resistant tuberculosis in South Africa. We describe ADRs in patients on bedaquiline-containing tuberculosis treatment that were reported to the Western Cape Pharmacovigilance programme. Methods We reviewed reports of suspected ADRs and deaths received between March 2015 and June 2016 involving patients receiving bedaquiline-containing tuberculosis treatment. A multidisciplinary panel assessed causality, and categorised suspected ADRs using World Health Organisation-Uppsala Monitoring Centre system categories. “Confirmed ADRs” included all ADRs categorised as definite, probable or possible. Preventability was assessed using Schumock and Thornton criteria. Where a confirmed ADR occurred in a patient who died, the panel categorised the extent to which the ADR contributed to the patient’s death as follows: major contributor, contributor or non-contributor. Results Thirty-five suspected ADRs were reported in 32 patients, including 13 deaths. There were 30 confirmed ADRs, of which 23 were classified as “possible” and seven as “probable”. Bedaquiline was implicated in 22 confirmed ADRs in 22 patients. The most common confirmed ADR in patients receiving bedaquiline was QT prolongation (8 cases, 7 of which were severe). A fatal arrhythmia was suspected in 4 sudden deaths. These 4 patients were all taking bedaquiline together with other QT-prolonging drugs. There were 8 non-bedaquiline-associated ADRs, of which 7 contributed to deaths. Conclusions Confirmed ADRs in patients receiving bedaquiline reflect the known safety profile of bedaquiline. Quantifying the incidence and clinical consequences of severe QT-prolongation in patients receiving bedaquiline-containing regimens is a research priority to inform recommendations for patient monitoring in treatment programmes for drug resistant tuberculosis. Pharmacovigilance systems within tuberculosis treatment programmes should be supported and encouraged, to provide ongoing monitoring of treatment-limiting drug toxicity.
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    Pilot evaluation of a second-generation electronic pill box for adherence to Bedaquiline and antiretroviral therapy in drug-resistant TB/HIV co-infected patients in KwaZulu-Natal, South Africa
    (BioMed Central, 2018-04-11) Bionghi, N; Daftary, A; Maharaj, B; Msibi, Z; Amico, K R; Friedland, G; Orrell, C; Padayatchi, N; O’Donnell, M R
    Background: The introduction of Bedaquiline, the first new antimycobacterial drug in over 40 years, has highlighted the critical importance of medication adherence in drug-resistant tuberculosis (DR-TB) treatment to prevent amplified drug-resistance and derive sustained benefit. Real-time electronic dose monitoring (EDM) accurately measures adherence and allows for titration of adherence support for anti-retroviral therapy (ART). The goal of this study was to evaluate the accuracy and acceptability of a next-generation electronic pillbox (Wisepill RT2000) for Bedaquiline-containing TB regimens. Methods: Eligible patients were DR-TB/HIV co-infected adults hospitalized for the initiation of Bedaquilinecontaining treatment regimens in KwaZulu-Natal, South Africa. A one-way crossover design was used to evaluate levels of adherence and patient acceptance of EDM. Each patient was given a Wisepill device which was filled with ART, Levofloxacin or Bedaquiline over three consecutive weeks. Medication adherence was measured using Wisepill counts, patient-reported seven-day recall, and weekly pill count. An open-ended qualitative questionnaire at the end of the study evaluated participant acceptability of the Wisepill device. Results: We enrolled 21 DR-TB/HIV co-infected inpatients admitted for the initiation of Bedaquiline from August through September 2016. In aggregate patients were similarly adherent to Bedaquiline (100%) compared to Levofloxacin (100%) and ART (98.9%) by pill count. Wisepill was more sensitive (100%) compared to seven-day recall (0%) in detecting non-adherence events (p = 0.02). Patients reported positive experiences with Wisepill and expressed willingness to use the device during a full course of DR-TB treatment. There were no concerns about stigma, confidentiality, or remote monitoring. Conclusion: In this pilot study patients were highly adherent to Bedaquiline by all adherence measures. However, there was lower adherence to ART by pill count and Wisepill suggesting a possible challenge for adherence with ART. The use of EDM identified significantly more missed doses than seven-day recall. Wisepill was highly acceptable to DR-TB/HIV patients in South Africa, and is a promising modality to support and monitor medication adherence in complex treatment regimens.