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

Abstract

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.

Leishmaniasis Vaccines: Applications of RNA Technology and Targeted Clinical Trial Designs

“…Unfortunately, despite the plethora of preclinical evaluations multiple factors have precluded advancement of more than a few Leishmania targeting vaccines to clinical trial. The sheer volume of potential vaccine platforms and antigen targets identified, the substantial economic impact of producing these as GMP-grade, and the lack of availability of safe and effective adjuvants with which to enhance or sustain responses, has led to reticence in advancing to trial candidates that appear to have 'room for improvement' [12][13][14][15]. Further, given that infection is reliant on sand fly vector transmission and sand fly populations are impacted by seasonal variation and micro-geography, pre-planning for enactment in regions with sufficiently high parasite transmission at time of trial is both difficult and unassured.…”

Clinicopathological characteristics of cutaneous and mucocutaneous leishmaniasis in patients treated with TNF‐α inhibitors

“…1 The clinical spectrum ranges from self-curing cutaneous lesions to mucocutaneous disease Clinical presentation and outcome are the result of the interaction of parasite characteristics, vector biology and host factors, including nutritional status, co-infection and, ultimately, the immune response. 1,4 On the other hand, there is an increase in the use of biologic drugs in the treatment of inflammatory diseases. As a result, there is a growth in the number of cases of leishmaniasis in patients subjected to iatrogenic immunosuppression.…”

“…Clinical presentation and outcome are the result of the interaction of parasite characteristics, vector biology and host factors, including nutritional status, co‐infection and, ultimately, the immune response 1,4 . On the other hand, there is an increase in the use of biologic drugs in the treatment of inflammatory diseases.…”

Klinisch‐pathologische Eigenschaften kutaner und mukokutaner Leishmaniose bei mit TNF‐α‐Inhibitoren behandelten Patienten

“…Dazu gehören Ernährungszustand, Ko-Infektionen und letztlich die Immunreaktion. 1,4 Andererseits werden zunehmend Biologika zur Behandlung entzündlicher Erkrankungen eingesetzt. Infolgedessen gibt es vermehrt Leishmaniosen bei Patienten unter iatrogener Immunsuppression.…”

“…Klinisches Erscheinungsbild und Verlauf resultieren aus der Interaktion zwischen Eigenschaften des Parasiten, Biologie des Vektors und Faktoren des Wirts. Dazu gehören Ernährungszustand, Ko‐Infektionen und letztlich die Immunreaktion 1,4 . Andererseits werden zunehmend Biologika zur Behandlung entzündlicher Erkrankungen eingesetzt.…”