"Cheaper and better": Societal cost savings and budget impact of changing from systemic to intralesional pentavalent antimonials as the first-line treatment for cutaneous leishmaniasis in Bolivia

"It's not all about the disease": do treatment and socioeconomic status affect perceived impact and satisfaction of patients treated for cutaneous leishmaniasis?

BACKGROUND

This cross-sectional study compared the general impact of cutaneous leishmaniasis (CL) and patient satisfaction with treatment and health services as perceived by those undergoing different therapeutic regimens in an endemic region in South-Eastern Brazil. We also investigated the factors associated with both outcomes (general impact and satisfaction).

METHODS

We included 84 patients with CL treated between 2018 and 2019 with intravenous meglumine antimoniate, liposomal amphotericin B, or intralesional meglumine antimoniate therapy. Data were collected through interviews that assessed sociodemographic characteristics, comorbidity status, access and use of health services for CL diagnosis and treatment, and the items of the Cutaneous Leishmaniasis Impact Questionnaire (CLIQ). The CLIQ is a psychometric questionnaire previously validated to assess the general impact of CL on patient satisfaction with treatment and health services. Multivariate logistic regression analysis was used to identify the factors associated with high CL impact and low patient satisfaction.

RESULTS

The general impact of CL and patient satisfaction with treatment and health services were not significantly associated with the therapeutic regimen. High CL impact was associated with low family income (odds ratio [OR]:3.3; 95% confidence interval [CI]:1.0-10.3), occurrence of complications/adverse effects during treatment (OR:7.7; 95%CI:2.4-25.6), and additional costs during diagnosis and/or treatment (OR:12.1; 95% CI:2.8-52.4). Low satisfaction was associated with high disease impact (OR: 9.5; 95% CI:2.7-33.9), occurrence of complications/adverse effects (OR:4.2; 95% CI:1.3-13.0), and high family income (OR:7.1; 95%CI:1.7-28.2).

CONCLUSIONS

Our data support public health policies aimed at reducing the impact of CL and its treatment as well as the use of therapy with fewer adverse effects.

Data-driven predictions of potential Leishmania vectors in the Americas

The incidence of vector-borne diseases is rising as deforestation, climate change, and globalization bring humans in contact with arthropods that can transmit pathogens. In particular, incidence of American Cutaneous Leishmaniasis (ACL), a disease caused by parasites transmitted by sandflies, is increasing as previously intact habitats are cleared for agriculture and urban areas, potentially bringing people into contact with vectors and reservoir hosts. Previous evidence has identified dozens of sandfly species that have been infected with and/or transmit Leishmania parasites. However, there is an incomplete understanding of which sandfly species transmit the parasite, complicating efforts to limit disease spread. Here, we apply machine learning models (boosted regression trees) to leverage biological and geographical traits of known sandfly vectors to predict potential vectors. Additionally, we generate trait profiles of confirmed vectors and identify important factors in transmission. Our model performed well with an average out of sample accuracy of 86%. The models predict that synanthropic sandflies living in areas with greater canopy height, less human modification, and within an optimal range of rainfall are more likely to be Leishmania vectors. We also observed that generalist sandflies that are able to inhabit many different ecoregions are more likely to transmit the parasites. Our results suggest that Psychodopygus amazonensis and Nyssomia antunesi are unidentified potential vectors, and should be the focus of sampling and research efforts. Overall, we found that our machine learning approach provides valuable information for Leishmania surveillance and management in an otherwise complex and data sparse system.

[Synthesis of evidence and recommendations: guideline for the treatment of leishmaniasis in the Region of the AmericasSíntese de evidências e recomendações: diretrizes para o tratamento das leishmanioses na Região das Américas]

Introduction

Leishmaniasis continues to be a neglected infectious disease of great importance, mainly affecting the poorest people with the least access to health services. In the Americas, it is a public health problem due to its magnitude, wide geographical distribution, and levels of morbidity and mortality.

Objective

Summarize the recommendations included in Guideline for the Treatment of Leishmaniasis in the Region of the Americas, published by the Pan American Health Organization/World Health Organization, in order to provide adequate management of patients diagnosed with leishmaniasis, reduce clinical complications and deaths caused by drug toxicity, reduce the lethality of visceral leishmaniasis, and address key aspects of implementation of the guidelines.

Methods

The guideline and its recommendations were summarized and a systematic search was carried out in PubMed, Lilacs, Health Systems Evidence, Epistemonikos, and gray literature for other studies conducted in the Region of the Americas, in order to identify barriers, facilitators, and implementation strategies.

Results

Recommendations are presented, addressing the pharmacological treatment of patients diagnosed with cutaneous, mucosal, and visceral leishmaniasis in the Americas, as well as case management and secondary prophylaxis in patients coinfected with visceral leishmaniasis and HIV, and patients with other diseases that cause immunosuppression.

