Efficacy trial of the world's most clinically advanced malaria vaccine candidate underway

Nov 3 2009

Pivotal testing of RTS,S is on track for target enrollment of 16,000 children

A pivotal efficacy trial of RTS,S, the world's most clinically advanced malaria vaccine candidate, 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, researchers announced Tuesday at the 5th Multilateral Initiative on Malaria Pan-African Malaria Conference.

Developing a vaccine against malaria, a scientific challenge for decades, is critical to defeating the disease. A vaccine would complement existing interventions, such as bed nets and effective drug therapies. GlaxoSmithKline Biologicals' (GSK Bio) RTS,S is the first malaria vaccine candidate to demonstrate significant 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 malaria vaccine could help save countless lives and redefine the future for Africa's children," said Dr. Patricia Njuguna, RTS,S principal investigator (KEMRI-Wellcome Trust, Kilifi, Kenya) and chair of the Clinical Trials Partnership Committee, a collaboration of African research institutions, MVI, and GSK Bio that is leading the clinical development of RTS,S. "Communities all across Africa are dedicated to this future and are participating to ensure that we develop a vaccine with an acceptable safety and efficacy profile."

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. For example, some trial sites are located in areas where there is a year-round threat of malaria, while others experience only seasonal transmission.

All of the research centers were chosen for their track record of world-class clinical research, strong community relations and commitment to meeting the highest international ethical, medical, clinical and regulatory standards.

"This is a tremendous 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 of R&D, Vaccines for Emerging Diseases and HIV, at GSK

Biologicals. "The Phase III trial is a huge undertaking that depends on effective coordination between researchers, regulators, families and communities. Everyone involved has invested significant energy and resources to pave the way for what could become the world's first malaria vaccine."

Recent Phase II studies showed that RTS,S reduced clinical episodes of malaria by 53 percent over an eight-month follow-up period. Findings from a Phase II trial initiated in 2002 and conducted with more than 2,000 children in southern Mozambique, published in the medical journal The Lancet in 2004 and 2005, showed that RTS,S was efficacious for at least 18 months in reducing clinical malaria by 35 percent, and severe malaria by 49 percent. , In addition, RTS,S was shown to have a promising safety and tolerability profile when used alongside the World Health Organization's (WHO) standard infant vaccines.

"This historic trial could lead to the availability of a vaccine with the potential to save the lives of hundreds of thousands of African children, if the data are positive," said Dr. Christian Loucq, director of the PATH Malaria Vaccine Initiative. "But development is only half the mission; MVI and its partners are committed to ensuring this vaccine reaches those who need it most. We hope the international community will respond by starting to prepare for the day when-if all goes well-this vaccine will be available for distribution and use."