* Modest reduction of 30 percent in malaria risk in babies
* Final-stage trial data leaves vaccine's future in doubt
* GSK plans to push ahead with vaccine development
By Kate Kelland and Ben Hirschler
LONDON, Nov 9 The world's first potential
malaria vaccine proved only 30 percent effective in African
babies in a crucial trial, calling into question whether it can
be a useful weapon in the fight against the deadly disease.
The surprisingly poor result for the vaccine, which
GlaxoSmithKline has been developing for three decades,
leaves several years of work ahead before a protective malaria
shot could be ready for countries that desperately need one.
Malaria, a mosquito-borne parasitic disease, kills hundreds
of thousands a year, mainly babies in Africa, and scientists say
an effective vaccine is key to hopes to eradicate it.
Philanthropist Bill Gates, who helped fund the GSK vaccine's
development, said further research was now needed to see whether
and how it might be used.
"The efficacy came back lower than we had hoped, but
developing a vaccine against a parasite is a very hard thing to
do," he said in a statement.
Results from the final-stage trial with 6,537 babies aged
six to 12 weeks showed the vaccine provided "modest protection",
reducing episodes of the disease by 30 percent compared to
immunisation with a control vaccine, researchers said on Friday.
That efficacy rate a year after vaccination is less than
half the 65 percent in an earlier trial in babies which analysed
protection rates after six months. It is also a lot less than
the 50 percent rate seen in five to 17
Vaccinating babies, rather than toddlers, is the preferred
option, since the new vaccine could then be added to other
routine infant immunisations. A separate programme for older
children would involve a lot of extra costs.
Eleanor Riley, a professor of immunology at the London
School of Hygiene and Tropical Medicine said the results showed
that GSK's vaccine, called RTS,S or Mosquirix, is potentially
useful, but "not the complete solution".
"The slightly lower than expected efficacy will ... affect
the cost-benefit analysis that health providers and funders will
have to undertake before deciding whether the vaccine represents
the best use of limited financial resources," she said.
NOT GIVING UP
Despite the setback, Britain's top drugmaker said it would
push ahead with developing RTS,S and GSK Chief Executive Andrew
Witty said it could be an important tool in fighting malaria.
"We've been at this for 30 years, and we're certainly not
going to give up now," he told reporters on a conference call.
GSK does not expect to make any profit from the vaccine,
which would only be sold in poor countries.
Witty reiterated a promise that if RTS,S is ultimately
approved for market, it would be priced at cost of manufacture
plus a 5 percent margin, and the margin would be reinvested by
GSK in malaria research.
Given the target market, it is governments and international
groups that will fund the vaccine's roll-out, and they now need
more positive data before deciding whether it is worth buying.
"We will have to have more information to give us a clearer
idea as to how useful this vaccine will be," said Seth Berkley,
CEO of the GAVI Alliance, which funds bulk-buy vaccination
programmes for poorer nations.
In particular, Berkley told Reuters he wanted to see
longer-term data, including the effect of booster shots, and an
analysis of how the vaccine performed in different settings.
Details of the malaria trial, which is Africa's largest ever
clinical trial involving almost 15,500 children in seven
countries, were presented at a medical meeting in Cape Town and
published online by the New England Journal of Medicine.
Witty said he would have liked to have seen efficacy rates
of around 50 percent in infants, but stressed that more data
would become available before the trial ends in 2014 which may
throw more light on why rates of success are so variable.
"It may open up a more customised approach to how this
potential vaccine gets used," he said.
Malaria is caused by a parasite carried in the saliva of
mosquitoes. It is endemic in more than 100 countries worldwide
and infected around 216 million people in 2010, killing around
655,000 of them, according to the World Health Organisation.
Control measures such as insecticide-treated bed nets,
indoor spraying and anti-malaria drugs have helped cut cases and
deaths significantly in recent years, but scientists say it will
take an effective vaccine and many more years work to wipe out
Scientists around the world are working on other potential
malaria vaccines but RTS,S is by far the furthest ahead in