Obesity is South Africa's new HIV epidemic

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In vitro optimization of crushed drug-sensitive antituberculosis medication when administered via a nasogastric tube

IMPORTANCE

The incidence of tuberculosis (TB) in intensive care units (ICUs) can be as high as 3% in high-burden settings, translating to more than 7,500 patients admitted to the ICU annually. In resource-limited settings, the lack or absence of intravenous formulations of drug-sensitive antituberculosis medications necessitates healthcare practitioners to crush, dissolve, and administer the drugs to critically ill patients via a nasogastric tube (NGT). This off-label practice has been linked to plasma concentrations below the recommended target concentrations, particularly of rifampicin and isoniazid, leading to clinical failure and the development of drug resistance. Optimizing the delivery of crushed drug-sensitive antituberculosis medication via the NGT to critically ill patients is of utmost importance.

Pharmacokinetics and safety of first-line tuberculosis drugs rifampin, isoniazid, ethambutol, and pyrazinamide during pregnancy and postpartum: results from IMPAACT P1026s

Physiological changes during pregnancy may alter the pharmacokinetics (PK) of antituberculosis drugs. The International Maternal Pediatric Adolescent AIDS Clinical Trials Network P1026s was a multicenter, phase IV, observational, prospective PK and safety study of antiretroviral and antituberculosis drugs administered as part of clinical care in pregnant persons living with and without HIV. We assessed the effects of pregnancy on rifampin, isoniazid, ethambutol, and pyrazinamide PK in pregnant and postpartum (PP) persons without HIV treated for drug-susceptible tuberculosis disease. Daily antituberculosis treatment was prescribed following World Health Organization-recommended weight-band dosing guidelines. Steady-state 12-hour PK profiles of rifampin, isoniazid, ethambutol, and pyrazinamide were performed during second trimester (2T), third trimester (3T), and 2-8 of weeks PP. PK parameters were characterized using noncompartmental analysis, and comparisons were made using geometric mean ratios (GMRs) with 90% confidence intervals (CI). Twenty-seven participants were included: 11 African, 9 Asian, 3 Hispanic, and 4 mixed descent. PK data were available for 17, 21, and 14 participants in 2T, 3T, and PP, respectively. Rifampin and pyrazinamide AUC0-24 and C max in pregnancy were comparable to PP with the GMR between 0.80 and 1.25. Compared to PP, isoniazid AUC0-24 was 25% lower and C max was 23% lower in 3T. Ethambutol AUC0-24 was 39% lower in 3T but limited by a low PP sample size. In summary, isoniazid and ethambutol concentrations were lower during pregnancy compared to PP concentrations, while rifampin and pyrazinamide concentrations were similar. However, the median AUC0-24 for rifampin, isoniazid, and pyrazinamide met the therapeutic targets. The clinical impact of lower isoniazid and ethambutol exposure during pregnancy needs to be determined.

An LC-MS/MS method for the simultaneous quantitation of sulfasalazine and sulfapyridine in human placenta

Sulfasalazine has been identified as a candidate molecule to be investigated as an intervention to treat preterm pre-eclampsia during pregnancy. However, placental exposure of sulfasalazine and its systemically absorbed metabolite, sulfapyridine, is unknown. A robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously quantitate these analytes in human placenta with an application to a pilot clinical trial. The placental tissue was homogenised using a water:methanol (1:1, v/v) mixture, followed by sample extraction using both protein precipitation and solid phase extraction. Sulfasalazine-d4 and sulfapyridine-d4 were used as internal standards. An Agilent Poroshell EC-C18 (3.0 ×100 mm, 2.7 µm) column was used for chromatographic separation, with gradient elution employed at a flow rate of 0.450 mL/min over a total run time of seven minutes. The mobile phases consisted of water with 0.1% formic acid (mobile phase A) and acetonitrile:methanol (90:10, v/v) with 0.1% formic acid (mobile phase B). A Shimadzu-8040 mass spectrometer was operated in multiple reaction monitoring (MRM) mode using positive electrospray ionisation (ESI). For both analytes, the assay was validated over the range 30-30,000 ng/mL, or 150-150,000 ng/g. During inter-day validations (n = 18), the average accuracies of quality controls ranged from 101.6% to 112.7% with corresponding precisions of 4.4-6.7% for sulfasalazine, and from 97.4% to 108.4%, with corresponding precisions of 3.7-10.0% for sulfapyridine. No significant matrix effects were observed, and the method proved to be sensitive and specific for both analytes. This study presents the first validated analytical method for quantifying sulfasalazine and sulfapyridine in human placenta as part of a pilot clinical trial to generate preliminary data on its pharmacokinetics and efficacy as in intervention for preterm pre-eclampsia.

