Portia Kamthunzi

Antiretroviral treatment for children with peripartum nevirapine exposure

BACKGROUND Single-dose nevirapine is the cornerstone of the regimen for prevention of mother-to-child transmission of human immunodeficiency virus (HIV) in resource-limited settings, but nevirapine frequently selects for resistant virus in mothers and children who become infected despite prophylaxis. The optimal antiretroviral treatment strategy for children who have had prior exposure to single-dose nevirapine is unknown. METHODS We conducted a randomized trial of initial therapy with zidovudine and lamivudine plus either nevirapine or ritonavir-boosted lopinavir in HIV-infected children 6 to 36 months of age, in six African countries, who qualified for treatment according to World Health Organization (WHO) criteria. Results are reported for the cohort that included children exposed to single-dose nevirapine prophylaxis. The primary end point was virologic failure or discontinuation of treatment by study week 24. Enrollment in this cohort was terminated early on the recommendation of the data and safety monitoring board. RESULTS A total of 164 children were enrolled. The median percentage of CD4+ lymphocytes was 19%; a total of 56% of the children had WHO stage 3 or 4 disease. More children in the nevirapine group than in the ritonavir-boosted lopinavir group reached a primary end point (39.6% vs. 21.7%; weighted difference, 18.6 percentage-points; 95% confidence interval, 3.7 to 33.6; nominal P=0.02). Baseline resistance to nevirapine was detected in 18 of 148 children (12%) and was predictive of treatment failure. No significant between-group differences were seen in the rate of adverse events. CONCLUSIONS Among children with prior exposure to single-dose nevirapine for perinatal prevention of HIV transmission, antiretroviral treatment consisting of zidovudine and lamivudine plus ritonavir-boosted lopinavir resulted in better outcomes than did treatment with zidovudine and lamivudine plus nevirapine. Since nevirapine is used for both treatment and perinatal prevention of HIV infection in resource-limited settings, alternative strategies for the prevention of HIV transmission from mother to child, as well as for the treatment of HIV infection, are urgently required. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00307151.).

Nevirapine versus Ritonavir-Boosted Lopinavir for HIV-Infected Children

BACKGROUND Nevirapine-based antiretroviral therapy is the predominant (and often the only) regimen available for children in resource-limited settings. Nevirapine resistance after exposure to the drug for prevention of maternal-to-child human immunodeficiency virus (HIV) transmission is common, a problem that has led to the recommendation of ritonavir-boosted lopinavir in such settings. Regardless of whether there has been prior exposure to nevirapine, the performance of nevirapine versus ritonavir-boosted lopinavir in young children has not been rigorously established. METHODS In a randomized trial conducted in six African countries and India, we compared the initiation of HIV treatment with zidovudine, lamivudine, and either nevirapine or ritonavir-boosted lopinavir in HIV-infected children 2 to 36 months of age who had no prior exposure to nevirapine. The primary end point was virologic failure or discontinuation of treatment by study week 24. RESULTS A total of 288 children were enrolled; the median percentage of CD4+ T cells was 15%, and the median plasma HIV type 1 (HIV-1) RNA level was 5.7 log(10) copies per milliliter. The percentage of children who reached the primary end point was significantly higher in the nevirapine group than in the ritonavir-boosted lopinavir group (40.8% vs. 19.3%; P<0.001). Among the nevirapine-treated children with virologic failure for whom data on resistance were available, more than half (19 of 32) had resistance at the time of virologic failure. In addition, the time to a protocol-defined toxicity end point was shorter in the nevirapine group (P=0.04), as was the time to death (P=0.06). CONCLUSIONS Outcomes were superior with ritonavir-boosted lopinavir among young children with no prior exposure to nevirapine. Factors that may have contributed to the suboptimal results with nevirapine include elevated viral load at baseline, selection for nevirapine resistance, background regimen of nucleoside reverse-transcriptase inhibitors, and the standard ramp-up dosing strategy. The results of this trial present policymakers with difficult choices. (Funded by the National Institute of Allergy and Infectious Diseases and others; P1060 ClinicalTrials.gov number, NCT00307151.).