Conclusions

The recommendations aim to provide the government entities and health professionals that care for leishmaniasis patients in the Americas with knowledge on management of the disease. Barriers are discussed (related to human resources, knowledge of guidelines, inputs, costs, access, and patient access), as well as facilitators and strategies to support implementation.

Intralesional Meglumine Antimoniate: Safe, Feasible and Effective Therapy for Cutaneous Leishmaniasis in Bolivia

The standard of care for cutaneous leishmaniasis includes the intramuscular/intravenous administration of pentavalent antimonials that are toxic and poorly tolerated. Primary health care usually lacks trained health staff for the diagnosis and treatment of leishmaniasis in Cochabamba Bolivia. Taking these aspects into account, a Bolivian consortium set out to explore the intralesional administration of meglumine antimoniate to treat cutaneous leishmaniasis during primary care under programmatic conditions. A four-step strategy consisting of clinical training for intralesional treatment and the promotion and periodic follow-up of health staff was carried out. The training process was applied in situ to personnel of nine primary health care centres. The intralesional treatment was applied five times every other day. Clinical follow-up after six-months of treatment showed a 77% healing proportion and 5% of therapeutic failure among 152 enrolled patients. The drug volume used in the intralesional procedure was on average 1.7 mL/ulcer treated. In conclusion, the strategy used was successful and effective, accomplishing a healing proportion similar to the long standardized treatment with a reduced time of administration, no severe side effects, and it is feasible to conduct by trained health staff. Our study supports the current PAHO/WHO recommendation for the intralesional administration of pentavalent antimonials for the treatment of cutaneous leishmaniasis.

Estimating the global demand curve for a leishmaniasis vaccine: A generalisable approach based on global burden of disease estimates

Background

A pressing need exists to develop vaccines for neglected diseases, including leishmaniasis. However, the development of new vaccines is dependent on their value to two key players–vaccine developers and manufacturers who need to have confidence in the global demand in order to commit to research and production; and governments (or other international funders) who need to signal demand based on the potential public health benefits of the vaccine in their local context, as well as its affordability. A detailed global epidemiological analysis is rarely available before a vaccine enters a market due to lack of resources as well as insufficient global data necessary for such an analysis. Our study seeks to bridge this information gap by providing a generalisable approach to estimating the commercial and public health value of a vaccine in development relying primarily on publicly available Global Burden of Disease (GBD) data. This simplified approach is easily replicable and can be used to guide discussions and investments into vaccines and other health technologies where evidence constraints exist. The approach is demonstrated through the estimation of the demand curve for a future leishmaniasis vaccine.

Methodology/Principal findings

We project the ability to pay over the period 2030–2040 for a vaccine preventing cutaneous and visceral leishmaniasis (CL / VL), using an illustrative set of countries which account for most of the global disease burden. First, based on previous work on vaccine demand projections in these countries and CL / VL GBD-reported incidence rates, we project the potential long-term impact of the vaccine on disability-adjusted life years (DALYs) averted as a result of reduced incidence. Then, we apply an economic framework to our estimates to determine vaccine affordability based on the abilities to pay of governments and global funders, leading to estimates of the demand and market size. Based on our estimates, the maximum ability-to-pay of a leishmaniasis vaccine (per course, including delivery costs), given the current estimates of incidence and population at risk, is higher than $5 for 25–30% of the countries considered, with the average value-based maximum price, weighted by quantity demanded, being $5.7–6 [$0.3 - $34.5], and total demand of over 560 million courses.

Conclusion/Significance

Our results demonstrate that both the quantity of vaccines estimated to be required by the countries considered as well as their ability-to-pay could make a vaccine for leishmaniasis commercially attractive to potential manufacturers. The methodology used can be equally applied to other technology developments targeting health in developing countries.

Efficacy of topical Miltefosine formulations in an experimental model of cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a neglected tropical disease endemic in ~ 90 countries, with an increasing incidence. Presently available pharmacotherapy implies the systemic administration of moderately/very toxic drugs. Miltefosine (Milt) is the only FDA-approved drug to treat CL via the oral route (Impavido®). It produces side effects; in particular, teratogenic effects are of concern. A topical treatment would have the great advantage of minimising the systemic circulation of the drug, preventing side effects. We prepared dispersions containing Milt and liposomes of different compositions to enhance/modulate trans-epidermal penetration and evaluated in vitro and in vivo efficacy and toxicity, in vitro release rate of the drug and particles size stability with time. Treatments were topically administered to BALB/c mice infected with Leishmania (Leishmania) amazonensis. The dispersions containing 0.5% Milt eliminated 99% of the parasites and cured the lesions with a complete re-epithelisation, no visible scar and re-growth of hair. Fluid liposomes decreased the time to heal the lesion and the time needed to eliminate viable amastigotes from the lesion site. Relapse of the infection was not found 1 month after treatment in any case. Ultraflexible liposomes on the other hand had no significant in vitro effect but decreased in vivo efficacy. A topical Milt formulation including fluid liposomes seems a promising treatment against CL.