Long-acting antiretrovirals and HIV treatment adherence

Intramuscular injection of long-acting cabotegravir and rilpivirine is a novel, long-acting antiretroviral therapy (ART) combination approved for use as a fully suppressive regimen for people living with HIV. Long-acting cabotegravir with rilpivirine ART has reduced required dosing frequency from once daily to once every month or every 2 months injections. This new era of long-acting ART, which includes other antiretrovirals and formulations in various stages of clinical development, holds tremendous promise to change the standard of HIV treatment. Although long-acting ART has high potential to be revolutionary in the landscape of HIV care, prevention, and treatment cascade, more data are needed to substantiate its efficacy and cost-effectiveness among patients at risk of non-adherence and across age groups, pregnancy, and post partum. Advocacy efforts and policy changes to optimise a sustained, high-quality, equitable reach of long-acting ART, especially in low-income and middle-income countries where most people living with HIV reside, are needed to realise the full benefits of long-acting ART.

Blood and cerebrospinal fluid biomarker changes in patients with HIV-associated neurocognitive impairment treated with lithium: analysis from a randomised placebo-controlled trial

HIV-associated neurocognitive disorders (HAND) persist in the era of antiretroviral therapy (ART). Thus, ART does not completely halt or reverse the pathological processes behind HAND. Adjuvant mitigating treatments are, therefore, prudent. Lithium treatment is known to promote neuronal brain-derived neurotrophic factors (BDNF). Lithium is also an inhibitor of glycogen synthase kinase-3 beta (GSK-3-β). We analyzed biomarkers obtained from participants in a randomized placebo-controlled trial of lithium in ART-treated individuals with moderate or severe HAND. We assayed markers at baseline and 24 weeks across several pathways hypothesized to be affected by HIV, inflammation, or degeneration. Investigated biomarkers included dopamine, BDNF, neurofilament light chain, and CD8 + lymphocyte activation (CD38 + HLADR +). Alzheimer's Disease (AD) biomarkers included soluble amyloid precursor protein alpha and beta (sAPPα/β), Aβ38, 40, 42, and ten other biomarkers validated as predictors of mild cognitive impairment and progression in previous studies. These include apolipoprotein C3, pre-albumin, α1-acid glycoprotein, α1-antitrypsin, PEDF, CC4, ICAM-1, RANTES, clusterin, and cystatin c. We recruited 61 participants (placebo = 31; lithium = 30). The age baseline mean was 40 (± 8.35) years and the median CD4 + T-cell count was 498 (IQR: 389-651) cells/μL. Biomarker concentrations between groups did not differ at baseline. However, both groups' blood dopamine levels decreased significantly after 24 weeks (adj. p < 002). No other marker was significantly different between groups, and we concluded that lithium did not confer neuroprotection following 24 weeks of treatment. However, the study was limited in duration and sample size.

Urine tenofovir-monitoring predicts HIV viremia in patients treated with high genetic-barrier regimens

OBJECTIVE

Access to viral load measurements is constrained in resource-limited settings. A lateral flow urine tenofovir (TFV) rapid assay (UTRA) for patients whose regimens include TFV offers an affordable approach to frequent adherence monitoring.

DESIGN

We conducted a cross-sectional study of patients to assess the utility of UTRA to predict virologic failure, defined as a viral load greater than 400 copies/ml.