Genetic diversity and protective efficacy of the RTS,S/AS01 malaria vaccine

BACKGROUND The RTS,S/AS01 vaccine targets the circumsporozoite protein of Plasmodium falciparum and has partial protective efficacy against clinical and severe malaria disease in infants and children. We investigated whether the vaccine efficacy was specific to certain parasite genotypes at the circumsporozoite protein locus. METHODS We used polymerase chain reaction-based next-generation sequencing of DNA extracted from samples from 4985 participants to survey circumsporozoite protein polymorphisms. We evaluated the effect that polymorphic positions and haplotypic regions within the circumsporozoite protein had on vaccine efficacy against first episodes of clinical malaria within 1 year after vaccination. RESULTS In the per-protocol group of 4577 RTS,S/AS01-vaccinated participants and 2335 control-vaccinated participants who were 5 to 17 months of age, the 1-year cumulative vaccine efficacy was 50.3% (95% confidence interval [CI], 34.6 to 62.3) against clinical malaria in which parasites matched the vaccine in the entire circumsporozoite protein C-terminal (139 infections), as compared with 33.4% (95% CI, 29.3 to 37.2) against mismatched malaria (1951 infections) (P=0.04 for differential vaccine efficacy). The vaccine efficacy based on the hazard ratio was 62.7% (95% CI, 51.6 to 71.3) against matched infections versus 54.2% (95% CI, 49.9 to 58.1) against mismatched infections (P=0.06). In the group of infants 6 to 12 weeks of age, there was no evidence of differential allele-specific vaccine efficacy. CONCLUSIONS These results suggest that among children 5 to 17 months of age, the RTS,S vaccine has greater activity against malaria parasites with the matched circumsporozoite protein allele than against mismatched malaria. The overall vaccine efficacy in this age category will depend on the proportion of matched alleles in the local parasite population; in this trial, less than 10% of parasites had matched alleles. (Funded by the National Institutes of Health and others.).

Assessment of severe malaria in a multicenter, phase III, RTS, S/AS01 malaria candidate vaccine trial: case definition, standardization of data collection and patient care

BackgroundAn effective malaria vaccine, deployed in conjunction with other malaria interventions, is likely to substantially reduce the malaria burden. Efficacy against severe malaria will be a key driver for decisions on implementation. An initial study of an RTS, S vaccine candidate showed promising efficacy against severe malaria in children in Mozambique. Further evidence of its protective efficacy will be gained in a pivotal, multi-centre, phase III study. This paper describes the case definitions of severe malaria used in this study and the programme for standardized assessment of severe malaria according to the case definition.MethodsCase definitions of severe malaria were developed from a literature review and a consensus meeting of expert consultants and the RTS, S Clinical Trial Partnership Committee, in collaboration with the World Health Organization and the Malaria Clinical Trials Alliance. The same groups, with input from an Independent Data Monitoring Committee, developed and implemented a programme for standardized data collection.The case definitions developed reflect the typical presentations of severe malaria in African hospitals. Markers of disease severity were chosen on the basis of their association with poor outcome, occurrence in a significant proportion of cases and on an ability to standardize their measurement across research centres. For the primary case definition, one or more clinical and/or laboratory markers of disease severity have to be present, four major co-morbidities (pneumonia, meningitis, bacteraemia or gastroenteritis with severe dehydration) are excluded, and a Plasmodium falciparum parasite density threshold is introduced, in order to maximize the specificity of the case definition. Secondary case definitions allow inclusion of co-morbidities and/or allow for the presence of parasitaemia at any density. The programmatic implementation of standardized case assessment included a clinical algorithm for evaluating seriously sick children, improvements to care delivery and a robust training and evaluation programme for clinicians.ConclusionsThe case definition developed for the pivotal phase III RTS, S vaccine study is consistent with WHO recommendations, is locally applicable and appropriately balances sensitivity and specificity in the diagnosis of severe malaria. Processes set up to standardize severe malaria data collection will allow robust assessment of the efficacy of the RTS, S vaccine against severe malaria, strengthen local capacity and benefit patient care for subjects in the trial.Trial registrationClinicaltrials.gov NCT00866619

Effect of provider-initiated testing and counselling and integration of ART services on access to HIV diagnosis and treatment for children in Lilongwe Malawi: a pre- post comparison.

BackgroundThe HIV prevalence in Malawi is 12% and Kamuzu Central Hospital (KCH), in the capital Lilongwe, is the main provider of adult and paediatric HIV services in the central region. The Lighthouse at KCH offers opt-in HIV testing and counselling (HTC) for adults and children. In June 2004, Lighthouse was the first clinic to provide free antiretroviral treatment (ART) in the public sector, but few children accessed the services. In response, provider-initiated HIV testing and counselling (PITC) and an ART clinic were introduced at the paediatric department at KCH in Quarter 4 (Q4) 2004.MethodsWe analysed prospectively collected, aggregated data of quarterly reports from Q1 2003 to Q4 2006 from HTC centre registers, ART registers and clinic registrations at the ART clinics of both Lighthouse and the paediatric department. By comparing data of both facilities before (Q1 2003 to Q3 2004), and after the introduction of the services at the paediatric department (Q4 2004 to Q4 2006), we assessed the effect of this intervention on the uptake of HIV services for children at KCH.ResultsOverall, 3971 children were tested for HIV, 2428 HIV-infected children were registered for care and 1218 started ART. Between the two periods, the median (IQR) number of children being tested, registered and starting ART per quarter rose from 101 (53-109) to 358 (318-440), 56 (50-82) to 226 (192-234) and 18 (8-23) to 139 (115-150), respectively. The median proportion of tested clients per quarter that were children rose from 3.8% (2.7-4.3) to 9.6% (8.8 to 10.0) (p = 0.0009) and the proportion of ART starters that were children rose from 6.9% (4.9-9.3) to 21.1% (19.2-24.2) (p = 0.0036). The proportion of registered children and adults starting ART each quarter increased similarly, from 26% to 53%, and 20% to 52%, respectively.ConclusionsImplementation of PITC and integration of ART services within the paediatric ward are likely to be the main reasons for improved access to HTC and ART for children at KCH, and can be recommended to other hospitals with paediatric inpatients in resource limited settings with high HIV prevalence.

