GSK's malaria vaccine shows promising results in tests on babies

A medication, widely used to treat malaria infection in adults and small children, can also be safe and effective in infants less than a year old, according to a paper published Wednesday online in The Lancet, a British medical journal.

Developed by GlaxoSmithKline (GSK), the RTS,S/AS02A vaccine which three years ago shown to be safe and effective in small children aged 1-4 years, can also be administered to infants who are among the most vulnerable to severe disease and death from malaria, the paper stated.

RTS,S or Mosquirix was invented and first developed in 1987 by the scientists at British pharmaceuticals company GSK and the company has overseen its development ever since. This is a pre-erythrocytic vaccine candidate based on Plasmodium falciparum circumsporozoite surface antigen.

The latest Lancet study is the phase II trial of candidate malaria vaccine RTS,S conducted at the Manhiça Health Research Centre (CISM) in Mozambique by a team of researchers, lead by physician Pedro Alonso, director of the Barcelona Center for International Health Research at the Hospital Clinic of the University of Barcelona, and the Mozambique Ministry of Health.

In a 2004 trial, the phase I trial of candidate malaria vaccine RTS,S, the researchers had found that the vaccine was safe, well tolerated, and immunogenic in young children one to four years old. The trial showed for the first time that the vaccine could protect children against infection or death. That study, which also was headed by Dr. Alonso, had included 2,022 children aged 1 to 4 and showed protection from infection about 45 percent of the time.

In their new clinical trial, Dr. Alonso and his fellow researchers studied only 214 infants between 10 and 18 months at the Manhiça Health Research Center in rural southern Mozambique. Half the infants received doses of the vaccine, while a control group received a hepatitis B vaccine.

The primary objective of the new trial was to show only that the vaccine was safe at such young ages. However, it also showed efficacy in reducing risk of catching malaria.

After receiving the full three doses of vaccine the infants showed 65% fewer new infections and clinical illnesses than did those in the control group. And among all infants who had received at least one doze of vaccine, there were 35 percent fewer malaria episodes.

“We have shown for the first time that a vaccine can reduce the risk of malaria infection in young African infants exposed to intense P. falciparum transmission,” said Dr. Alonso. “These tantalizing and unprecedented results further strengthen the vision that a vaccine may contribute to the reduction of the intolerable burden of disease and death caused by malaria.”

Although, the Phase II trial showed promising results, but a large-scale Phase III study will be required to definitively determine the efficacy of the vaccine in children of all ages. Encouraged by the data from recent trial, researchers hope to begin a larger trial late next year.

According to Ripley Ballou, vice president of global clinical research and development at GSK Biologicals, that larger trial will enroll at least 16,000 children from as many as 10 areas in seven African countries. The researchers hope the results of that trial could come as soon as 2011 if all trials go well.