Immunogenicity dynamics and covariate effects after satralizumab administration predicted with a hidden Markov model.

Immunogenicity is the propensity of a therapeutic protein to generate an immune response to itself. While reporting of antidrug antibodies (ADAs) is increasing, model-based analysis of such data is seldom performed. Model-based characterization of factors affecting the emergence and dissipation of ADAs may inform drug development and/or improve understanding in clinical practice. This analysis aimed to predict ADA dynamics, including the potential influence of individual covariates, following subcutaneous satralizumab administration. Satralizumab is a humanized IgG2 monoclonal recycling IL-6 receptor antagonist antibody approved for treating neuromyelitis optica spectrum disorder (NMOSD). Longitudinal pharmacokinetic (PK) and ADA data from 154 NMOSD patients in two pivotal Phase 3 studies (NCT02028884, NCT02073279) and PK data from one Phase 1 study (SA-001JP) in 72 healthy volunteers were available for this analysis. An existing population PK model was adapted to derive steady-state concentration without ADA for each patient. A mixed hidden Markov model (mHMM) was developed whereby three different states were identified: one absorbing Markov state for non-ADA developer, and two dynamic and inter-connected Markov states-transient ADA negative and positive. Satralizumab exposure and body mass index impacted transition probabilities and, therefore, the likelihood of developing ADAs. In conclusion, the mHMM model was able to describe the time course of ADA development and identify patterns of ADA development in NMOSD patients following treatment with satralizumab, which may allow for the formulation of strategies to reduce the emergence or limit the impact of ADA in the clinical setting.

Relative Bioavailability of Dolutegravir (DTG) and Emtricitabine/Tenofovir Alafenamide Fumarate (F/TAF) Administered as Paediatric Tablet Formulations in Healthy Volunteers.

BACKGROUND AND OBJECTIVE: Within the UNIVERSAL project (RIA2019PD-2882) we aim to develop a paediatric dolutegravir (DTG)/emtricitabine (FTC or F)/tenofovir alafenamide (TAF) fixed-dose combination. To inform dosing of this study, we undertook a relative bioavailability (RBA) study in healthy volunteers to investigate a potential pharmacokinetic effect when paediatric formulations of DTG and F/TAF are taken together. METHODS: Participants received all of the following treatments as paediatric formulations in randomised order: a single dose of 180/22.5 mg F/TAF; a single dose of 30 mg DTG; a single dose of 180/22.5 mg F/TAF plus 30 mg DTG. Blood concentrations of DTG, FTC, TAF, and tenofovir (TFV) were measured over 48 h post-dose. If the 90% confidence intervals (CIs) of the geometric least squares mean (GLSM) ratios of area under the curve (AUC) and maximum concentration (Cmax) of each compound were within 0.70-1.43, we considered this as no clinically relevant PK interaction. RESULTS: A total of 15 healthy volunteers were included. We did not observe a clinically relevant PK interaction between the paediatric DTG and F/TAF formulations for the compounds DTG, FTC, and TFV. For TAF, the lower boundaries of the 90% CIs of the GLSM ratios of the AUC0-∞ and Cmax fell outside our acceptance criteria of 0.70-1.43. CONCLUSIONS: Although TAF AUC and Cmax 90% CIs fell outside the pre-defined criteria (0.62-1.11 and 0.65-1.01, respectively), no consistent effect on TAF PK was observed, likely due to high inter-subject variability. Moreover, there are several reasons to rely on TFV exposure as being more clinically relevant than TAF exposure. Therefore, we found no clinically relevant interactions in this study.

Pharmacokinetics and safety of coformulated bictegravir, emtricitabine, and tenofovir alafenamide in children aged 2 years and older with virologically suppressed HIV: a phase 2/3, open-label, single-arm study.

