A new malaria vaccine by GlaxoSmithKline has evoked a 100-fold antibody response in childern during clinical trials conducted in the West African state of Mali.
The new vaccine which targets the most common falciparum malaria parasite has been tested in 100 Malian children aged 1 to 6.
The immunity boosting adjuvant is a blood stage vaccine that targets the falciparum malaria parasite after reach the bloodstream and into the liver, where it transforms into a new form called a merozoite. Merozoite infects new red blood cells causing fever and chill, the coomon symptoms of malarial disease.
The vaccine has produced antibody levels as high or higher in children than antibody levels found in adults, who have developed immune responses to the parasite over lifelong exposure to malaria.
“These findings imply that we may have achieved our goal of using a vaccine to reproduce the natural protective immunity that normally takes years of intense exposure to malaria to develop,” Christopher Plowe, professor and chief of the malaria section at the Center for Vaccine Development at the University of Maryland’s school of medicine, and a lead author of the study was quoted as saying.
University of Maryland researchers collaborated with a group of Malian researchers from the Malaria Research and Training Center, led by Mahamadou Thera and Ogobara Doumbo for the study.
Now the researchers plan to test the vaccine in 400 more children to ascertain its efficacy.
The study will also examine whether the single-strain vaccine can be effective against the other forms of malarial parasites as well.
Glaxo is currently evaluating another anti-malarial vaccine Mosquirix.
Mosquirix vaccine is currently in final-stage clinical trials, GlaxoSmithKline reported.
Mosquirix will be tested in some 16,000 children and infants at 11 trial sites in seven countries.
Mosquirix — also known as RTS,S uses a recombinant protein that fuses part of the P falciparum circumsporozoite protein (CSP) with hepatitis B surface antigen. Combined with a proprietary adjuvant, RTS,S induces production of antibodies and T cells that interfere with the ability of the malaria parasite to infect humans. Early development of RTS,S was undertaken by GSK in collaboration with the US Walter Reed Army Institute of Research.
Earlier clinical tests suggest Mosquirix is 50-55 percent effective in preventing episodes of clinical malaria.
Mosquirix vaccine is likely to be filed for regulatory approval by GSK in 2011, under a special review procedure established by the European Medicines Agency for products designed for use in the developing world. Based on normal timelines that could see Mosquirix reaching the market in 2012.
GlaxoSmithKline, the world’s second largest drugmaker, has invested more than $300 million in the vaccine to date and expects to invest at least another $100 million.
However, Glaxo will be selling Mosquirix vaccine at preferential prices to international groups like the Global Alliance for Vaccines and Immunization, with its target market in Africa.
Malaria kills around one million people a year — most of them young children in sub-Saharan Africa.
One child dies of malaria every 30 seconds, according to the World Health Organisation.