A new strategy in the war on malaria
Bethesda nonprofit launches collaboration to develop novel vaccine
A nonprofit in Bethesda is developing a new weapon in the global vaccine arsenal against malaria.
The Malaria Vaccine Initiative, which already funds efforts to develop vaccines to prevent people from contracting the deadly infection, said Friday it is taking a novel tack in its war on malaria. The group is launching a collaboration with the Johns Hopkins Bloomberg School of Public Health in Baltimore and the Sabin Vaccine Institute in Washington, D.C., to produce a new type of vaccine that would break the mosquito-human-mosquito malaria transmission cycle.
The vaccine would be given to both infected and uninfected people. They would then develop antibodies, which, when transmitted to another mosquito through a bite, would prevent this second mosquito from producing in its gut the malaria parasite it would otherwise transmit to another victim through a bite.
Malaria kills nearly 900,000 people per year, most of them children younger than 5, according to the initiative, which is part of the Program for Appropriate Technology in Health of Seattle. PATH is heavily funded by the Bill & Melinda Gates Foundation.
"The heart-breaking devastation caused by malaria cannot be overstated," said Peter Agre, Nobel laureate and director of the Johns Hopkins Malaria Research Institute, in a statement. "Blocking transmission by novel vaccines may provide the approach needed to stop the epidemic. MVI deserves great credit for supporting potentially exciting research that would otherwise be abandoned due to lack of precedent."
"Although eradication is a very long-term and aspirational goal, we are excited by the potential of transmission-blocking vaccines to significantly limit the spread of malaria infection," said Christian Loucq, director of the initiative, in a statement. "In combination with other interventions, we believe a successful [transmission-blocking vaccine] would provide another important tool in the fight against malaria."
Officials at the Bethesda nonprofit were not available for further comment, including how much funding the new collaboration will receive.
Under the collaboration, the Sabin institute, which is also funded by the Gates foundation, will work to produce large quantities of the antigen, called AnAPN1, which would prompt the body to produce the antibodies needed to disrupt transmission.
Johns Hopkins scientists will then use that antigen in immunization trials on mice, studying its ability to block transmission and any potential side effects of concern. If results, which are expected in mid-2011, are positive, more preclinical tests may be conducted before clinical trials are held.
"The antibodies that we have produced are effective against multiple malaria parasites and, therefore, this antigen may constitute the basis for a future universal' or pan-malaria transmission-blocking vaccine," said Rhoel Dinglasan of Johns Hopkins, lead researcher on this project, in the statement. "This could have a tremendous impact on malaria transmission, even extending beyond those individuals we can reach through a vaccination campaign, since the transmission-blocking component is intended to protect the population as a whole."
The collaboration is part of the Malaria Vaccine Initiative's redesigned research and development strategy, which takes a broader look at malaria vaccine development with the goal of a vaccine that is at least 80 percent effective against clinical disease for more than four years by 2025.
Not all experts are sold on the transmission-blocking concept, however.
Stephen L. Hoffman, CEO of Sanaria, a Rockville company that also receives funding from the Gates foundation and works with the Malaria Vaccine Initiative, said there are "a lot of ifs" in the new approach.
"The concept with that approach if you could immunize an entire community, if you had a highly effective vaccine is it could reduce or eliminate transmission," said Hoffman, whose company is developing a vaccine that is designed to prevent the infection of individuals. "This type of approach, in a world with wonderful resources, could be complementary to what we're doing."
Another key difference, he said, is that the new initiative targets only two malaria-related proteins, whereas Sanaria's vaccine candidate targets all such proteins, which could number in the hundreds or thousands.
"Ours is a whole-parasite approach," Hoffman said. "Theirs is designed to block transmission, but not stop infection. Ours would prevent infection and transmission."
Sanaria is currently testing its candidate in phase 1 trials in Bethesda and Baltimore, and expects results in late spring or summer, he said.
Correction: The original version of this article said the new transmission-blocking vaccine would be given to people infected with malaria. It would be given to both infected and uninfected people.