Overcoming roadblocks in the development of vaccines for leishmaniasis.

INTRODUCTION: The leishmaniases represent a group of parasitic diseases caused by infection with one of several species of Leishmania parasites. Disease presentation varies because of differences in parasite and host genetics and may be influenced by additional factors such as host nutritional status or co-infection. Studies in experimental models of Leishmania infection, vaccination of companion animals and human epidemiological data suggest that many forms of leishmaniasis could be prevented by vaccination, but no vaccines are currently available for human use. AREAS COVERED: We describe some of the existing roadblocks to the development and implementation of an effective leishmaniasis vaccine, based on a review of recent literature found on PubMed, BioRxiv and MedRxiv. In addition to discussing scientific unknowns that hinder vaccine candidate identification and selection, we explore gaps in knowledge regarding the commercial and public health value propositions underpinning vaccine development and provide a route map for future research and advocacy. EXPERT OPINION: Despite significant progress, leishmaniasis vaccine development remains hindered by significant gaps in understanding that span the vaccine development pipeline. Increased coordination and adoption of a more holistic view to vaccine development will be required to ensure more rapid progress in the years ahead.

Economic evaluation of weekends-off antiretroviral therapy for young people in 11 countries.

OBJECTIVES: To analyze the cost effectiveness of short-cycle therapy (SCT), where patients take antiretroviral (ARV) drugs 5 consecutive days a week and have 2 days off, as an alternative to continuous ARV therapy for young people infected with human immunodeficiency virus (HIV) and taking efavirenz-based first-line ARV drugs. METHODS: We conduct a hierarchical cost-effectiveness analysis based on data on clinical outcomes and resource use from the BREATHER trial. BREATHER is a randomized trial investigating the effectiveness of SCT and continuous therapy in 199 participants aged 8 to 24 years and taking efavirenz-based first-line ARV drugs in 11 countries worldwide. Alongside nationally representative unit costs/prices, these data were used to estimate costs and quality adjusted life years (QALYs). An incremental cost-effectiveness comparison was performed using a multilevel bivariate regression approach for total costs and QALYs. Further analyses explored cost-effectiveness in low- and middle-income countries with access to low-cost generic ARV drugs and high-income countries purchasing branded ARV drugs, respectively. RESULTS: At 48 weeks, SCT offered significant total cost savings over continuous therapy of US dollar (USD) 41 per patient in countries using generic drugs and USD 4346 per patient in countries using branded ARV drugs, while accruing nonsignificant total health benefits of 0.008 and 0.009 QALYs, respectively. Cost-effectiveness estimates were similar across settings with access to generic ARV drugs but showed significant variation among high-income countries where branded ARV drugs are purchased. CONCLUSION: SCT is a cost-effective treatment alternative to continuous therapy for young people infected with HIV in countries where viral load monitoring is available.

Opportunities for improving the efficiency of paediatric HIV treatment programmes.

OBJECTIVES: To conduct two economic analyses addressing whether to: routinely monitor HIV-infected children on antiretroviral therapy (ART) clinically or with laboratory tests; continue or stop cotrimoxazole prophylaxis when children become stabilized on ART. DESIGN AND METHODS: The ARROW randomized trial investigated alternative strategies to deliver paediatric ART and cotrimoxazole prophylaxis in 1206 Ugandan/Zimbabwean children. Incremental cost-effectiveness and value of implementation analyses were undertaken. Scenario analyses investigated whether laboratory monitoring (CD4 tests for efficacy monitoring; haematology/biochemistry for toxicity) could be tailored and targeted to be delivered cost-effectively. Cotrimoxazole use was examined in malaria-endemic and non-endemic settings. RESULTS: Using all trial data, clinical monitoring delivered similar health outcomes to routine laboratory monitoring, but at a reduced cost, so was cost-effective. Continuing cotrimoxazole improved health outcomes at reduced costs. Restricting routine CD4 monitoring to after 52 weeks following ART initiation and removing toxicity testing was associated with an incremental cost-effectiveness ratio of $6084 per quality-adjusted life-year (QALY) across all age groups, but was much lower for older children (12+ years at initiation; incremental cost-effectiveness ratio = $769/QALY). Committing resources to improve cotrimoxazole implementation appears cost-effective. A healthcare system that could pay $600/QALY should be willing to spend up to $12.0 per patient-year to ensure continued provision of cotrimoxazole. CONCLUSION: Clinically driven monitoring of ART is cost-effective in most circumstances. Routine laboratory monitoring is generally not cost-effective at current prices, except possibly CD4 testing amongst adolescents initiating ART. Committing resources to ensure continued provision of cotrimoxazole in health facilities is more likely to represent an efficient use of resources.