METHODS

We assessed urine TFV among 113 participants at increased risk of viral failure (who had previous viral failure on this regimen or had previously been ≥30 days out of care), comparing low genetic-barrier efavirenz (EFV) regimens (n = 60) to dolutegravir (DTG)-boosted or ritonavir-boosted protease inhibitor (PI/r)-based high genetic-barrier regimens (n = 53). Dried blood spots (DBS) for TFV-diphosphate and plasma for TFV concentrations were collected, with drug resistance assessed if viral failure present.

RESULTS

Among 113 participants, 17 of 53 received DTG or PI/r had viral failure at the cross-sectional visit, with 11 (64.7%) demonstrating an undetectable urine TFV; the negative-predictive value (NPV) of undetectable UTRA for viral failure was 85% (34/40); none of the 16 sequenced had dual class drug resistance. In those treated with EFV regimens the sensitivity was lower, as only 1 (4.8%) of 21 with viral failure had an undetectable UTRA (P < 0.001).

CONCLUSIONS

Urine tenofovir-testing had a high negative-predictive value for viral failure in patients treated with DTG or ritonavir-boosted protease inhibitor regimens, where viral failure was largely explained by poor drug adherence. Frequent monitoring with inexpensive lateral flow urine TFV testing should be investigated prospectively in between viral load visits to improve viral load suppression on DTG-based first-line therapy in resource-limited settings.

Drug Resistance, Rather than Low Tenofovir Levels in Blood or Urine, Is Associated with Tenofovir, Emtricitabine, and Efavirenz Failure in Resource-Limited Settings

The high cost of viral load (VL) testing limits its use for antiretroviral therapy (ART) adherence support. A low-cost lateral flow urine tenofovir (TFV) rapid assay predicts pre-exposure prophylaxis breakthroughs, but has not yet been investigated in HIV treatment. We therefore evaluated its utility in a pilot cross-sectional study of TFV-containing ART recipients at an increased risk of virologic failure (VF). Participants who had a treatment interruption ≥30 days or had ≥1 episode of viremia (VL ≥400 copies/mL) in the previous year were recruited from a public health setting in Cape Town, South Africa. Self-reported adherence data were collected, the urine TFV assay performed, and concurrent TFV-diphosphate analyzed in dried blood spots. VL testing was done concurrently and, if viremic, genotypic HIV drug resistance testing was performed. Of 48 participants, 18 (37.5%) had VL (>400 copies/mL) at the time of the study, including 16 of 39 receiving efavirenz (EFV), 2 of 6 receiving protease inhibitors, and 0 of 3 receiving dolutegravir. Resistance testing succeeded in 17/18, of which 14 had significant mutations compromising ≥2 agents of the current EFV-based regimen. Of these 14, all had detected urine TFV. Urine TFV was undetectable in two out of three without regimen-relevant resistance; p = .02. In participants on EFV-based regimens returning to care, VF was largely due to viral resistance, where detectable urine TFV had 100% sensitivity (14/14 participants) in predicting resistance. Conversely, when undetectable, the urine-based assay could be used to preclude participants with poor adherence from undergoing costly HIV drug resistance testing.

Abacavir dosing in neonates from birth to 3 months of life: a population pharmacokinetic modelling and simulation study

BACKGROUND

No evidence-based optimal dosing guidance is available for abacavir liquid formulation use from birth. We used abacavir pharmacokinetic data from neonates and infants to determine an exact abacavir dosing strategy (mg/kg) for infants aged 0-3 months and to propose dosing by WHO weight band for neonates.

METHODS

Abacavir pharmacokinetic and safety data were pooled from three completed studies (1997-2020): PACTG 321 (USA), the Tygerberg Cohort (South Africa), and IMPAACT P1106 (South Africa). PACTG 321 and the Tygerberg Cohort were performed in neonates exposed to HIV receiving a single dose of abacavir. IMPAACT P1106 included predominantly low birthweight (<2500 g) infants on antiretroviral therapy enrolled when they were younger than 3 months. We developed a population pharmacokinetic model and performed simulations to achieve abacavir exposures (area under the curve for 0-12 h) within the target range of 3·2-25·2 μg·h/mL, previously reported in older children.

