Browsing by Author "Garcia-Prats, Anthony J."

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    Coronavirus disease 2019 (COVID-19) pharmacologic treatments for children : research priorities and approach to pediatric studies
    (Oxford University Press, 2020-06) Garcia-Prats, Anthony J.; Salazar-Austin, Nicole; Conway, James H.; Radtke, Kendra; LaCourse, Sylvia M.; Maleche-Obimbo, Elizabeth; Hesseling, Anneke C.; Savic, Rada M.; Nachman, Sharon
    Clinical trials of pharmacologic treatments of coronavirus disease 2019 (COVID-19) are being rapidly designed and implemented in adults. Children are often not considered during development of novel treatments for infectious diseases until very late. Although children appear to have a lower risk compared with adults of severe COVID-19 disease, a substantial number of children globally will benefit from pharmacologic treatments. It will be reasonable to extrapolate efficacy of most treatments from adult trials to children. Pediatric trials should focus on characterizing a treatment’s pharmacokinetics, optimal dose, and safety across the age spectrum. These trials should use an adaptive design to efficiently add or remove arms in what will be a rapidly evolving treatment landscape, and should involve a large number of sites across the globe in a collaborative effort to facilitate efficient implementation. All stakeholders must commit to equitable access to any effective, safe treatment for children everywhere.
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    Inclusion of key populations in clinical trials of new antituberculosis treatments : current barriers and recommendations for pregnant and lactating women, children, and HIV-infected persons
    (Public Library of Science, 2019) Gupta, Amita; Hughes, Michael D.; Garcia-Prats, Anthony J.; McIntire, Katherine; Hesseling, Anneke C.
    ENGLISH ABSTRACT: Pregnant women, children < 15 years old and, HIV-infected persons contribute approximately 20% of the global tuberculosis (TB) burden, with an estimated 216,000, 1,000,000, and 1,040,000 cases each year, respectively, yet these populations are currently largely excluded from TB clinical trials, leading to suboptimal treatment and poor access to new therapeutics. • Special considerations in these populations include specific TB disease spectrum and severity, lower sensitivity of commonly used TB diagnostic tests, potential differential drug dosing and treatment responses, drug–drug interactions, and challenges in acquiring high-quality data through clinical trials. • To counter the automatic exclusion of pregnant and lactating women that currently pervades the TB trial landscape, early discussions among trialists, pharmaceutical companies, maternal–child clinical experts, ethicists, and regulatory bodies are needed to address risks, benefits, and compelling rationale for inclusion. Reconsenting women when pregnancy occurs on a trial to allow continuation of study drug by informed choice is a practical and valuable approach to expand the currently limited evidence base. • Children tend to have less severe, often paucibacillary TB disease and may respond better to treatment than adults. Consequently, trials of shorter, less intense TB treatment regimens in children are needed; pharmacokinetic and safety studies should be initiated earlier and involve age groups in parallel rather than in an age-de-escalation approach. More rapid development of child-friendly drug formulations is needed. • All HIV-infected populations, including those with advanced disease, who are likely to be the intended population of the TB therapy, should be involved in Phase IIb and/or Phase III trials, as appropriate, to maximize knowledge of treatment, toxicities, drug– drug interactions, and outcomes.
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    Levofloxacin versus placebo for the prevention of tuberculosis disease in child contacts of multidrug-resistant tuberculosis : study protocol for a phase III cluster randomised controlled trial (TB-CHAMP)
    (BMC (part of Springer Nature), 2018-12-20) Seddon, James A.; Garcia-Prats, Anthony J.; Purchase, Susan E.; Osman, Muhammad; Demers, Anne-Marie; Hoddinott, Graeme; Crook, Angela M.; Owen-Powell, Ellen; Thomason, Margaret J.; Turkova, Anna; Gibb, Diana M.; Fairlie, Lee; Martinson, Neil; Schaaf, H. Simon; Hesseling, Anneke C.