BACKGROUND: Coformulated bictegravir, emtricitabine, and tenofovir alafenamide is a single-tablet regimen and was efficacious and well tolerated in children and adolescents with HIV (aged 6 years to <18 years) in a 48-week phase 2/3 trial. In this study, we report data from children aged at least 2 years and weighing 14 kg to less than 25 kg. METHODS: We conducted this open-label, multicentre, multicohort, single-arm study in South Africa, Thailand, Uganda, and the USA. Participants were virologically suppressed children with HIV, aged at least 2 years, weighing 14 kg to less than 25 kg. Participants received bictegravir (30 mg), emtricitabine (120 mg), and tenofovir alafenamide (15 mg) once daily, switching to bictegravir (50 mg), emtricitabine (200 mg), and tenofovir alafenamide (25 mg) upon attaining a bodyweight of at least 25 kg. The study included pharmacokinetic evaluation at week 2 to confirm the dose of coformulated bictegravir, emtricitabine, and tenofovir alafenamide for this weight band by comparing with previous adult data. Primary outcomes were bictegravir area under the curve over the dosing interval (AUCtau) and concentration at the end of the dosing interval (Ctau) at week 2, and incidence of treatment-emergent adverse events and laboratory abnormalities until the end of week 24 in all participants who received at least one dose of bictegravir, emtricitabine, and tenofovir alafenamide. This study is registered with ClinicalTrials.gov, NCT02881320. FINDINGS: Overall, 22 participants were screened (from Nov 14, 2018, to Jan 11, 2020), completed treatment with bictegravir, emtricitabine, and tenofovir alafenamide (until week 48), and entered an extension phase. The geometric least squares mean (GLSM) ratio for AUCtau for bictegravir was 7·6% higher than adults (GLSM ratio 107·6%, 90% CI 96·7-119·7); Ctau was 34·6% lower than adults (65·4%, 49·1-87·2). Both parameters were within the target exposure range previously found in adults, children, or both". Grade 3-4 laboratory abnormalities occurred in four (18%) participants by the end week 24 and six (27%) by the end of week 48. Drug-related adverse events occurred in three participants (14%) by the end of week 24 and week 48; none were severe. No Grade 3-4 adverse events, serious adverse events, or adverse events leading to discontinuation occurred by the end of week 24 and week 48. INTERPRETATION: Data support the use of single-tablet coformulated bictegravir (30 mg), emtricitabine (120 mg), and tenofovir alafenamide (15 mg) for treatment of HIV in children aged at least 2 years and weighing 14 kg to less than 25 kg. FUNDING: Gilead Sciences.

Access to novel anti-diabetic agents in resource limited settings: A brief commentary.

The prevalence of diabetes mellitus is increasing in resource limited settings. Simultaneously, there has been an increase in the number of novel therapies for the management of diabetes mellitus. However, use of novel antidiabetic therapies is limited because of major market access challenges in resource limited settings. Niching products to those patients with the highest absolute risk for major adverse cardiovascular outcomes, and thus most likely to benefit from the therapy, are less likely to have negative budget impact for funders. To improve access, and reduce morbidity and mortality, requires alignment amongst key stakeholders including patient advocacy groups, health care professional councils, national departments of health, the pharmaceutical industry, treasury and finance departments.

Optimal dosing of gliclazide-A model-based approach.

Gliclazide was approved as a treatment for type 2 diabetes in an era before model-based drug development, and consequently, the recommended doses were not optimised with modern methods. To investigate various dosing regimens of gliclazide, we used publicly available data to characterise the dose-response relationship using pharmacometric models. A literature search identified 21 published gliclazide pharmacokinetic (PK) studies with full profiles. These were digitised, and a PK model was developed for immediate- (IR) and modified-release (MR) formulations. Data from a gliclazide dose-ranging study of postprandial glucose were used to characterise the concentration-response relationship using the integrated glucose-insulin model. Simulations from the full model showed that the maximum effect was 44% of the patients achieving HbA1c <7%, with 11% experiencing glucose <3 mmol/L and the most sensitive patients (i.e., 5% most extreme) experiencing 35 min of hypoglycaemia. Simulations revealed that the recommended IR dose (320 mg) was appropriate with no efficacy gain with increased dose. However, the recommended dose for the MR formulation may be increased to 270 mg, with more patients achieving HbA1c goals (i.e., HbA1c <7%) without a hypoglycaemic risk higher than the resulting risk from the recommended IR dose.

