for at Least 15 Months, Study Says

GlaxoSmithKline Plc’s experimental malaria vaccine, already shown to cut the risk of children contracting the disease by half after 8 months, was equally effective after 15, a study showed.

Youngsters in Africa who got the shot, called Mosquirix, were 46 percent less likely to contract malaria than those who received a rabies vaccine, according to the study published in the journal Lancet Infectious Diseases.

The findings suggest the London-based drugmaker may have succeeded where others have failed in developing the world’s first effective shot against the deadliest mosquito-borne disease. Glaxo expects to have the results of final-stage trials by late this year or early next, Chief Executive Officer Andrew Witty said in October.

“We’ve never had a malaria vaccine get this far in its development and continue to show such promise,” Robert Newman, director of the World Health Organization’s Global Malaria Programme, said in a telephone interview today. “It’s promising and encouraging.”

Malaria infected about 225 million people and killed about 781,000 in 2009, mostly children in sub-Saharan Africa, the Geneva-based WHO said in December. That makes it the world’s third-deadliest infectious disease behind AIDS and tuberculosis.

Researchers including Philip Bejon, from the Kenya Medical Research Institute in Kilifi, Kenya, tested the vaccine on more than 800 children between ages 5 and 17 months in Tanzania and Kenya. The children either received a rabies vaccine or Mosquirix with a so-called adjuvant designed to boost the effect.

New Analysis

An initial analysis, published in December 2008, showed the vaccine cut the number of children infected with malaria by 53 percent after 8 months. The new analysis found “no evidence of waning efficacy,” Bejon and colleagues wrote.

The most common adverse events were pneumonia, fits with fevers and stomach inflammation, with fewer events reported among children who received the malaria vaccine compared with those who got the rabies shot. The researchers are now studying the vaccine in 15,000 infants in seven countries.

Glaxo expects the cost of the vaccine, if successful, to be “the lowest practical cost sustainable over time,” Witty told reporters on a conference call in October. The drugmaker will “price it at the cost of manufacturing, with only a very small return, around 5 percent,” which Witty has pledged to deploy in research for more treatments of neglected tropical diseases.

The study was funded by Glaxo and the Bethesda, Maryland- based PATH Malaria Vaccine Initiative, which is in turn sponsored by the Bill and Melinda Gates Foundation, the world’s richest charity.

Assuming results of the next trial are positive, Glaxo plans to seek regulatory approval for the shot in Europe, Stephen Rea, a spokesman, said in a telephone interview today. The WHO wants to wait for data on the effectiveness of the vaccine after 30 months, due in 2014, before it makes a policy recommendation on the vaccine, Newman said.

To contact the reporter on this story: Simeon Bennett in Singapore at sbennett9@bloomberg.net