If there are to be vaccines and drugs against Ebola, trials in outbreaks will have to be done
In 2002, scientists writing in a leading American medical journal discussed the possibility that the Ebola virus could be used in a biochemical weapon. It would be technically difficult and unlikely to cause mass destruction because those infected quickly die and the virus is not as transmissible as many assume. But, the scientists warned, if it could be done, there would be no protection. No vaccine or drug treatment exists.
They were writing in the Journal of the American Medical Association in the wake of 9/11 and the subsequent anthrax attacks in New York. Since then, fear of viruses raining out of US skies has diminished – and so has any sense of urgency over the development of vaccines or treatment for a disease that manifests itself in unpredictable outbreaks and kills relatively small numbers of people in remote parts of Africa.
Neglected tropical diseases, of which Ebola is one, become visible in the west only when they appear to threaten it. Ebola has had more attention than many, probably because of the dramatic nature of the disease and the need for full body suits and face masks for those caring for its victims. The names of other such diseases – the parasitic leishmaniasis and lymphatic filariasis, for example – hardly trip off the tongue in London or San Francisco.
Yet Ebola is not a priority for the not-for-profit Drugs for Neglected Diseases Initiative, which works with the World Health Organisation and others to incentivise and encourage pharmaceutical companies to research and develop treatments. It affects far fewer people than parasitic diseases, and the outbreaks, although appalling, are sporadic.
But in a few research institutes and biotech companies in north America, there is work going on, some of it funded by the American military. The US department of defence Joint Project Manager Medical Countermeasure Systems has put $140m (£80m) into the early development of a potential drug by the Tekmira Pharmaceuticals Corporation, which dosed its first human subject in January this year. The phase 1 trial is designed only to ensure the drug has no ill effects in healthy people who have been nowhere near the Ebola virus, but last week, it was put on hold while the regulator, the food and drug administration, asked for more information to ensure the safety of the volunteers.
There were protests over the FDA’s intervention and calls for the drug to be fast-tracked, since more than 600 people in west Africa had already died. But even if the FDA felt it was a good idea to test the drug on patients in Africa, trials in humans take so long to set up that the current outbreak will probably be over by the time anybody is ready.
There are some vaccines in development which look promising. “Many of them have just been tested in mice and guinea pigs, but a few have been tested in non-human primates and worked, protecting them from challenge with the virus,” said Professor Diane Griffin from Johns Hopkins Bloomberg School of Public Health in Baltimore.
But however great the need, rushing the vaccine to an outbreak of Ebola in west Africa is not on the cards. “I think people are really anxious just because the vaccines haven’t been tested in humans for safety as far as I know,” said Griffin, of the department of molecular microbiology and immunology at the school’s centre for global health.
Running a trial in the middle of a disease outbreak is really difficult too, because of the careful explanation that must be given to all those who are vaccinated – and those who are not – who are in a distressing situation. Potential side-effects must be talked through and informed consent given.
Pfizer’s attempt to trial an oral antibiotic during a meningitis B outbreak in Kano, Nigeria, in 1996 ended in disaster for the company, which was sued by families who blamed the drug for deaths. It paid millions in compensation.
But if there are to be vaccines and drugs against Ebola, trials in outbreaks will have to be done. “It would be unethical not to acknowledge that potential new treatments could both save lives and reduce transmission in this and future outbreaks,” says Professor Jeremy Farrar, director of the Wellcome Trust. “Is it time to fast track those with clear safety data in humans for use in this epidemic?”
He believes it is essential for those with promising drugs or vaccines to be ready to go. They must have done all the preparatory work, the early testing and safety checks, have got the approval of ethical and regulatory bodies and have local and national governments as well as NGOs in the field such as Medecines Sans Frontieres on board.
“It is a complex situation, requiring very careful consideration,” Farrar says. But ultimately, the only way to find out if drugs and vaccines against Ebola work is to try them out in an epidemic.
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