Real-world evidence and product development: Opportunities, challenges and risk mitigation.

Real-world evidence (RWE) is derived from real-world data (RWD) sources including electronic health records, claims data, registries (disease, product) and pragmatic clinical trials. The importance of RWE derived from RWD has been once again demonstrated during the coronavirus disease 2019 (COVID-19) pandemic, as it can improve patient care by complementing information obtained from traditional clinical trial programs. Additionally, RWE can generate insights into disease mechanisms, epidemiology, patient flows in and out of healthcare systems, and drivers and barriers to optimal clinical care in real-world settings. Identifying unmet medical needs is crucial as it often can inform which investigational new drugs enter clinical trial testing, and RWE studies from hospital settings have contributed substantial progress here. RWE can also optimize the design of clinical studies, inform benefit risk assessments and use networks of pragmatic studies to help with clinical trial feasibilities and eventual trial initiation. The challenges of RWD include data quality, reproducibility and accuracy which may affect validity. RWD and RWE must be fit for purpose and one must be cognizant of inherent biases.

The therapeutic management of South African dyslipidaemic patients at very high cardiovascular risk (CARDIO TRACK): a cross-sectional study.

BACKGROUND: Dyslipidaemia is a major modifiable risk factor for atherosclerotic cardiovascular disease. At the time the study was conducted, guidelines recommended a low-density lipoprotein cholesterol (LDL-C) target of less than 1.8 mmol/l and a reduction of at least 50% if the baseline LDL-C was between 1.8 and 3.5 mmol/l in patients with either very high cardiovascular risk or established atherosclerosis. In South Africa, there is a paucity of data on attainment of LDL-C goal in patients with very high cardiovascular risk who are on maximum tolerated statin with or without ezetimibe. OBJECTIVE: The aim was to assess the percentage of very high cardiovascular risk South African patients with dyslipidaemia not reaching an LDL-C goal of less than 1.8 mmol/l, despite maximum tolerated statin with or without ezetimibe. METHODS: This was a multi-centre, observational, cross-sectional study conducted at 15 private healthcare sector sites and one public sector site. Adults (> 18 years) with very high cardiovascular risk of familial hypercholesterolaemia receiving stable, maximum-tolerated statin therapy for at least four weeks prior to their latest lipid profile were enrolled into the study, and electronic case report forms were completed after written informed consent was provided. LDL-C goal attainment was modelled, first assuming an increase in the statin dose to the registered maximum, followed by the addition of ezetimibe or a PCSK9-inhibitor. RESULTS: In total, 507 patients were screened, of whom 492 were eligible for study participation. One patient was excluded from the analysis because of a missing LDL-C value. Most participants were male (male 329, 67%; female 162, 33%). Most patients were either obese (223, 46.0%) or overweight (176, 36.3%). Hypertension and diabetes mellitus were frequent co-morbidities and were found in 381 (77.6%) and 316 (64.4%) patients, respectively. Eighty (16.3%) patients reported current smoking. Only 68 (13.8%) patients were taking ezetimibe in addition to a statin. Reasons for not using ezetimibe included no requirement for ezetimibe in the opinion of the treating physician (229, 48.7%), cost (149, 31.7%), Physician's choice (39, 8.3%), or other (53, 11.3%). Only 161 (32.8%) of the patients attained their goal LDL-C level. In our modelling analysis, increasing the statin dose to the registered maximum and adding ezetimibe brought an additional 34.5% of patients to goal, while adding a PCSK9-inhibitor, irrespective of any other changes to lipid-lowering therapy brought over 90% of not-at-goal patients to goal. CONCLUSIONS: Most study participants were not at LDL-C goal despite maximum-tolerated statin, highlighting the need for treatment intensification in this high-risk population. Although intensifying treatment by adding a PCSK9-inhibitor brought more patients to goal, the initial addition of ezetimibe would be more reasonable, given the cost of PCSK9-inhibitors.