    Background: Multidrug-resistant (MDR) tuberculosis (TB) presents a challenge for global TB control. Treating individuals with MDR-TB infection to prevent progression to disease could be an effective public health strategy. Young children are at high risk of developing TB disease following infection and are commonly infected by an adult in their household. Identifying young children with household exposure to MDR-TB and providing them with MDR-TB preventive therapy could reduce the risk of disease progression. To date, no trials of MDR-TB preventive therapy have been completed and World Health Organization guidelines suggest close observation with no active treatment. Methods: The tuberculosis child multidrug-resistant preventive therapy (TB-CHAMP) trial is a phase III cluster randomised placebo-controlled trial to assess the efficacy of levofloxacin in young child contacts of MDR-TB cases. The trial is taking place at three sites in South Africa where adults with MDR-TB are identified. If a child aged < 5 years lives in their household, we assess the adult index case, screen all household members for TB disease and evaluate any child aged < 5 years for trial eligibility. Eligible children are randomised by household to receive daily levofloxacin (15–20 mg/kg) or matching placebo for six months. Children are closely monitored for disease development, drug tolerability and adverse events. The primary endpoint is incident TB disease or TB death by one year after recruitment. We will enrol 1556 children from approximately 778 households with an average of two eligible children per household. Recruitment will run for 18–24 months with all children followed for 18 months after treatment. Qualitative and health economic evaluations are embedded in the trial. Discussion: If the TB-CHAMP trial demonstrates that levofloxacin is effective in preventing TB disease in young children who have been exposed to MDR-TB and that it is safe, well tolerated, acceptable and cost-effective, we would expect that that this intervention would rapidly transfer into policy.
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    Opportunities for mobile app–based adherence support for children with tuberculosis in South Africa
    (JMIR Publications, 2020) Morse, Rachel M.; Myburgh, Hanlie; Reubi, David; Archey, Ava E.; Busakwe, Leletu; Garcia-Prats, Anthony J.; Hesseling, Anneke C.; Jacobs, Stephanie; Mbaba, Sharon; Meyerson, Kyla; Seddon, James A.; Van Der Zalm, Marieke M.; Wademan, Dillon T.; Hoddinott, Graeme
    ENGLISH ABSTRACT: Tuberculosis is the number one infectious cause of death globally. Young children, generally those younger than 5 years, are at the highest risk of progressing from tuberculosis infection to tuberculosis disease and of developing the most severe forms of tuberculosis. Most current tuberculosis drug formulations have poor acceptability among children and require consistent adherence for prolonged periods of time. These challenges complicate children’s adherence to treatment and caregivers’ daily administration of the drugs. Rapid developments in mobile technologies and apps present opportunities for using widely available technology to support national tuberculosis programs and patient treatment adherence. Pilot studies have demonstrated that mobile apps are a feasible and acceptable means of enhancing children’s treatment adherence for other chronic conditions. Despite this, no mobile apps that aim to promote adherence to tuberculosis treatment have been developed for children. In this paper, we draw on our experiences carrying out research in clinical pediatric tuberculosis studies in South Africa. We present hypothetical scenarios of children’s adherence to tuberculosis medication to suggest priorities for behavioral and educational strategies that a mobile app could incorporate to address some of the adherence support gaps faced by children diagnosed with tuberculosis. We argue that a mobile app has the potential to lessen some of the negative experiences that children associate with taking tuberculosis treatment and to facilitate a more positive treatment adherence experience for children and their caregivers.
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    Pharmacokinetics and drug-drug interactions of abacavir and lamuvudine co-administered with antituberculosis drugs in HIV-positive children treated for multidrug-resistant tuberculosis
    (Frontiers Media S.A, 2021-10-08) Van der Laan, Louvina E.; Garcia-Prats, Anthony J.; Schaaf, H. Simon; Winckler, Jana L.; Draper, Heather; Norman, Jennifer; Wiesner, Lubbe; McIlleron, Helen; Denti, Paolo; Hesseling, Anneke C.
    Given the high prevalence of multidrug-resistant (MDR)-TB in high HIV burden settings, it is important to identify potential drug-drug interactions between MDR-TB treatment and widely used nucleoside reverse transcriptase inhibitors (NRTIs) in HIV-positive children. Population pharmacokinetic models were developed for lamivudine (n = 54) and abacavir (n = 50) in 54 HIV-positive children established on NRTIs; 27 with MDR-TB (combinations of high-dose isoniazid, pyrazinamide, ethambutol, ethionamide, terizidone, fluoroquinolones, and amikacin), and 27 controls without TB. Two-compartment models with first-order elimination and transit compartment absorption described both lamivudine and abacavir pharmacokinetics, respectively. Allometric scaling with body weight adjusted for the effect of body size. Clearance was predicted to reach half its mature value ∼2 (lamivudine) and ∼3 (abacavir) months after birth, with completion of maturation for both drugs at ∼2 years. No significant difference was found in key pharmacokinetic parameters of lamivudine and abacavir when co-administered with routine drugs used for MDR-TB in HIV-positive children.
