Researchers are hopeful they’ve moved one step closer toward realizing a long-sought dream of developing an effective vaccine for one of mankind’s most intractable afflictions, with US government approval for the testing of a new malaria vaccine. Dr. Stephen L. Hoffman, founder and chief executive officer of Sanaria Lab of Rockville, Maryland, thinks he’s found a solution for extracting the plasmodium falciparum parasite, the protozoan species that causes 99 percent of deaths of African children and adults who contract malaria, and transforming it into a workable vaccine. Dr. Hoffman says that Sanaria is hoping to begin trials among healthy adults in Africa next year to enable a vaccine to be developed, hopefully by 2015.
“What we’re reporting on now is that we’ve been able over the last five years at Sanaria to actually develop the manufacturing process that has allowed us to manufacture multiple clinical lots of the vaccine based on the whole parasite, one that we already know works and that we’ve been able to submit an investigational new drug application to the Food and Drug Administration, the FDA, and it’s passed.We’re quite excited that the vaccine that ‘couldn’t be made’ and the vaccine that would ‘never pass the FDA’ has now been manufactured multiple times and has passed the FDA and is now going to go into clinical trials,” he said.
For many years, scientists have known that people immunized by the bite of a weakened mosquito carrying the malaria parasite could become protected against malaria. By exposing the mosquito to a short period of irradiation, it would weaken the carrier, much like the methodology for developing vaccines against smallpox or polio. For years, the logistical problems of manufacturing such a vaccine have involved keeping mosquitoes bacteria-free, extracting the parasites out of their hosts, then purifying the infectious material, and putting it in vials and keeping the insects alive in weakened form while they are transported to Africa.Until recently, Dr. Hoffman points out that earlier attempts that focused on isolating and attacking specific genetic components of the parasite met limited success as the infection was extremely successful in changing its makeup becoming resistant to drugs.
“The farthest vaccine along is one that I began working on in 1984, and it’s been carried on initially by the Walter Reed Army Institute of Research, working all this time with what was then SmithKline Beckman, and now is GlaxoSmithKline Biologicals, and that vaccine gives on the order of 40-50 percent protection for a modest amount of time. It doesn’t prevent people from eventually getting malaria, but prolongs the time, so that the thought is that that vaccine may be able to reduce morbidity, meaning severity of illness, and maybe even death.And so we’re encouraged because there are results, just immunizing with that single protein, although it’s taken 25 years to even get to this point of that modest protection,” he explained.
Dr. Hoffman points out that malaria eradication has been a perpetuating struggle in tropical regions of the world, and vaccine development is but one part of a multi-pronged approach still very much needed for countries to keep up the fight.Last week’s observance of World Malaria Day on April 25, sponsored by the Roll Back Malaria Partnership succeeded in raising awareness and funds for time-honored conventional weapons to thwart proliferation – bednets,insecticides, better drugs for treatment and improved diagnostics.
“I think that the awareness has grown immeasurably over the last two, three, four years.The amount of funds that have been invested now in malaria control has increased perhaps ten-fold over the last five years, and we’re seeing a real impact in a number of places in the world, including sub-Saharan Africa, where infection rates are going down and disease is going down,” he noted.
In Africa, Ethiopia and Zambia have recently been cited as examples of sub-Saharan countries that have posted a 60 percent decline in their rates of infection over the past two years. While that achievement has not reached the zero-malaria benchmark that world health officials would like to envision for the year 2015, the prospect of one or more powerful vaccines by that time would go a long way toward ending untold suffering. But Dr. Hoffman still urges governments to temper their optimism with caution.
“The problem that I foresee for the future is sustaining that impact because malaria, if you let down your guard, comes back worse. There have been many times in a lot of these places where we’ve seen similar types of impact, and then the community lets down its guard.Resistance develops.Victory is declared.Then, all of a sudden, five years later, malaria is back, bad as it ever was, and perhaps worse. So the drive that is going on to control malaria now needs to be sustained, and that’s difficult,” he pointed out.
The biotech executive says the fight needs to continue for many years, but he says that if trials on the new vaccine enable widespread implementation of the inoculation strategy, it could prove to be a far-reaching intervention that would eliminate one million deaths a year and eradicate plasmodium falciparum from major portions of the planet.