Management of adult patients with type 1 diabetes mellitus in Africa: A post-hoc cohort analysis of 12 African countries participating in the International Diabetes Management Practices Study (Wave 7).

There is a paucity of information on real world management of African adult patients with type 1 diabetes mellitus (T1DM). We aimed to describe a cohort of African adults with T1DM.The International Diabetes Management Practices Study is an observational survey conducted from 2005 to 2017. Data were collected in seven individual waves from countries in Asia, Africa, East Europe, and Latin America. Wave 7 was conducted from 2016 to 2017 and the African cohort included 12 countries. Questionnaires were administered to clinicians and patients. Analyses were mainly descriptive. Logistic regressions were performed to identify predictive factors for glycaemic control.A total of 788 patients were enrolled in the study. HbA1c values were available for 712 patients; only 16.6% had HbA1c values <7%. A total of 196 (24.9%) reported being hospitalized in the preceding year, with the most common reasons being diabetic ketoacidosis (58.1%, 93/160) and hypoglycaemia (31.1%; 52/167). Over half of the patients (55.4%) stated that the cost of test strips limited regular glycemic monitoring; a minority of patients (15%, 120/788) received structured diabetes education. Predictors of HbA1c <7% included patients receiving diabetes education (odds ratio [OR] [95% confidence interval, CI] = 2.707 [1.157-6.335] P = .022), following a healthy diet and exercise plan (OR [95% CI] = 2.253 [1.206-4.209], P < .001) and self-managing (monitoring glucose levels and adjusting insulin accordingly) (OR [95% CI] 2.508 [1.500-4.191] P < .001).African adults with T1DM have suboptimal glycemic control with almost one-quarter reporting hospitalization within the preceding year. Most patients felt comfortable with self-adjustment of insulin dose but said that the cost of test strips was the main factor that limited regular monitoring. Reducing direct costs of testing strips and insulin, and improving education will address major challenges within these settings.

PCSK9 Inhibitors: From Nature's Lessons to Clinical Utility.

BACKGROUND: Proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors are a novel class of non-statin lipid lowering therapy that reduce LDL-cholesterol by 50 - 60%. PCSK9 inhibitors decrease LDL-cholesterol by preventing intracellular degradation of LDL receptors; subsequently, a greater number of LDL-receptors are available on the cell surface to extract circulating LDL. OBJECTIVE: To describe the origins of PCSK9 inhibitors and their current use in clinical practice. METHODS: We performed a narrative review of the PCSK9 inhibitor class of drugs. RESULTS: Current data indicate that PCSK9 inhibitors effectively reduce LDL-cholesterol and are well tolerated and safe. PCSK9 inhibitors have also been shown to reduce cardiovascular event rates in patients with stable atherosclerotic cardiovascular disease and in patients with a recent (up to one year) acute coronary syndrome. Given the costs, chronicity of the treatment and the potential budget impact, PCSK9 inhibitors are often limited to patients with the highest absolute risk for major adverse cardiovascular events despite optimal treatment with high-intensity statin and ezetimibe. CONCLUSION: PCSK9 inhibitors have a favorable safety, efficacy and tolerability profile. Postmarketing safety surveillance and real-world studies are needed to further support the long-term safety profile of this class of medicine.

Population Pharmacokinetics of Isoniazid, Pyrazinamide, and Ethambutol in Pregnant South African Women with Tuberculosis and HIV.

