Developing an effective malaria vaccine is a top priority among public health officials. Despite four decades of rigorous work, this goal remains elusive.
Malaria, caused by a mosquito-borne parasite, reportedly kills almost 500,000 children a year, and in 2012 there were 207 million cases of malaria according to the WHO. With the prevalence of this disease expected to increase in coming years due in part to rising global temperatures, the race is on to develop the first generation of commercially available vaccines for this disease.
Technological challenges have scuttled development of an effective vaccine
Vaccines have been one of mankind's best weapons against infectious diseases. Most vaccines act against viruses or bacteria that tend to elicit well-defined immune responses, giving researchers a clear therapeutic goal. Malaria, by contrast, is caused by a protozoan that has a complex life cycle, creating unique challenges in the development of a vaccine.
Researchers have developed several malaria vaccines in the past, with only GlaxoSmithKline's (NYSE:GSK) RTS,S showing much promise. In a recent late-stage trial looking at RTS,S' ability to block malaria infections in over 15,000 children across seven countries, the vaccine reportedly halved the number of infant infections expected without immunization.
While that is still a far cry from a broadly effective vaccine, Glaxo believes it's sufficient for a regulatory filing with the European Medicines Agency, or EMA, given the complete lack of alternatives. A regulatory filing with the EMA is thus expected by the end of 2014, with a potential commercial launch by 2015. Put simply, we are on the verge of having the first commercially available malaria vaccine -- the culmination of decades of work.
A recent scientific breakthrough may hold the key to a functional cure
Although Glaxo's progress in this area shouldn't be marginalized, scientists are already looking for more effective ways to combat this disease. And they may have found it.
Dr. Jonathan Kurtis, a pathology and laboratory medicine professor at Brown University, discovered a parasite protein that enables the malarial parasite to escape from red blood cells and thus spread within the body. An obvious therapeutic goal would be to develop a vaccine using this protein as a means of blocking the parasite's ability to escape in the first place.
Kurtis is reportedly conducting preclinical studies in animals of an early version of a vaccine based on this insight, with the goal of eventually testing it in humans. That said, we are probably years away from a commercially available vaccine that could employ this technology.
Malaria is undoubtedly a top public health concern, especially in tropical countries. We are presently limited to controlling mosquito populations through the use of chemicals that may have long-term health and environmental consequences. As such, there has been a long-held desire to develop a vaccine to help combat this widespread disease. Unfortunately, the parasite's complex biology has repeatedly thwarted the best efforts.
The potential commercial launch of Glaxo's RTS,S may be the tipping point in the field, however. That being said, you shouldn't expect this vaccine to have much impact on Glaxo's top-line growth, as it was developed primarily for humanitarian purposes with the support of the Bill and Melinda Gates Foundation, as well as the nonprofit PATH Malaria Vaccine Initiative, or MVI. Glaxo is reportedly only going to receive a 5% margin on any sales of RTS,S, and even that money is slated to be reinvested in further malarial research.
Looking ahead, the developmental-stage vaccine makers Inovio Pharmaceuticals and Novavax have reportedly picked up the torch in the efforts to develop the second generation of malaria vaccines. Even so, this work has petered out to some degree, presumably because of the high financial risks combined with the low commercial rewards associated with developing vaccines for malaria.
For example, Inovio was reportedly working on two synthetic multiantigen DNA vaccines using funding from MVI, but this program has yet to progress to human testing despite preclinical work wrapping up some time ago. In 2012, we learned that Novavax was interested in working on a recombinant malarial vaccine using funding from the Indian government, but the company hasn't provided an update on this effort in well over a year.
Kurtis' recent work may help to reignite interest among pharma companies in pursuing an effective malaria vaccine now that a novel therapeutic target has been discovered. Time will tell.