Cost-effectiveness of HIV drug resistance testing to inform switching to second line antiretroviral therapy in low income settings.

BACKGROUND: To guide future need for cheap resistance tests for use in low income settings, we assessed cost-effectiveness of drug resistance testing as part of monitoring of people on first line ART - with switching from first to second line ART being conditional on NNRTI drug resistance mutations being identified. METHODS: An individual level simulation model of HIV transmission, progression and the effect of ART which accounts for adherence and resistance development was used to compare outcomes of various potential monitoring strategies in a typical low income setting in sub-Saharan Africa. Underlying monitoring strategies considered were based on clinical disease, CD4 count or viral load. Within each we considered a strategy in which no further measures are performed, one with a viral load measure to confirm failure, and one with both a viral load measure and a resistance test. Predicted outcomes were assessed over 2015-2025 in terms of viral suppression, first line failure, switching to second line regimen, death, HIV incidence, disability-adjusted-life-years averted and costs. Potential future low costs of resistance tests ($30) were used. RESULTS: The most effective strategy, in terms of DALYs averted, was one using viral load monitoring without confirmation. The incremental cost-effectiveness ratio for this strategy was $2113 (the same as that for viral load monitoring with confirmation). ART monitoring strategies which involved resistance testing did not emerge as being more effective or cost effective than strategies not using it. The slightly reduced ART costs resulting from use of resistance testing, due to less use of second line regimens, was of similar magnitude to the costs of resistance tests. CONCLUSION: Use of resistance testing at the time of first line failure as part of the decision whether to switch to second line therapy was not cost-effective, even though the test was assumed to be very inexpensive.

An assessment of the cost-effectiveness of midwife-led care in the United Kingdom.

OBJECTIVES: to analyse the existing evidence on the cost-effectiveness of midwife-led care compared with consultant-led care in settings potentially generalisable to the United Kingdom, and to estimate the potential cost savings accruing from an expansion of midwife-led care in the United Kingdom. DESIGN: a systematic review of the literature was conducted across twelve electronic databases for papers relating to the costs of midwife-led models of care. Randomised controlled trials, controlled clinical trials, controlled before and after studies and interrupted time series studies were considered for inclusion. The methods specified by the National Institute for Health and Clinical Excellence to assess the cost-effectiveness of midwife-led care were broadly used. Multiple simple one-way sensitivity analyses were undertaken to examine the robustness of findings to varying scenarios. FINDINGS: based on scant existing evidence, the mean cost saving for each eligible maternity was estimated at approximately ST£12.38 (sterling). If midwife-led services were expanded to 50% of all eligible women in the UK, as assumed in the main set of results, this would result in an aggregate cost saving of ST£1.16 million per year. In the sensitivity analyses, cost changes per maternity vary from a saving of ST£253.38 to a cost increase of ST£108.12 depending on the assumptions used, corresponding to aggregate savings of ST£23.75 million and a cost increase of ST£10.13 million. KEY CONCLUSIONS: expanding midwife-led maternity services for eligible women may offer a means of reducing costs compared to the current leading model of care. However, firm conclusions are elusive due to the paucity of evidence. IMPLICATIONS FOR PRACTICE: there is a clear need for further economic evaluations of models of maternity care in the United Kingdom context to guide the better use of scarce resources.