Tuberculosis is an important cause of maternal morbidity, but little is known about the effects of pregnancy on antituberculosis drug concentrations. We developed population pharmacokinetic models to describe drug dispositions of isoniazid, pyrazinamide, and ethambutol in pregnant women with tuberculosis and HIV. HIV-positive pregnant women with tuberculosis receiving standard first-line tuberculosis treatment and participating in Tshepiso, a prospective cohort study in Soweto, South Africa, underwent sparse pharmacokinetic sampling at >36 weeks of gestation and 7 weeks postpartum. The effects of pregnancy on the pharmacokinetics of isoniazid, pyrazinamide, and ethambutol were investigated via population pharmacokinetic modeling. Isoniazid, pyrazinamide, and ethambutol concentrations were available for 29, 18, and 18 women, respectively. Their median weight was 66 kg while pregnant and 64 kg postpartum. No significant differences were observed in drug clearance, volume of distribution, or bioavailability during and after pregnancy. The model-estimated isoniazid, pyrazinamide, and ethambutol area under the concentration-time curve from 0 to 24 h (AUC0-24) medians were, respectively, 6.88, 419, and 16.5 mg · h/liter during pregnancy versus 5.01, 407, and 19.0 mg · h/liter postpartum. The model-estimated maximum concentration (Cmax) medians for isoniazid, pyrazinamide, and ethambutol were, respectively, 1.39, 35.9, and 1.82 mg/liter during pregnancy versus 1.43, 34.5, and 2.11 mg/liter postpartum. A posteriori power calculations determined that our analysis was powered 91.8%, 59.2%, and 90.1% at a P of <0.01 to detect a 40% decrease in the AUCs of isoniazid, pyrazinamide, and ethambutol, respectively. Pregnancy does not appear to cause relevant changes in the exposure to isoniazid, pyrazinamide, and ethambutol. Additional studies of antituberculosis drugs in pregnancy are needed.

Safety and Efficacy of Enoxaparin in Pregnancy: A Systematic Review and Meta-Analysis.

INTRODUCTION: International guidelines support the use of low molecular weight heparins for the treatment of thromboembolism and thromboprophylaxis during pregnancy. However, evidence of the benefit and harm associated with specific low molecular weight heparins such as enoxaparin is dated. No current systematic review and meta-analysis describing the safety and efficacy of enoxaparin for thromboembolism and thromboprophylaxis during pregnancy exists. METHODS: PubMed, Embase, and Cochrane databases were searched on August 17, 2018 for clinical trials or observational studies in pregnant women receiving enoxaparin; patients with a prosthetic heart valve were excluded. Risk ratios (RR) with 95% confidence intervals (CI) were calculated using a random effects model, and heterogeneity was measured using the I2 statistic. RESULTS: Of the 485 records identified in the search, 24 studies published clinical trials, and observational studies were found dating back to 2000. Only one observational cohort and one randomized control trial focused on the use of enoxaparin for thromboprophylaxis and therefore efficacy was not assessed; the other studies included women with recurrent pregnancy loss (15 studies), history of placental vascular complications (five studies), and recurrent in vitro fertilization failure (two studies) and were therefore analyzed in terms of safety only. Bleeding events were non-significantly more often reported for enoxaparin compared to untreated controls (RR 1.35 [0.88-2.07]) but less often reported for enoxaparin versus aspirin (RR 0.93 [0.62-1.39]); thromboembolic events, thrombocytopenia, and teratogenicity were rarely reported events; in patients with a history of recurrent pregnancy loss, encouragingly the rates of pregnancy loss were significantly lower for enoxaparin compared to untreated controls (RR 0.58 [0.34-0.96]) and enoxaparin + aspirin versus aspirin alone (RR 0.42 [0.32-0.56]) as well as observably lower for enoxaparin versus aspirin alone (RR 0.39 [0.15-1.01]), though significant heterogeneity was observed (I2 > 60). CONCLUSION: Literature on the efficacy and safety of enoxaparin for thromboembolism and thromboprophylaxis remains scanty, and therefore efficacy was not assessed; in terms of safety, when including other indications for enoxaparin in pregnancy, we found that enoxaparin was associated with significantly lower complications than aspirin. Given differences in study design and study heterogeneity, pregnancy loss results should be interpreted with caution. Moreover, reports of thromboembolic events, thrombocytopenia, and congenital malformations were rare. FUNDING: Sanofi.

The effect of food on the pharmacokinetics of oral ivermectin.