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    Pharmacokinetics, optimal dosing, and safety of linezolid in children with multidrugresistant tuberculosis : combined data from two prospective observational studies
    (Public Library of Science, 2019) Garcia-Prats, Anthony J.; Schaaf, H. Simon; Draper, Heather R.; Garcia- Cremades, Maria; Winckler, Jana; Wiesner, Lubbe; Hesseling, Anneke C.; Savic, Rada M.
    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.
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    Presentation and outcome of culture-confirmed isoniazid-resistant rifampicin-susceptible tuberculosis in children
    (International Union Against Tuberculosis and Lung Disease, 2016) Garcia-Prats, Anthony J.; Du Plessis, L.; Draper, H. R.; Burger, A.; Seddon, J. A.; Zimri, K.; Hesseling, Anneke C.; Schaaf, H. Simon
    Setting: Isoniazid-resistant rifampicin-susceptible (HRRS) tuberculosis (TB) is the most prevalent form of drug-resistant TB globally, and may be a risk factor for poor outcomes. HRRS-TB in children has been poorly described. Objective: To characterize the clinical presentation, treatment, and clinical and microbiological outcomes, and factors associated with poor outcomes among children with culture-confirmed HRRS-TB. Design: Retrospective hospital-based cohort study. Results: Of the 72 children included, median age 50.1 months (IQR 21.5-102.5), 42% were male. Forty-four (51%) had a potential source case; only 13 were confirmed HRRS-TB. Twelve of 66 tested (17%) were HIV-infected, and 36 of 60 (60%) with pulmonary TB had severe disease. Seventy had treatment data; median total duration was 11.3 months (IQR 9-12.3); 25 (36%) initiated treatment with a 3-drug intensive phase; 52 (74%) received a fluoroquinolone. Of 63 with known outcome, 55 (88%) had a favourable outcome; 1 died and 3 had treatment failure. Ten had positive follow-up cultures at ≥2 months after starting treatment (17% of all PTB and 27% of those with follow-up culture data); older age (p=0.008), previous TB treatment (p=0.023) and severe PTB (p=0.018) were associated with failure to culture-convert at ≥2 months. Conclusions: Although overall outcomes were good, prolonged culture positivity and cases of treatment failure emphasize the need for additional attention to clinical management of children with HRRS-TB.
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    Treatment and outcomes in children with multidrug-resistant tuberculosis : a systematic review and individual patient data meta-analysis.
    (Public Library of Science, 2018-07-11) Harausz, Elizabeth P.; Garcia-Prats, Anthony J.; Law, Stephanie; Schaaf, H. Simon; Kredo, Tamara; Seddon, James A.; Menzies, Dick; Turkova, Anna; Achar, Jay; Amanullah, Farhana; Barry, Pennan; Becerra, Mercedes; Chan, Edward D.; Chan, Pei Chun; Chiotan, Domnica Ioana; Crossa, Aldo; Drobac, Peter C.; Fairlie, Lee; Falzon, Dennis; Flood, Jennifer; Gegia, Medea; Hicks, Robert M.; Isaakidis, Petros; Kadri, S. M.; Kampmann, Beate; Madhi, Shabir A.; Marais, Else; Mariandyshev, Andrei; Mendez-Echevarria, Ana; Moore, Brittany Kathryn; Nargiza, Parpieva; Ozere, Iveta; Padayatchi, Nesri; Ur-Rehman, Saleem; Rybak, Natasha; Santiago-Garcia, Begona; Shah, N. Sarita; Sharma, Sangeeta; Shim, Tae Sun; Skrahina, Alena; Soriano-Arandes, Antoni; Van Den Boom, Martin; Van Der Werf, Marieke J.; Van Der Werf, Tjip S.; Williams, Bhanu; Yablokova, Elena; Yim, Jae-Joon; Furin, Jennifer; Hesseling, Anneke C.