Determining the quality of IMCI pneumonia care in Malawian children

Abstract Background: Although pneumonia is the leading cause of child mortality worldwide, little is known about the quality of routine pneumonia care in high burden settings like Malawi that utilize World Health Organizations Integrated Management of Childhood Illnesses (IMCI) guidelines. Due to severe human resource constraints, the majority of clinical care in Malawi is delivered by non-physician clinicians called Clinical Officers (COs). Aim: To assess the quality of child pneumonia care delivered by Malawian COs in routine care conditions. Methods: At an outpatient district-level clinic in Lilongwe, Malawi, 10 COs caring for 695 children who presented with fever, cough, or difficulty breathing were compared to IMCI pneumonia diagnostic and treatment guidelines. Results: Fewer than 1% of patients received an evaluation by COs that included all 16 elements of the history and physical examination. The respiratory rate was only determined in 16·1% of patients presenting with cough or difficulty breathing. Of the 274 children with IMCI-defined pneumonia, COs correctly diagnosed 30%, and administered correct pneumonia care in less than 25%. COs failed to hospitalize 40·8% of children with severe or very severe pneumonia. Conclusions: IMCI pneumonia care quality at this Malawian government clinic is alarmingly low. Along with reassessing current pneumonia training and supervision approaches, novel quality improvement interventions are necessary to improve care.

Nevirapine- Versus Lopinavir/Ritonavir-Based Antiretroviral Therapy in HIV-Infected Infants and Young Children: Long-term Follow-up of the IMPAACT P1060 Randomized Trial

BACKGROUND The International Maternal Pediatric Adolescent AIDS Clinical Trials Network (IMPAACT) P1060 study demonstrated short-term superiority of lopinavir/ritonavir (LPV/r) over nevirapine (NVP) in antiretroviral therapy (ART), regardless of prior NVP exposure. However, NVP-based ART had a marginal benefit in CD4 percentage (CD4%) and growth. We compared 5-year outcomes from this clinical trial. METHODS Human immunodeficiency virus (HIV)-infected, ART-eligible children were enrolled into 2 cohorts based on prior NVP exposure and randomized to NVP- or LPV/r-based ART. The data safety monitoring board recommended unblinding results in both cohorts due to superiority of LPV/r for the primary endpoint: stopping randomized treatment, virologic failure (VF), or death by 6 months. Participants were offered a switch in regimens (if on NVP) and continued observational follow-up. We compared time to VF or death, death, and CD4% and growth changes using intention-to-treat analyses. Additionally, inverse probability weights were used to account for treatment switching and censoring. RESULTS As of September 2014, 329 of the 451 (73%) enrolled participants were still in follow-up (median, 5.3 years; interquartile range [IQR], 4.3-6.4), with 52% on NVP and 88% on LPV/r as originally randomized. NVP arm participants had significantly higher risk of VF or death (adjusted hazard ratio [aHR], 1.90; 95% confidence interval [CI], 1.37-2.65) but not death alone (aHR, 1.65; 95% CI, .72-3.76) compared with participants randomized to LPV/r. Mean CD4% was significantly higher in the NVP arm up to 1 year after ART initiation, but not beyond. Mean weight-for-age z scores were marginally higher in the NVP arm, but height-for-age z scores did not differ. Similar trends were observed in sensitivity analyses. CONCLUSIONS These findings support the current World Health Organization recommendation of LPV/r in first-line ART regimens for HIV-infected children. CLINICAL TRIALS REGISTRATION NCT00307151.