BACKGROUND: Ivermectin is an older anthelminthic agent that is being studied more intensely given its potential for mass drug administration against scabies, malaria and other neglected tropical diseases. Its pharmacokinetics (PK) remain poorly characterized. Furthermore, the majority of PK trials are performed under fasted-state dosing conditions, and the effect of food is therefore not well known. To better plan and design field trials with ivermectin, a model that can account for both conditions would be valuable. OBJECTIVES: To develop a PK model and characterize the food effect with single oral doses of ivermectin. PATIENTS AND METHODS: We performed a population-based PK analysis of data pooled from two previous trials of a single dose of 12 mg ivermectin, one with dosing after a high-fat breakfast (n=12) and one with fasted-state dosing (n=3). RESULTS: The final model described concentration-time profiles after fed and fasted dosing accurately, and estimated the food effect associated with relative bioavailability to 1.18 (95% CI 1.10-1.67). CONCLUSIONS: In this analysis, the effect of a high-fat breakfast compared with a fasted-state administration of a single oral dose of 12 mg ivermectin was minimal.

A Clinical Prediction Rule for Protease Inhibitor Resistance in Patients Failing Second-Line Antiretroviral Therapy.

BACKGROUND: Most adults with virological failure on second-line antiretroviral therapy (ART) in resource-limited settings have no major protease inhibitor (PI) resistance mutations. Therefore, empiric switches to third-line ART would waste resources. Genotypic antiretroviral resistance testing (GART) is expensive and has limited availability. A clinical prediction rule (CPR) for PI resistance could rationalize access to GART. SETTING: A private sector ART cohort, South Africa. METHODS: We identified adults with virologic failure on ritonavir-boosted lopinavir/atazanavir-based ART and GART. We constructed a multivariate logistic regression model including age, sex, PI duration, short-term adherence (using pharmacy claims), concomitant CYP3A4-inducing drugs, and viral load at time of GART. We selected variables for the CPR using a stepwise approach and internally validated the model by bootstrapping. RESULTS: 148/339 (44%) patients had PI resistance (defined as ≥ 1 major resistance mutation to current PI). The median age was 42 years (interquartile range 36-48), 212 (63%) were females, 308 (91%) were on lopinavir/ritonavir, and median PI duration was 2.6 years (interquartile range 1.6-4.7). Variables associated with PI resistance and included in the CPR were age {adjusted odds ratio (aOR) 1.96 (95% confidence interval [CI]: 1.42 to 2.70) for 10-year increase}, PI duration (aOR 1.14 [95% CI: 1.03 to 1.26] per year), and adherence (aOR 1.22 [95% CI: 1.12 to 1.33] per 10% increase). The CPR model had a c-statistic of 0.738 (95% CI: 0.686 to 0.791). CONCLUSIONS: Older patients with high adherence and prolonged PI exposure are most likely to benefit from GART to guide selection of a third-line ART regimen. Our CPR to select patients for GART requires external validation before implementation.

Comparison of six methods to estimate adherence in an ART-naïve cohort in a resource-poor setting: which best predicts virological and resistance outcomes?

