G6PD deficiency diagnosis

Presently, treatment with 8-aminoquinolines, a class of drugs that includes primaquine, is the only option for killing the liver form of the P. vivax parasite to prevent relapse and transmission. The problem with these drugs is that they tend to cause serious side effects in patients with severe glucose-6-phosphate dehydrogenase (G6PD) deficiency, which is a hereditary condition prevalent in areas in which malaria often occurs—according to a PATH fact sheet, some 400 million people worldwide are G6PD-deficient. While the World Health Organization recommends testing for G6PD deficiency before administering primaquine, current diagnostic tests for the condition are ill-suited for remote use in the tropic areas malaria most often appears in.

PATH is working with Mologic on the development of a novel qualitative point-of-care G6PD rapid diagnostic test (RDT). The Mologic RDT has been optimized for use in hot, humid environments at the community level with a simple positive or negative result to inform users of the presence of G6PD deficiency. PATH and Mologic are looking at 2019 for the market release of the first product variant, and PATH is aiding the latter company in commercializing and regulatory efforts.

“We are honored to have developed this new rapid diagnostic test technology for G6PD deficiency that combines the direct measurement of enzyme activity into the simple lateral flow line format similar to that used in home pregnancy testing, based on Mologic’s enzyme activity detection format,” said Paul Davis, co-founder and chief scientific officer of Mologic. “We would like to thank PATH for driving the development of this key test to support malaria treatment and leading efforts to bring the test to market. Mologic looks forward to continuing this partnership with PATH in advancing essential diagnostic technology to address important health issues.”

PATH is developing a number of G6PD deficiency tests, from tests that determine G6PD activity and hemoglobin in whole blood to qualitative tests that can exclude patients with severe G6PD deficiency. The organization has developed GeoDx, which it describes as “an interactive tool to model demand and cost estimates for various G6PD tests in different geographic and epidemiological settings,” as well as a specimen repository of blood samples presenting with a range of G6PD activity. PATH is also working with GlaxoSmithKline to develop tests supporting the use of tafenoquine, an investigational 8-aminoquinoline-based drug. Tafenoquine is under development by GlaxoSmithKline and Medicines for Malaria Venture as a way to target P. vivax hypnozoites in one treatment.

PATH’s funding to support the advancement of G6PD diagnostic tools comes from UKAid from the United Kingdom Department for International Development and the Bill & Melinda Gates Foundation.

And PATH isn’t the only organization to benefit from the Gates Foundation’s generosity of late—early May saw The Scripps Research Institute (TSRI) announce the receipt of a $12-million grant from the Bill & Melinda Gates Foundation to support research into malaria and flu vaccines. The Gates Foundation has awarded nearly $2 billion in grants to date in support of malaria research, and notes on its website that eradicating malaria is one of its top priorities.

The grant will be administered by Ian Wilson, Hansen Professor of Structural Biology at Scripps Research and chair of the Department of Integrative Structural and Computational Biology. The Scripps team intends to use the funding to continue pursuing studies of antibodies capable of neutralizing multiple strains of influenza and malaria. Dr. Dennis Burton, chair of Scripps Research’s Department of Immunology and Microbiology and scientific director of the International AIDS Vaccine Initiative Neutralizing Antibody Center and of the National Institutes of Health’s Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, will co-lead the study. Drs. Andrew Ward and William Schief will serve as co-investigators.

The malaria component of this project is part of a broader collaboration involving multiple organizations.

“We have a great team here at Scripps Research for rational design of vaccines, and we look forward to taking on malaria and flu with this generous funding from the Gates Foundation,” Burton said in a press release.

TSRI and PATH have not only both benefited from Gates Foundation funding, they’ve also worked together on malaria research before. In November 2017, a research team from the California campus of the Scripps Institute and PATH detailed their findings on how human antibodies bind to the circumsporozoite protein, a malarial surface protein, to protect against the parasite.