FINDINGS

45 infants contributed 308 abacavir concentrations; 21 neonates were younger than 15 days. At first pharmacokinetic assessment, median postnatal age for PACTG 321 was 1 day and median bodyweight was 3·1 kg; for the Tygerberg Cohort it was 10 days and 3·3 kg; and for IMPAACT P1106 it was 73 days and 3·8 kg. Our model predicted a slow abacavir clearance of 2·51 mL/min per kg at birth, which doubled by 4 weeks of age. Therapeutic targets were achieved with exact abacavir doses of 2·0 mg/kg twice daily from 0 weeks to 4 weeks and 4·0 mg/kg twice daily from 4 weeks to 12 weeks. A fixed weight-band dosing strategy of 8 mg (for 2-3 kg), 10 mg (3-4 kg), and 12 mg (4-5 kg) abacavir twice daily achieved target exposures throughout the first 4 weeks of life without the need for dose adjustment due to age or bodyweight changes. No adverse events of grade 3 or higher were related to abacavir.

INTERPRETATION

Integration of these dosing strategies into national and international guidelines for the abacavir liquid formulation will expand antiretroviral options from birth and simplify the clinical management of neonates with HIV.

FUNDING

National Institute of Allergy and Infectious Diseases, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institute of Mental Health, and the Collaborative Initiative for Paediatric HIV Education and Research Programme.

An International Adult Guideline for Making Clozapine Titration Safer by Using Six Ancestry-Based Personalized Dosing Titrations, CRP, and Clozapine Levels

This international guideline proposes improving clozapine package inserts worldwide by using ancestry-based dosing and titration. Adverse drug reaction (ADR) databases suggest that clozapine is the third most toxic drug in the United States (US), and it produces four times higher worldwide pneumonia mortality than that by agranulocytosis or myocarditis. For trough steady-state clozapine serum concentrations, the therapeutic reference range is narrow, from 350 to 600 ng/mL with the potential for toxicity and ADRs as concentrations increase. Clozapine is mainly metabolized by CYP1A2 (female non-smokers, the lowest dose; male smokers, the highest dose). Poor metabolizer status through phenotypic conversion is associated with co-prescription of inhibitors (including oral contraceptives and valproate), obesity, or inflammation with C-reactive protein (CRP) elevations. The Asian population (Pakistan to Japan) or the Americas' original inhabitants have lower CYP1A2 activity and require lower clozapine doses to reach concentrations of 350 ng/mL. In the US, daily doses of 300-600 mg/day are recommended. Slow personalized titration may prevent early ADRs (including syncope, myocarditis, and pneumonia). This guideline defines six personalized titration schedules for inpatients: 1) ancestry from Asia or the original people from the Americas with lower metabolism (obesity or valproate) needing minimum therapeutic dosages of 75-150 mg/day, 2) ancestry from Asia or the original people from the Americas with average metabolism needing 175-300 mg/day, 3) European/Western Asian ancestry with lower metabolism (obesity or valproate) needing 100-200 mg/day, 4) European/Western Asian ancestry with average metabolism needing 250-400 mg/day, 5) in the US with ancestries other than from Asia or the original people from the Americas with lower clozapine metabolism (obesity or valproate) needing 150-300 mg/day, and 6) in the US with ancestries other than from Asia or the original people from the Americas with average clozapine metabolism needing 300-600 mg/day. Baseline and weekly CRP monitoring for at least four weeks is required to identify any inflammation, including inflammation secondary to clozapine rapid titration.

Post-tuberculous lung disease: should we be using Theophylline?