BACKGROUND: Incomplete adherence to antiretroviral therapy (ART) results in virologic failure and resistance. It remains unclear which adherence measure best predicts these outcomes. We compared six patient-reported and objective adherence measures in one ART-naïve cohort in South Africa. METHODS: We recruited 230 participants from a community ART clinic and prospectively collected demographic data, CD4 count and HIV-RNA at weeks 0, 16 and 48. We quantified adherence using 3-day self-report (SR), clinic-based pill count (CPC), average adherence by pharmacy refill (PR-average), calculation of medication-free days (PR-gaps), efavirenz therapeutic drug monitoring (TDM) and an electronic adherence monitoring device (EAMD). Associations between adherence measures and virologic and genotypic outcomes were modelled using logistic regression, with the area under the curve (AUC) from the receiver operator characteristic (ROC) analyses derived to assess performance of adherence measures in predicting outcomes. RESULTS: At week 48 median (IQR) adherence was: SR 100% (100-100), CPC 100% (95-107), PR-average 103% (95-105), PR-gaps 100% (95-100) and EAMD 86% (59-94), and efavirenz concentrations were therapeutic (>1 mg/L) in 92%. EAMD, PR-average, PR-gaps and CPC best predicted virological outcome at week 48 with AUC ROC of 0.73 (95% CI 0.61-0.83), 0.73 (95% CI 0.61-0.85), 0.72 (95% CI 0.59-0.84) and 0.64 (95% CI 0.52-0.76) respectively. EAMD, PR-gaps and PR-average were highly predictive of detection of resistance mutations at week 48, with AUC ROC of 0.92 (95% CI 0.87-0.97), 0.86 (0.67-1.0) and 0.83 (95% CI 0.65-1.0) respectively. SR and TDM were poorly predictive of outcomes at week 48. CONCLUSION: EAMD and both PR measures predicted resistance and virological failure similarly. Pharmacy refill data is a pragmatic adherence measure in resource-limited settings where electronic monitoring is unavailable. Trial registration The trial was retrospectively registered in the Pan African Clinical Trials Registry, number PACTR201311000641402, on the 13 Sep 2013 ( www.pactr.org ). The first participant was enrolled on the 12th July 2012. The last patient last visit (week 48) was 15 April 2014.

Risk Factors for Incident Diabetes in a Cohort Taking First-Line Nonnucleoside Reverse Transcriptase Inhibitor-Based Antiretroviral Therapy.

Efavirenz is the preferred nonnucleoside reverse transcriptase inhibitor (NNRTI) in first-line antiretroviral therapy (ART) regimens in low- and middle-income countries, where the prevalence of diabetes is increasing. Randomized control trials have shown mild increases in plasma glucose in participants in the efavirenz arms, but no association has been reported with overt diabetes. We explored the association between efavirenz exposure and incident diabetes in a large Southern African cohort commencing NNRTI-based first-line ART. Our cohort included HIV-infected adults starting NNRTI-based ART in a private sector HIV disease management program from January 2002 to December 2011. Incident diabetes was identified by the initiation of diabetes treatment. Patients with prevalent diabetes were excluded. We included 56,298 patients with 113,297 patient-years of follow-up (PYFU) on first-line ART. The crude incidence of diabetes was 13.24 per 1000 PYFU. Treatment with efavirenz rather than nevirapine was associated with increased risk of developing diabetes (hazard ratio 1.27 (95% confidence interval (CI): 1.10-1.46)) in a multivariate analysis adjusting for age, sex, body mass index, baseline CD4 count, viral load, NRTI backbone, and exposure to other diabetogenic medicines. Zidovudine and stavudine exposure were also associated with an increased risk of developing diabetes. We found that treatment with efavirenz, as well as stavudine and zidovudine, increased the risk of incident diabetes. Interventions to detect and prevent diabetes should be implemented in ART programs, and use of antiretrovirals with lower risk of metabolic complications should be encouraged.

Third-line antiretroviral therapy in Africa: effectiveness in a Southern African retrospective cohort study.

BACKGROUND: An increasing number of patients in Africa are experiencing virologic failure on second-line antiretroviral therapy (ART) and those who develop resistance to protease inhibitors (PI) will require third-line ART, but no data on the outcomes of third-line are available from the region. We assessed the virologic outcomes and survival of patients started on salvage ART in a Southern African private sector disease management programme. METHODS: Retrospective observational cohort study with linkage to the national death register. Adults (≥18 years) who started salvage ART between July 2007 and December 2011 were included. Salvage ART was defined by inclusion of darunavir or tipranavir in an ART regimen after having failed another PI. For Kaplan-Meier (KM) analysis, patients were followed up until event, or censored at death (only for virologic outcomes), leaving the programme, or April 2014. RESULTS: 152 patients were included. Subtype was known for 113 patients: 111 (98 %) were infected with subtype C. All 152 had a genotype resistance test demonstrating major PI resistance mutations. Salvage drugs included were: darunavir/ritonavir (n = 149), tipranavir/ritonavir (n = 3), raltegravir (n = 58), and etravirine (n = 8). Median follow-up was 2.5 years (IQR = 1.5-3.3). 82.9 % achieved a viral load ≤400 copies/ml and 71.1 % ≤50 copies/ml. By the end of the study 17 (11.2 %) of the patients had died. The KM estimate of cumulative survival was 87.2 % at 2000 days. CONCLUSIONS: Virologic suppression was comparable to that demonstrated in clinical trials and observational studies of salvage ART drugs conducted in other regions. Few deaths occurred during short term follow-up. Third-line regimens for patients with multidrug resistant subtype C HIV in Africa are virologically and clinically effective.

