New drugs still lacking for the infectious diseases of poverty

20 May 2010

Paul Chinnock

Source: PLoS ONE (see original article or PDF)

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Citation: Cohen J, Dibner MS, Wilson A (2010). Development of and Access to Products for Neglected Diseases. PLoS ONE 5(5): e10610.

It is well known that the infectious diseases of poverty (IDPs) attract less funding for research than is the case for the priority health concerns of the richer nations. In consequence, the number of new products approved for use in the treatment or prevention of IDPs has been disappointing. Nevertheless, the last few years have seen a welcome increase in research funding. Has this then resulted in more such products becoming available?

US researchers set out to find what products were approved in the period 1975–1999 and to compare this with what has happened more recently (2000–2009).

The researchers had first to define their terms of reference. Their focus was on “neglected” diseases, for which they used the definition employed by the G-FINDER project. This includes the diseases usually classed as neglected tropical diseases (NTDs) but also tuberculosis, malaria, pneumonia and diarrhoeal disease. In addition, products for HIV/AIDS intended specifically for use in developing countries also appear on the list. (For the complete list, see box at the end of this article.)

They employed the methodology of an earlier study [1] and found there had been 56 approvals of drugs for diseases that fell within their “neglected” definition during the period 1975–1999. Most of these drugs (82%) have been added to WHO’s Essential Drugs List (EDL).

In the period 2000 to May 2009, despite the availability of much greater funding, only 26 new drugs and vaccines for neglected diseases reached the approval stage. Of these, WHO has placed 50% on the EDL. (The authors speculate whether the high cost of some of the new products might explain why they are not yet on this list.)

Eleven of the 26 new products were for malaria and ten were for HIV/AIDS. One new drug and two vaccines were for diarrheal diseases, one vaccine was developed against bacterial meningitis, and one new drug was approved for leishmaniasis.

In no other disease category were any new drugs approved in the first nine years of the new millennium. Of particular note is the lack of any new product for tuberculosis, even though this disease has received a major increase in research funding, comparable to that for malaria. (Details of all the new products in both time periods are provided by the researchers in an appendix to their article.)

Amongst other findings of interest, the percentage of approved neglected disease products sponsored by the private pharmaceutical industry was found to have fallen from 83% to 46% between the two time periods, while the percentage sponsored by public-private partnerships (PPPs) increased from 15% to 46%.

The authors point out that there will be an inevitable time lag between the award of new funding to the approval of a product but, they say, “…we do not think it is far-fetched to already be looking for indications of progress in terms of numbers of new approvals, particularly given the fact that the conventional 10–15 year period to register a drug may not invariably apply as numerous products currently being developed by PPPs have been granted accelerated approval times”.

The researchers describe the progress that has been made in product development in recent years as “lopsided, with marked strides in the area of malaria research, yet few end products in others”. They call for a better targeting of research funding. As they also rightly remind us, bringing new products to market is not the ultimate goal. The need to ensure that new tools to fight the infectious diseases of poverty reach all those who need them remains paramount.

“Neglected” diseases as defined in this study

malaria
tuberculosis
bacterial pneumonia and meningitis
diarrhoeal diseases: rotavirus, enterotoxigenic and enteroaggregative E. coli, cholera, shigella, cryptosporidium, giardia,
kinetoplastid diseases: Chagas disease, human African trypanosomiasis, leishmaniasis
soil transmitted helminthiases: ascariasis, ancylostomiasis, necatoriasis, trichuriasis, strongyloidiasis
filarial diseases: lymphatic filariasis, onchocerciasis
schistosomiasis
tapeworm
leprosy
trachoma
Buruli ulcer
Dengue fever
rheumatic fever
typhoid and paratyphoid fever
HIV/AIDS (products with applications specific to the developing world)

Reference

Trouiller P, Olliaro P, Torreele E, Orbinski J, Laing R, et al. (2002). Drug development for neglected diseases: a deficient market and a public-health policy failure. Lancet; 359(9324): 2188–2194. Available from: http://www.ncbi.nlm.nih.gov/pubmed/12090998

2010, Cohen et al