Tuberculosis affects 10 million people and over 320,000 South Africans every year. A significant proportion of patients treated for tuberculosis develop post-tuberculous lung disease (PTBLD), a disease of chronic respiratory impairment for which there is a lack of affordable treatment options. PTBLD a heterogenous disorder that shares phenotypical features with chronic obstructive lung disease, bronchiectasis, lung fibrosis and destruction as well as pulmonary hypertension. There remains a paucity of proven pharmacotherapy for the management of PTBLD. Theophylline, a widely available and affordable medicine that has largely fell out of favour in high-income settings due to its toxicity and narrow therapeutic index, may be repositioned for the treatment of PTBLD. In this review, we unpack the potential role of theophylline in the management of PTBLD by reviewing the evidence for its bronchodilatory, anti-inflammatory and potential pleotrophic effects.

Artemisia Spp. Derivatives for COVID-19 Treatment: Anecdotal Use, Political Hype, Treatment Potential, Challenges, and Road Map to Randomized Clinical Trials

The world is currently facing a novel COVID-19 pandemic caused by SARS-CoV-2 that, as of July 12, 2020, has caused a reported 12,322,395 cases and 556,335 deaths. To date, only two treatments, remdesivir and dexamethasone, have demonstrated clinical efficacy through randomized controlled trials (RCTs) in seriously ill patients. The search for new or repurposed drugs for treatment of COVID-19 continues. We have witnessed anecdotal use of herbal medicines, including Artemisia spp. extracts, in low-income countries, and exaggerated claims of their efficacies that are not evidence based, with subsequent political controversy. These events highlight the urgent need for further research on herbal compounds to evaluate efficacy through RCTs, and, when efficacious compounds are identified, to establish the active ingredients, develop formulations and dosing, and define pharmacokinetics, toxicology, and safety to enable drug development. Derivatives from the herb Artemisia annua have been used as traditional medicine over centuries for the treatment of fevers, malaria, and respiratory tract infections. We review the bioactive compounds, pharmacological and immunological effects, and traditional uses for Artemisia spp. derivatives, and discuss the challenges and controversies surrounding current efforts and the scientific road map to advance them to prevent or treat COVID-19.

Clinical evolution, management and outcomes of patients with COVID-19 admitted at Tygerberg Hospital, Cape Town, South Africa: a research protocol

INTRODUCTION

The outbreak of the SARS-CoV-2 virus causing COVID-19, declared a global pandemic by the WHO, is a novel infection with a high rate of morbidity and mortality. In South Africa, 55 421 cases have been confirmed as of 10 June 2020, with most cases in the Western Cape Province. Coronavirus leaves us in a position of uncertainty regarding the best clinical approach to successfully manage the expected high number of severely ill patients with COVID-19. This presents a unique opportunity to gather data to inform best practices in clinical approach and public health interventions to control COVID-19 locally. Furthermore, this pandemic challenges our resolve due to the high burden of HIV and tuberculosis (TB) in our country as data are scarce. This study endeavours to determine the clinical presentation, severity and prognosis of patients with COVID-19 admitted to our hospital.

METHODS AND ANALYSIS

The study will use multiple approaches taking into account the evolving nature of the COVID-19 pandemic. Prospective observational design to describe specific patterns of risk predictors of poor outcomes among patients with severe COVID-19 admitted to Tygerberg Hospital. Data will be collected from medical records of patients with severe COVID-19 admitted at Tygerberg Hospital. Using the Cox proportional hazards model, we will investigate the association between the survival time of patients with COVID-19 in relation to one or more of the predictor variables including HIV and TB.

ETHICS AND DISSEMINATION

The research team obtained ethical approval from the Health Research Ethics Committee of the Faculty of Medicine and Health Sciences, Stellenbosch University and Research Committee of the Tygerberg Hospital. All procedures for the ethical conduct of scientific investigation will be adhered to by the research team. The findings will be disseminated in clinical seminars, scientific forums and conferences targeting clinical care providers and policy-makers.

Adverse Drug Reactions in Paediatric In-Patients in a South African Tertiary Hospital

BACKGROUND

The prevalence of adverse drug reaction (ADR) rates in children in sub-Saharan Africa is unknown.

OBJECTIVES

To describe the prevalence of ADRs in paediatric in-patients at a tertiary hospital in South Africa.