Short term adherence tool predicts failure on second line protease inhibitor-based antiretroviral therapy: an observational cohort study.

BACKGROUND: Most patients who experience virologic failure (VF) on second line antiretroviral therapy (ART) in low-middle income countries fail due to poor adherence rather than antiretroviral resistance. A simple adherence tool designed to detect VF would conserve resources by rationally limiting need for viral load (VL) testing and, in those countries with access to third line ART, the need for resistance testing. METHODS: We conducted an observational cohort study of patients who initiated second line ART at a clinic in Kwazulu-Natal, South Africa. Using clinical and pharmacy refill data extracted from the clinic's electronic database, we determined risk factors for VF. Three different methods of calculating short term pharmacy refill adherence were evaluated and compared with long term adherence since second line initiation. We also explored the ability of differing durations of short term pharmacy refill to predict VF on second line ART. RESULTS: We included 274 patients with a median follow up of 27 months on second line ART. VF ranged between 3% and 16% within each six month interval after initiating second line ART. 243 patients with at least one VL after 4 months on second line were analysed in the statistical analysis. Pharmacy refill adherence assessed over shorter periods (4 to 6 months) predicted virologic suppression as well as pharmacy refill assessed over longer periods. The risk of VF fell 73% with each 10% increase in adherence measured from pharmacy refills over a 4 month period. Low CD4 count at second line ART initiation was a significant independent risk factor for VF. CONCLUSION: Patients identified as poorly adherent by short term pharmacy refill are at risk for VF on second line ART. This pragmatic adherence tool could assist in identifying patients who require adherence interventions, and help rationalize use of VL monitoring and resistance testing among patients on second line ART.

A novel Markov model projecting costs and outcomes of providing antiretroviral therapy to public patients in private practices versus public clinics in South Africa.

INTRODUCTION: Providing private antiretroviral therapy (ART) care for public sector patients could increase access to ART in low- and middle-income countries. We compared the costs and outcomes of a private-care and a public-care ART program in South Africa. METHODS: A novel Markov model was developed from the public-care program. Patients were first tunneled for 6 months in their baseline CD4 category before being distributed into a dynamic CD4 and viral load model. Patients were allowed to return to ART care from loss to follow up (LTFU). We then populated this modeling framework with estimates derived from the private-care program to externally validate the model. RESULTS: Baseline characteristics were similar in the two programs. Clinic visit utilization was higher and death rates were lower in the first few years on ART in the public-care program. After 10 years on ART we estimated the following outcomes in the public-care and private-care programs respectively: viral load <1000 copies/ml 89% and 84%, CD4 >500 cells/µl 33% and 37%, LTFU 14% and 14%, and death 27% and 32%. Lifetime undiscounted survival estimates were 14.1 (95%CI 13.2-14.9) and (95%CI 12.7-14.5) years with costs of 18,734 (95%CI 12,588-14,022) and 13,062 (95%CI 12,077-14,047) USD in the private-care and public-care programs respectively. When clinic visit utilization in the public-care program was reduced by two thirds after the initial 6 months on ART, which is similar to their current practice, the costs were comparable between the programs. CONCLUSIONS: Using a novel Markov model, we determined that the private-care program had similar outcomes but lower costs than the public-care program, largely due to lower visit frequencies. These findings have important implications for increasing and sustaining coverage of patients in need of ART care in resource-limited settings.