Neglected diseases are rarely headline-grabbing pandemics -- they exist in the shadows, afflicting one billion people who are already burdened by poverty and limited access to healthcare. And, despite the dire need, in the impoverished regions where these diseases often lurk in the shadows of neglect, with little hope for effective treatment, research and development (R&D) efforts suffer chronic lack of funding.

The reason they are called “neglected” is because these 20 diseases—the lion's share of which are concentrated in low- and middle-income countries (Lmics) , especially sub-Saharan Africa—are almost absent from the global health agenda.

Even today, when the focus is on Universal Health Coverage, Neglected Tropical Diseases (NTD) have limited resources and are almost ignored by global funding agencies. New research by Policy Cures Research, a think tank based in Sydney, Australia and project partners established that $97.9 billion was put into R&D for neglected diseases between 1994-2022.

For comparison R&D expenditures in the pharmaceutical industry totalled $244 billion globally in 2022 only.

In total, neglected disease R&D represents a mere 1-2 percent of global spending on all health-related R&D.

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Researchers note the current era marks significant progress, with the generation of hundreds of new products and a robust pipeline poised for neglected diseases. But they observe that, even though over the past 20 years, game-changing products have significantly lowered the global burden of NTDs, there remains notable product gaps.

Policy Cures Research and research partners (Anthologie, Avenir Health, the African Population and Health Research Centre, Centre for Global Development and the Stanford Innovative Medicines Accelerator), have shown the chasm between the needs of the afflicted and the resources allocated, urging a re-evaluation of global health priorities.

Their research shows that diseases persist not because they are incurable, but because they are ignored due to the exorbitant cost of developing new treatments, with estimates ranging from $43.4 million to $4.2 billion, for diseases that predominantly affect the poor, and where the return on investment is deemed too low.

In parts of the world afflicted by these neglected diseases, such as chagas, dengue fever, leishmaniasis and schistosomiasis, 200,000 deaths occur and 19 million disability-adjusted life years (Dalys’) are lost annually.

Even when it does happen, the distribution of R&D funding and pipeline products has seen the gains concentrated in HIV/Aids, malaria and tuberculosis, with nearly 72 percent of the total lives saved due to reductions in mortality from these “Big 3”. According a related study by the G-Finder, where funding is highly concentrated has little correlation with burden of disease.

The Big 3 accounted for 125 million Dalys in low- and middle-income countries in 2004 and received nearly 80 percent of total funding; while other high-burden diseases as measured by Dalys such as pneumonia and the diarrhoeal illnesses accounted for 165 million Dalys in these countries in the same year but received less than six percent of total funding collectively.

Likewise, helminth infections received less than half the funding of kinetoplastid diseases although their disease burden was three times higher (12 million Dalys in 2004 compared to 4 million Dalys for the kinetoplastid diseases), while dengue had a disease burden 20 times lower than helminth infections at 600,000 Dalys in 2004 but received nearly twice as much funding.

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On the bright side, the research revealed an increase in product approvals for neglected diseases over the past decade. Between 2013 and 2023, 67 percent (123) of the approved products were for neglected diseases, compared to just 33 percent (60) from 2001 to 2012.
Additionally, recent years have seen the launch of entirely new product classes for these diseases.

“183 diagnostic, drug, vaccine, microbicide and vector control products (VCPs) targeting neglected diseases have been approved by a regulatory agency or prequalified by the World Health Organisation (WHO) between 1999 and December 2023.

Moreover, there are 752 active candidates in the neglected disease pipeline and sustained investment is expected to deliver another 182 lifesaving products by the year 2040,” the research shows.

Of the 183 products, 85 target just three disease areas, with 47 targeting malaria, 20 diarrhoeal diseases and 18 TB.

The remainder is split across 12 different neglected disease areas, leptospirosis, hepatitis C, HIV/Aids, helminth infections, kinetoplastids and hepatitis B.

In all this, far more diagnostics have been approved than any other product type. The researchers reckon this is because many diagnostics are relatively simple and far cheaper to develop than drugs and vaccines.

Also because trial sizes necessary to demonstrate sensitivity and specificity are usually far smaller than those powered to show therapeutic or vaccine efficacy, so some tests can go from conception to approval in less than one year.

The 51 approved drugs for neglected diseases make up just more than a quarter of the total product landscape and represent more than three times the number of approved vaccines (16).

And most diseases now have at least one approved diagnostic, the exceptions being histoplasmosis, hookworm, trachoma and scabies. But while most disease groups now have at least one approved drug, only four have approved vaccines. Among them are vaccines for 11 of the 15 neglected disease areas, including HIV/AIDS, tuberculosis and rheumatic fever, drugs for Buruli ulcer and diagnostics for P.vivax malaria.

Alongside the sole approved microbicide (for HIV/AIDS), 23 chemical vector control products have been approved – all targeting malaria-carrying mosquitos

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Barren pipeline of candidates

As of 2023, the neglected disease pipeline had 752 active candidates, representing 27 percent growth since 2019—a net increase of 159 candidates after accounting for product launches. The most significant area of growth was in malaria vaccine candidates, which rose from 42 in 2019 to 65 in 2023.

This is followed by diagnostics for helminths with an increase of 19 candidates, hepatitis B biologics (16), first captured in the pipeline in 2023, dengue diagnostics (15) and drugs (13), and diarrhoeal vaccines (12).

According to Policy Cures Research, the landscape of research and development is shifting, albeit slowly and with vestiges of indefatigability from the past.

Even with candidates, half of the neglected disease pipeline (376 candidates) is made up of candidates for the three major diseases 20 percent (151) malaria, 15 percent (114) tuberculosis and 15 percent (111) HIV/Aids.

This broadly aligns with the allocation of R&D funding, where 71 percent of investment between 2007 and 2022 went to those three diseases.

Most of the remainder are candidates for dengue (44), hepatitis B (34), S. pneumoniae (27), leishmaniasis (24) and hepatitis C (23).
This barren pipeline is coupled with a lack of approved products and persistently low levels of R&D funding.

And even though promisingly, 32 percent (182) of the vaccines and therapeutics pipeline has reached Phase II and III trials, the high cost of late-stage trials, and the 143 additional candidates still in Phase I, underscore the need for significant funding over the coming years to realise the potential for new product launches.