Results Of A Malaria Vaccine Initiative Offer Rays Of Hope For Africa’s Six Million Children

A new tool to tackle Africa's top killer of children under five could be in the pipeline, after two studies published today in the New England Journal of Medicine show that a leading vaccine candidate could offer the much-needed protection against this deadly disease.

The studies reveal that the malaria vaccine candidate RTS,S/AS01E, provides both infants and young children with substantial protection against malaria and reinforces a case for the next stage of clinical trials.

"The studies reported a 53% reduction in clinical malaria episodes in 5-17 month old children who had been vaccinated over an eight-month period. This is significant and argues for the need for a phase three trial," says Prof Kevin Marsh, the Scientific team leader of the Kenya Medical Research Institute (KEMRI), Centre for Geographical Medicine Research (CGMR)-Coast, one of the trial sites for the vaccine.

Commenting on the results, Dr Norbert Peshu, the Director of the KEMRI Centre for Geographic Medicine Research-Coast, says: "The results we are reporting today together with our colleagues from Tanzania are encouraging to all of us who are working to develop this vaccine. If this vaccine proves satisfactory in large scale Phase III testing and is adopted by African nations, we could have an important new tool to help save our children from malaria."

"The related study done in Bagamoyo, Tanzania shows that the vaccine can be safely and easily administered as part of existing national immunization programs in infants and reported a 65% reduction time to a first malaria infection over a six month period," explains Philip Bejon, the lead author from the KEMRI Wellcome Trust Programme.

The results from Kilifi have been presented this evening (Kenyan time) at a conference of the American Society for Tropical Medicine and Hygiene (ASTMH) in New Orleans, LA, U.S.A by Dr Ally Olotu of the KEMRI Wellcome Trust Programme.

RTS,S is the leading candidate in a global effort led by the PATH Malaria Vaccine Initiative (MVI) to develop a malaria vaccine. Malaria currently kills almost one million people each year - most of them young children in Africa, the intended recipients for this vaccine candidate.

"Never before has the challenge been greater than now. We need to channel resources and conduct further studies to ensure this vaccine becomes a reality," adds Dr Monique Wasunna, the Acting Director of KEMRI.

The studies published today build on previous findings indicating the efficacy of RTS,S, including a Phase II trial, published in The Lancet in 2007, that demonstrated "proof of concept" that RTS,S could prevent infection in infants.

The vaccine was co-invented by Joe Cohen, Vice-President for Emerging Diseases, HIV & Vaccines Research & Development at GSK Biologicals.

"Malaria is a public health issue in Kenya and these results are important to us at the Ministry. We need to intensify efforts to find a vaccine so as to save Kenyan children from unnecessary deaths due to malaria," says Dr Shahnaaz Sharif, Ag Director for Public Health and Sanitation at the Ministry of Health, Kenya.

"The fact that this vaccine can be administered alongside other childhood vaccines is very encouraging," says Dr Isaac K. Mugoya, Deputy Head of the Ministry of Health's Division of Vaccines and Immunizations.

Dr Elizabeth Juma, Head of the Division for Malaria Control, had this to say: "Results from the vaccine study are encouraging. We also eagerly await the results from the current studies going on in Africa including Kenya on the same vaccine. If these are also as good, then vaccines may be an additional strategy in the war against malaria."

The District Medical Officer of Health for Kilifi, Dr Benjamin Tsofa in whose district the study took place, says: "This offers one of the greatest glimmers of hope for winning the war against malaria in Africa."

The team for the study comprised researchers from the KEMRI-Wellcome Trust Programme (Kilifi, Kenya), the National Institute for Medical Research (Tanzania), the Joint Malaria Programme (Korogwe, Tanzania) and other institutions in collaboration with GSK and the PATH Malaria Vaccine Initiative (MVI).

About RTS,S and Phase III

The pediatric clinical development of RTS,S in Africa began in 2001 through a public-private partnership between MVI and GSK. The vaccine was first formulated in laboratories at GSK Biologicals' headquarters in Belgium in the late 1980s as part of a collaboration with the U.S Walter Reed Army Institute of Research. With the rollout of Phase II trials, African research centers in five countries and collaborating institutions, joined the partnership.

Pending regulatory approvals by national and international regulatory agencies, the multi-center Phase III trial, with 11 centers in seven nations, is on track to enroll up to 16,000 infants and children. Dr Patricia Njuguna who will lead the Kilifi team on this trial says: "The trial will seek to determine the length of the vaccine's protection and evaluate the vaccine's effectiveness in different parts of Africa, where intensity of malaria transmission may differ. In addition, safety will continue to be closely monitored."

Funding for the development of this vaccine candidate has been made possible through a US$107.6 million grant from the Bill & Melinda Gates Foundation to the PATH Malaria Vaccine Initiative. GSK has invested $300 million to date and expects to invest another $50-100 million before the vaccine enters the regulatory approval process.

RTS,S is designed to trigger the immune system to defend against the Plasmodium falciparum malaria parasite as soon as it enters the human host's bloodstream and/or when the parasite infects liver cells. This prevents the parasite from maturing and multiplying in the liver and from re-entering the bloodstream, where the host would begin to show symptoms of infection.

To stimulate an immune response to the malaria parasite, RTS,S fuses a critical circumsporozoite (CS) protein, the surface protein that helps the parasite invade human liver cells, with a protein found in GSK Bio's hepatitis B vaccine. The addition of GSK's proprietary Adjuvant System strengthens the immune response even further.

For more information, contact:

Justa Wawira
Kenya Medical Research Institute (KEMRI),
Centre for Geographic Medicine Research-Coast
Tel +254 41 7522324/7522063/7525063/7522014/7522154
Fax +254 41 7522390 Mobiles +254 722 203417, 725 242233, 722 747571
Email: JWawirakilifi [dot] kemri-wellcome [dot] org