Predictors of virologic and clinical response to nevirapine versus lopinavir/ritonavir-based antiretroviral therapy in young children with and without prior nevirapine exposure for the prevention of mother-to-child HIV transmission

Background: In a randomized trial comparing nevirapine (NVP)-based versus lopinavir/ritonavir (LPV/r)-based antiretroviral therapy (ART) in HIV-infected children [primary endpoint discontinuation of study treatment for any reason or virologic failure by week 24] aged 2 months to 3 years, we assessed whether clinical, virologic, immunologic and safety outcomes varied by prior single-dose NVP exposure (PrNVP) for prevention of mother-to-child HIV transmission and other covariates. Methods: Efficacy was assessed by time to ART discontinuation or virologic failure, virologic failure/death and death; safety by time to ART discontinuation because of a protocol-defined toxicity and first ≥ grade 3 adverse event; immunology and growth by changes in CD4%, weight/height World Health Organization z-scores from entry to week 48. Cox proportional hazards and linear regression models were used to test whether treatment differences depended on PrNVP exposure and other covariates. Results: Over a median follow up of 48 (PrNVP) and 72 (no PrNVP) weeks, there was no evidence of differential treatment effects by PrNVP exposure or any other covariates. LPV/r-based ART was superior to NVP-based ART for efficacy and safety outcomes; however, those on NVP had larger improvements in CD4%, weight and height z-scores. Lower pretreatment CD4% and higher HIV-1 RNA levels were associated with reduced efficacy, lower pretreatment CD4% with shorter time to ART discontinuation because of a protocol-defined toxicity, and no PrNVP with shorter time to first grade ≥3 adverse event. Conclusions: Differences between LPV/r and NVP ART in efficacy, safety, immunologic and growth outcomes did not depend on PrNVP exposure, prior breast-feeding, sex, HIV-1 subtype, age, pretreatment CD4%, HIV-1 RNA or World Health Organization disease stage. This finding should be considered when selecting an ART regimen for young children.

Estimation of Plasmodium falciparum Transmission Intensity in Lilongwe, Malawi, by Microscopy, Rapid Diagnostic Testing, and Nucleic Acid Detection

Estimates of malaria transmission intensity (MTI) typically rely upon microscopy or rapid diagnostic testing (RDT). However, these methods are less sensitive than nucleic acid amplification techniques and may underestimate parasite prevalence. We compared microscopy, RDT, and polymerase chain reaction (PCR) for the diagnosis of Plasmodium falciparum parasitemia as part of an MTI study of 800 children and adults conducted in Lilongwe, Malawi. PCR detected more cases of parasitemia than microscopy or RDT. Age less than 5 years predicted parasitemia detected by PCR alone (adjusted odds ratio = 1.61, 95% confidence interval = 1.09-2.38, Wald P = 0.02). In addition, we identified one P. falciparum parasite with a false-negative RDT result due to a suspected deletion of the histidine-rich protein 2 (hrp2) gene and used a novel, ultrasensitive PCR assay to detect low-level parasitemia missed by traditional PCR. Molecular methods should be considered for use in future transmission studies as a supplement to RDT or microscopy.

Neuropsychological performance in African children with HIV enrolled in a multisite antiretroviral clinical trial

Objective and design: Children with HIV infection (HIV+) are at neuropsychological risk, but few studies have evaluated this at multiple sites in low-income and middle-income countries. We compared neuropsychological outcomes at enrollment (>5 years age) among HIV+, HIV perinatally exposed uninfected (HEU), and HIV unexposed uninfected (HUU) children from four sub-Saharan countries. Methods: IMPAACT P1060 compared nevirapine versus lopinavir/ritonavir-based antiretroviral treatment (ART) in HIV-infected children 6–35 months of age. The present study (P1104s) enrolled P1060 children at 5–11 years of age and evaluated their neuropsychological performance over 2 years using the Kaufman Assessment Battery for Children, 2nd edition (KABC-II), Tests of Variables of Attention (TOVA), Bruininks–Oseretsky Test, 2nd edition (BOT-2), and parent-reported Behavior Rating Inventory of Executive Function (BRIEF). Cohorts were compared using generalized estimating equations least-squares means adjusted for site, child age and sex, and personal and social characteristics for child and caregiver. Results: Six hundred and eleven (246 HIV+, 183 HEU, 182 HUU) of the 615 enrolled at six sites [South Africa (three), Zimbabwe, Malawi, Uganda] were available for analysis. Mean age was 7.2 years, 48% male, 69% in school. Unadjusted and adjusted comparisons were consistent. HIV+ children performed significantly worse than HEU and HUU cohorts on all KABC-II cognitive performance domains and on BOT-2 total motor proficiency (P < 0.001), but not on the BRIEF Global Executive Indices. HUU and HEU cohorts were comparable on cognitive outcomes. HIV+ children initiated on ART before 1 year of age had significantly better BRIEF evaluations (lower scores - fewer behavior problems), compared with those started after (P = 0.03). Conclusion: Significant cognitive deficits were documented among HIV+ children at school age, even when started on ART at an early age. Earlier HIV treatment, neuropsychological monitoring, and rehabilitative interventions are all needed. Subsequent testing for 2 more years will help further evaluate how HIV infection and exposure affect the developmental trajectory.