According to theWorld Health Organisation, each year malaria causes an estimated 660,000 deaths worldwide, mostly in Africa, where one child dies of malaria each minute. At present, there is no available vaccine, only preventative measures such as mosquito nets and insecticides which have limited use. In a considerable step forward towards the fight against malaria, British drug firm GlaxoSmithKline (GSK) madeheadline news本月初announcementthat they are seeking regulatory approval for the world’s first malaria vaccine;RTS,S. Whilst there are some other malaria vaccines in development, RTS,S is the most advanced vaccine targetingPlasmodium falciparum，最致命的疟疾寄生虫。可以理解的是，这一消息引起了全世界的实质性兴奋，但是批评家对RT的功效提出了担忧，根据迄今为止的审判，这只是between 30-60%.这意味着RTS，S可能在某些儿童的预防疟疾中很有用，但可能对其他儿童没有影响。到目前为止，对于为什么有些孩子比其他孩子更容易接受RT，也不了解我们如何比其他孩子更容易接受。
In arecent studypublished inBMC Medicine,Philip Bejon和colleagues from the牛津大学analysed Phase II trial data from two RTS,S trial sites to investigate whether peripheral blood monocyte-to-lymphocyte ratios (ML ratio) affected the efficacy of RTS,S among trial participants. This study identified for the first time that ML ratio could be used to identify children most susceptible to the RTS,S vaccine. This finding could also be used to help target future research towards identifying potential mechanisms for low efficacy of RTS,S, in patients with high ML ratio, which may well hold the key for improving overall efficacy of RTS,S.
On efficacy,Sir Andrew Witty, CEO of GSK, commented that:
“while we have seen some decline in vaccine efficacy over time, the sheer number of children affected by malaria means that the number of cases of the disease the vaccine can help prevent is impressive”.
GSK’s announcement to seek regulatory approval of RTS,S despite its known limitations in efficacy are in line with a goal of the疟疾疫苗技术路线图which is to ‘develop and licence a first generation malaria vaccine that has protective efficacy of more than 50%’.
在opinion articlepublished this week inBMC Medicine,Freya Fowkes和colleagues from the Burnet Institute discuss the implications of the licensure of a partially efficacious malaria vaccine with regards to the development of a second generation vaccine. The article discusses the potential advances a second generation vaccine may have; would the second generation vaccine be more efficacious? Or would the second generation vaccine be similar to the first but perhaps cheaper, easier to administer, have a longer duration, or target additional malaria parasites? Each of these potential advances poses unique methodological challenges with regards to the design of clinical trials for second generation vaccines which are discussed within the article.
“the announcement that GSK is seeking licensure of the first generation malaria vaccine is a landmarkstep in our quest for a malaria vaccine. However it is important that the licensure of a partially efficacious malaria vaccine does not slow down development of more efficacious second generation vaccines and vaccines against vivax malaria.”
We eagerly await the outcome of GSK’s attempt to gain approval of RTS,S. Given the recent progress into the development of malaria vaccines, we hope the next few years will provide key advances in significantly reducing the death toll caused by malaria.
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