'RTS,S of GlaxoSmithKline Biologicals is the first malaria vaccine candidate to demonstrate efficacy during early development to warrant phase-III testing. It is the leading vaccine candidate in the global effort by the PATH Malaria Vaccine Initiative (MVI) to develop a malaria vaccine.

A pivotal efficacy trial of RTS,S, is now underway in seven African countries: Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and Tanzania. The trial, which is expected to involve up to 16,000 children, is on schedule, with more than 5,000 children already enrolled.

"A malaria vaccine could help save lives of Africa's children," said Dr Patricia Njuguna, RTS,S principal investigator (KEMRI-Wellcome Trust, Kilifi, Kenya) and chair of the Clinical Trials Partnership Committee.

RTS,S is the first vaccine designed primarily for use in Africa, where malaria kills more than 800,000 people every year, the majority of them children under the age of five. By conducting the trial in seven different countries across Sub-Saharan Africa, researchers will be able to evaluate the vaccine candidate's efficacy in a variety of settings, with diverse patterns of malaria transmission.

"This is a major moment in the fight against malaria and the culmination of more than two decades of research, including 10 years of clinical trials in Africa," said Dr Joe Cohen, co-inventor of RTS,S and vice president, R&D, Vaccines for Emerging Diseases and HIV, GSK Biologicals.

Recent phase-II studies showed that RTS,S reduced clinical episodes of malaria by 53 per cent over an eight-month follow-up period.

The phase-III trial will evaluate the vaccine's efficacy in two groups of children. One group, aged six to 12 weeks, will be vaccinated as part of their regular schedule of infant immunizations. The second group includes children aged 5 to 17 months. The vaccine profile is intended primarily for infants, as they and children under the age of five are the most vulnerable to malaria.

Each country hosting a study site has undertaken independent reviews to ensure the trial meets national safety, ethical and legal standards for medical research.

Funding for the development of this vaccine was through Bill & Melinda Gates Foundation, which provided over US$ 200 million to MVI for this project since 2001. GSK has invested more than US$ 300 million and expects to invest at least another US$ 100 million before the completion of the project.