Tekmira expects to complete the Phase I clinical study later this year. Some scientists see the current West Africa outbreak of EVD as a unique opportunity to greatly advance the search for a cure and the vaccine is being stockpiled by the World Health Organisation (WHO) for use in emergencies.
“The primary objective of employing TKM-Ebola would be to further the clinical development of this agent,” says Dirk Haussecker, a biologist and medical consultant. “This outbreak is the best-case scenario to test this agent in actually infected patients with a side effect being that it would provide an incentive to people to be isolated.”
TKM-Ebola is not the only promising drug on the horizon. Several groups of biomedical researchers have already identified 150 or so neutralising antibodies against the Zaire strain of the virus, the strain responsible for the current outbreak. Some of these anti-Ebola virus antibodies have been used in cocktails and successfully administered to non-human primates. The monkeys survived in spite of being given lethal doses of EVD two days prior to being fed the cocktail.
While TKM-Ebola is a virus-specific drug that, so far, has limited broad-spectrum antiviral potential (most of the proposed Ebola treatments target a single strain of the virus) researchers at the USAMRIID and North Carolina-based BioCryst Pharmaceuticals have been working on a small molecule with broad antiviral activity.
The compound is called BCX4430 and it blocks the replication of RNA viruses like Ebola and Marburg. BCX4430 has been shown to protect primates against Marburg virus and shielded rodents from Marburg and Ebola virus infections. It has also been demonstrated to be effective against Yellow Fever virus infection.
“As it is becoming clear now, dying in isolation, surrounded by healthcare workers resembling aliens in space suits without the prospect of medical innovation is neither attractive to patients nor their families,” says Dirk Haussecker.
No wonder the relatives of some half dozen patients infected with EVD in Sierra Leone snatched their kin out from the isolation wards and, presumably, returned to their ancestral villages for better care. (Not surprisingly, one report said that the death toll in Sierra Leone doubled in a week.) Perhaps worse for the patient’s loved ones, is knowing that not everybody suspected of having Ebola has it and by putting them together with others that do, you expose them to it.
Then there is the issue of cost. Clinical trials are usually conducted in several phases that are very costly. According to Joseph Dimasi of the Tufts Center for the Study of Drug Development, the average cost of bringing a drug through trails is about $1.3bn.
Pharmaceutical companies are, first and foremost, businesses whose aim it is to turn a healthy profit and keep their shareholders happy. So the prospect of them financing a drug like TKM-Ebola for mainly rural Africans is a long shot.
Who will purchase it in sufficient quantities from the drug companies to make money? The financial incentive is simply not there for big pharma. Many observers, however, believe that it is within the capabilities of the US government to help fast- track drugs such as TKM-Ebola because of their heavy involvement in its development. British journalist Jessica Hatcher recently pointed out that the anti-malaria drug Mefloquine (Larium) was fast-tracked to the market thanks to the efforts of the US Defense Department and a pharmaceutical company (the military became involved because US troops contracted malaria during the Vietnam War).
However, as other experts have pointed out, such a strategy is not without its risks. Pharmaceutical companies are not allowed to use unlicensed drugs. Despite the validation thus far in monkeys, TKM-Ebola could still turn out to have more risks than benefits, and most would prefer to err on the side of caution.
But contrary to popular Western media images, Africans are not simply helpless victims of the EVD and other infectious and contagious diseases, but are proactive in stemming the spread of the disease at its onset.