World’s first malaria vaccine works in major trial

SEATTLE/LONDON, (Reuters) –An experimental vaccine  from GlaxoSmithKline halved the risk of African children  getting malaria in a major clinical trial, making it likely to  become the world’s first shot against the deadly disease.

Final-stage trial data released yesterday showed it gave  protection against clinical and severe malaria in five- to  17-month-olds in Africa, where the mosquito-borne disease kills  hundreds of thousands of children a year.

“These data bring us to the cusp of having the world’s  first malaria vaccine,” said Andrew Witty, chief executive of  the British drugmaker that developed the vaccine along with the  nonprofit PATH Malaria Vaccine Initiative (MVI).

While hailing an unprecedented achievement, Witty, malaria  scientists and global health experts stressed that the vaccine,  known as RTS,S or Mosquirix, was no quick fix for eradicating  malaria. The new shot is less effective against the disease  than other vaccines are against common infections such as polio  and measles.

“We would have wished that we could wipe it out, but I  think this is going to contribute to the control of malaria  rather than wiping it out,” Tsiri Agbenyega, a principal  investigator in the RTS,S trials in Ghana, told Reuters at a  Seattle, Washing-ton, conference about the disease.

Malaria is endemic in around 100 countries worldwide and killed some 781,000 people in 2009, according to the World  Health Organisation.

Control measures such as insecticide-treated bednets,  indoor spraying and use of combination anti-malaria drugs have  helped significantly cut the numbers of malaria cases and  deaths in recent years, but experts have said that an effective  vaccine is vital to complete the fight against the disease.

The new data, presented at the Bill & Melinda Gates  Foundation’s Malaria Forum conference in Seattle and published  simultaneously in the New England Journal of Medicine, were the  first from a final-stage Phase III clinical trial conducted at  11 trial sites in seven countries across sub-Saharan Africa.

The trial is still going on, but researchers who analysed  data from the first 6,000 children found that after 12 months  of follow-up, three doses of RTS,S reduced the risk of children experiencing clinical malaria and severe malaria by 56 percent  and 47 percent, respectively.

“We are very happy with the results. We have never been  closer to having a successful malaria vaccine,” said Christian  Loucq, director of PATH MVI, who was at the conference.

Loucq said widespread use of insecticide-treated bednets in  the trial — by 75 percent of people taking part — showed that  RTS,S can provide significant protection on top of other  existing malaria control methods.

Results in babies aged six to 12 weeks are expected in a  year’s time and, if all goes well, GSK believes the vaccine  could reach the market in 2015.

COSTS      

Getting RTS,S to African infants who need it will take a  concerted effort from international funders such as the Gates  Foundation, which helped pay for the research. Health experts  have said it must be cheap enough to be cost-effective.

Gates said the results were a “huge milestone” in the fight  against malaria.

Witty declined to say if a course of three shots would cost  under $10 but told reporters RTS,S would be priced as low as  possible. The company has previously said it would charge only  the cost of manufacturing it plus a 5 percent mark-up, which  would be reinvested into tropical disease research. “We are not  going to make any money from this project,” Witty said.

However, shares in GSK’s small U.S. biotech partner Agenus,  which makes a component of the vaccine, rose more than 40  percent after news of the clinical trial result.

Britain’s minister for international development Andrew  Mitchell said the vaccine “offers real hope for the future.”

“An effective, long-lasting and cost-effective vaccine  would make a major contribution to malaria control,” he told  the conference.

Malaria is caused by a parasite carried in the saliva of  mosquitoes. The RTS,S vaccine is designed to kick in when the  parasite enters the human bloodstream after a mosquito bite. By  stimulating an immune response, it can prevent the parasite  from maturing and multiplying in the liver.

Without that immune response, the parasite gets back into  the bloodstream and infects red blood cells, leading to fever,  body aches and in some cases death.

RTS,S’s co-inventor Joe Cohen said the data were robust and  consistent with earlier trials, which also showed around 50  percent efficacy. Side effects, including fever and  injection-site swelling, were similar in children given RTS,S  and a control vaccine. After working for 24 years on developing the shot, he said  he was “very proud of what we have achieved.”

Some external commentators were cautious about the  vaccine’s potential, but said it was an important development  that should save many lives. Health experts normally like to  see a success rate of 80 percent plus in a vaccine.

“We’re probably not there yet, but this is a really  important advance in science,” Peter Agre, director of the John  Hopkins Malaria Research Institute and a former Nobel prize  winner, told Reuters at the conference.

In an editorial in the New England Journal of Medicine,  Nicholas White of Thailand’s Mahidol University said, “It is  becoming increasingly clear that we really do have the first  effective vaccine against a parasitic disease in humans.”

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