    Background: An estimated 32,000 children develop multidrug-resistant tuberculosis (MDR-TB; Mycobacterium tuberculosis resistant to isoniazid and rifampin) each year. Little is known about the optimal treatment for these children. Methods and findings: To inform the pediatric aspects of the revised World Health Organization (WHO) MDR-TB treatment guidelines, we performed a systematic review and individual patient data (IPD) meta-analysis, describing treatment outcomes in children treated for MDR-TB. To identify eligible reports we searched PubMed, LILACS, Embase, The Cochrane Library, PsychINFO, and BioMedCentral databases through 1 October 2014. To identify unpublished data, we reviewed conference abstracts, contacted experts in the field, and requested data through other routes, including at national and international conferences and through organizations working in pediatric MDR-TB. A cohort was eligible for inclusion if it included a minimum of three children (aged <15 years) who were treated for bacteriologically confirmed or clinically diagnosed MDR-TB, and if treatment outcomes were reported. The search yielded 2,772 reports; after review, 33 studies were eligible for inclusion, with IPD provided for 28 of these. All data were from published or unpublished observational cohorts. We analyzed demographic, clinical, and treatment factors as predictors of treatment outcome. In order to obtain adjusted estimates, we used a random-effects multivariable logistic regression (random intercept and random slope, unless specified otherwise) adjusted for the following covariates: age, sex, HIV infection, malnutrition, severe extrapulmonary disease, or the presence of severe disease on chest radiograph. We analyzed data from 975 children from 18 countries; 731 (75%) had bacteriologically confirmed and 244 (25%) had clinically diagnosed MDR-TB. The median age was 7.1 years. Of 910 (93%) children with documented HIV status, 359 (39%) were infected with HIV. When compared to clinically diagnosed patients, children with confirmed MDR-TB were more likely to be older, to be infected with HIV, to be malnourished, and to have severe tuberculosis (TB) on chest radiograph (p < 0.001 for all characteristics). Overall, 764 of 975 (78%) had a successful treatment outcome at the conclusion of therapy: 548/731 (75%) of confirmed and 216/244 (89%) of clinically diagnosed children (absolute difference 14%, 95% confidence interval [CI] 8%±19%, p < 0.001). Treatment was successful in only 56% of children with bacteriologically confirmed TB who were infected with HIV who did not receive any antiretroviral treatment (ART) during MDR-TB therapy, compared to 82% in children infected with HIV who received ART during MDR-TB therapy (absolute difference 26%, 95% CI 5%±48%, p = 0.006). In children with confirmed MDR-TB, the use of second-line injectable agents and high-dose isoniazid (15± 20 mg/kg/day) were associated with treatment success (adjusted odds ratio [aOR] 2.9, 95% CI 1.0±8.3, p = 0.041 and aOR 5.9, 95% CI 1.7±20.5, p = 0.007, respectively). These findings for high-dose isoniazid may have been affected by site effect, as the majority of patients came from Cape Town. Limitations of this study include the difficulty of estimating the treatment effects of individual drugs within multidrug regimens, only observational cohort studies were available for inclusion, and treatment decisions were based on the clinician's perception of illness, with resulting potential for bias. Conclusions: This study suggests that children respond favorably to MDR-TB treatment. The low success rate in children infected with HIV who did not receive ART during their MDR-TB treatment highlights the need for ART in these children. Our findings of individual drug effects on treatment outcome should be further evaluated.
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    Tuberculosis : opportunities and challenges for the 90-90-90 targets in HIV-infected children
    (International AIDS Society, 2015-12-02) Rabie, Helena; Frigati, Lisa; Hesseling, Anneke C.; Garcia-Prats, Anthony J.
    Introduction: In 2014 the Joint United Nations Programme on HIV/AIDS defined the ambitious 90 90 90 targets for 2020, in which 90% of people living with HIV must be diagnosed, 90% of those diagnosed should be on sustained therapy and 90% of those on therapy should have an undetectable viral load. Children are considered to be a key focus population for these targets. This review will highlight key components of the epidemiology, prevention and treatment of tuberculosis (TB) in HIV-infected children in the era of increasing access to antiretroviral therapy (ART) and their relation to the 90 90 90 targets. Discussion: The majority of HIV-infected children live in countries with a high burden of TB. In settings with a high burden of both diseases such as in sub-Saharan Africa, up to 57% of children diagnosed with and treated for TB are HIV-infected. TB results in substantial morbidity and mortality in HIV-infected children, so preventing TB and optimizing its treatment in HIV-infected children will be important to ensuring good long-term outcomes. Prevention of TB can be achieved by increasing access to ART to both children and adults, and appropriate provision of isoniazid preventative therapy. Co-treatment of HIV and TB is complicated by drug-drug interactions particularly due to the use of rifampicin; these may compromise virologic outcomes if appropriate corrective actions are not taken. There remain substantial operational challenges, and improved integration of paediatric TB and HIV services, including with antenatal and routine under-five care, is an important priority. Conclusions: TB may be an important barrier to achievement of the 90 90 90 targets, but specific attention to TB care in HIV-infected children may provide important opportunities to enhance the care of both TB and HIV in children.