Experimental Malaria Vaccine Using Weakened Malaria Parasite To Begin Human Trials

Main Category: Tropical Diseases
Also Included In: Immune System / Vaccines;  Clinical Trials / Drug Trials
Article Date: 22 Jul 2009 - 3:00 PDT

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An experimental malaria vaccine created by "an approach pioneered more than 30 years ago but abandoned as wildly impractical" is about to be tested on humans, the Seattle Times reports. The vaccine, made up of weakened malaria parasites, provided 100 percent protection in mice. The Seattle Biomedical Research Institute's (SBRI) Stefan Kappe - who is leading a group of researchers from Australia, Canada and Japan - said the group is "shooting for 90 percent-plus protection."

According to the Seattle Times, SBRI was "flooded with calls and e-mails last year" when it "announced plans for a local facility where volunteers can participate in malaria-vaccine trials. The facility won't open until mid-2010, so the initial trials on Kappe's vaccine are tentatively scheduled to start in January at Walter Reed Army Medical Center in Maryland. U.S. Food and Drug Administration approval is required." The Bill & Melinda Gates Foundation is funding the $17 million project.

"Many experimental drugs falter in the leap from mouse to man," writes the newspaper and even if the experiments are successful, it could be almost 10 years before a new vaccine would be available, Kappe said. "When laboratory mice were inoculated with the weakened parasites, the bugs lodged in their livers but were unable to proliferate and burst into the bloodstream where malaria wreaks its havoc. Instead, the harmless parasites primed the animals' immune systems to fight future infections," according to the Seattle Times. Although the immunity lasted throughout the mice's lives, it probably will not provide lifetime protection in humans, "but it could be maintained through booster shots, Kappe said," the newspaper writes.

The article includes information about the history of malaria vaccine development and other experimental vaccines (Doughton, 7/20).

RTS,S Kenya Testing Examined

In related news, Business Daily/allAfrica.com examines the RTS,S malaria vaccine trials that are currently underway in Kenya. "The first dose was administered at the Siaya District Hospital last week under the auspices of the Kemri/CDC Research and Public Health Collaboration. The Kenyan launch follows the initiation of the Phase III trial in Tanzania in May," writes the newspaper.

After the first vaccine was administered, Mary Hamel, head of the Malaria Branch at Kemri/CDC and principal investigator of its Phase III malaria vaccine trial, said, "This is a very exciting moment, the culmination of over 30 years of intensive research on malaria vaccines. If RTS,S works as well as it has in earlier trials, its introduction could result in hundreds of thousands of lives saved." According to Business Daily/allAfrica.com, the Phase III trial will "demonstrate how the vaccine performs in two groups of children - one aged 6-12 weeks and a second aged 5-17 months - in different transmission settings across a wide geographic region" (Menya, 7/20).

This information was reprinted from globalhealth.kff.org with kind permission from the Henry J. Kaiser Family Foundation. You can view the entire Kaiser Daily Global Health Policy Report, search the archives and sign up for email delivery at globalhealth.kff.org.

© Henry J. Kaiser Family Foundation. All rights reserved.

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