METHODS

This is a prospective study during a 3-month study period. Data collected included age, sex, diagnosis, medicines received and ADRs experienced. Causality were assessed, using the 10-question Naranjo probability scale and classified according to the Hartwig severity scale.

RESULTS

There were 61 ADRs in 18.4% (52 of 282) of patients. Median age of patients was 1.4 years (interquartile range: 0.5-5.3 years). ADR was the primary admission reason in 31%. The majority of the ADRs were moderate 45.9% (28 of 61), and only 11.5% severe (7 of 61). Paediatric oncology patients suffered significantly more ADRs (56.5%; 13 of 23) [odds ratio 7.3 (3.0-17.9), p < 0.01], followed by HIV-infected patients (42.9%; 9 of 21).

CONCLUSION

The prevalence of ADRs was 18.4%, while 31% was the reason for admission.

Simulating therapeutic drug monitoring results for dose individualisation to maintain investigator blinding in a randomised controlled trial

Background

Therapeutic drug monitoring (TDM) is essential practice when dosing drugs with a narrow therapeutic index in order to achieve a plasma drug concentration within a narrow target range above the efficacy concentration but below the toxicity concentration. However, TDM with dose individualisation is challenging during a double-blind clinical trial with laboratory staff and investigators blinded to treatment arm allocation.

Methods

Drug concentrations were simulated for participants in the placebo arm by an unblinded independent statistician, utilising the measured values from the treatment arm participants. Simulated and actual concentrations were re-blinded and passed on to a dose-adjusting investigator, who made dose adjustment recommendations but was not directly responsible for clinical care of participants.

Results

A total of 257 sham lithium plasma concentrations were simulated utilising 242 true lithium plasma concentrations in real time as the trial progressed. The simulated values had a median (interquartile range) of 0.59 (0.46, 0.72) compared to 0.53 (0.39, 0.72) in the treatment arm. Blinding of the laboratory staff and dose-adjusting investigator was maintained successfully.

Conclusions

We succeeded in simulating sham lithium plasma concentrations while maintaining blinding. Our simulated values have a smaller range than the observed data, which can be explained by the challenges with respect to drug adherence and dose timing that were experienced.

Trial registration

Pan African Clinical Trials Registry, PACTR201310000635418. Registered on 30 August 2013.

Model-based approach to dose optimization of lopinavir/ritonavir when co-administered with rifampicin

AIMS

Rifampicin, a key component of antitubercular treatment, profoundly reduces lopinavir concentrations. The aim of this study was to develop an integrated population pharmacokinetic model accounting for the drug-drug interactions between lopinavir, ritonavir and rifampicin, and to evaluate optimal doses of lopinavir/ritonavir when co-administered with rifampicin.

METHODS

Steady-state pharmacokinetics of lopinavir and ritonavir were sequentially evaluated after the introduction of rifampicin and gradually escalating the dose in a cohort of 21 HIV-infected adults. Intensive pharmacokinetic sampling was performed after each dose adjustment following a morning dose administered after fasting overnight. A population pharmacokinetic analysis was conducted using NONMEM 7.

RESULTS

A simultaneous integrated model was built. Rifampicin reduced the oral bioavailability of lopinavir and ritonavir by 20% and 45% respectively, and it increased their clearance by 71% and 36% respectively. With increasing concentrations of ritonavir, clearance of lopinavir decreased in an E(max) relationship. Bioavailability was 42% and 45% higher for evening doses compared with morning doses for lopinavir and ritonavir, respectively, while oral clearance of both drugs was 33% lower overnight. Simulations predicted that 99.5% of our patients receiving doubled doses of lopinavir/ritonavir achieve morning trough concentrations of lopinavir > 1 mg l(-1) during rifampicin co-administration, and 95% of those weighing less than 50 kg achieve this target already with 600/150 mg doses of lopinavir/ritonavir.

CONCLUSIONS

The model describes the drug-drug interactions between lopinavir, ritonavir and rifampicin in adults. The higher trough concentrations observed in the morning were explained by both higher bioavailability with the evening meal and lower clearance overnight.