The world’s first human clinical trial for a treatment against the deadly Hendra virus is under way in Australia.
The treatment uses a human monoclonal antibody discovered by US federal scientists at the Uniformed Services University of the Health Sciences and the National Cancer Institute in Bethesda, Maryland.
It is not intended as a vaccine for the general population, but is expected to improve a person’s chance of survival should they come into contact with the virus.
The Hendra virus is carried by native Australian fruit bats. It is able to infect horses, probably through close contact with bat manure, urine, or birthing byproducts.
Since 1994, when the virus was first isolated, a total of 90 horses have died from the infection in 52 outbreak incidents, with 14 in New South Wales and 38 in Queensland.
During this period there have been seven confirmed cases of Hendra infection in humans, resulting in four deaths, all in Queensland.
All cases of human infection were believed to have resulted from contact with the bodily fluids of infected horses.
Approval for the human clinical trial was announced in Australia early in April, with healthy men and women aged 18 to 50 sought for the study.
To date, the monoclonal antibody-based treatment has only ever been used on compassionate grounds in 10 people – nine in Australia potentially exposed to the Hendra virus and one in the United States exposed to the related Nipah virus.
All survived, but there was insufficient information to determine whether the use of the treatment influenced this outcome, which is why further research was required.
The monoclonal antibody, known as m102.4, was isolated and characterised in work led by Christopher Broder, at the Uniformed Services University, and Dimitar Dimitrov, at the National Cancer Institute.
Antibodies – proteins found in blood or other bodily fluids of vertebrates – are used by the immune system to recognise and neutralise viruses and bacteria.
The m102.4 antibody attacks a critical component of the Hendra virus and blocks its ability to infect cells.
It was the world’s first antibody administered to humans as a treatment against Hendra virus infection, and was later also used to characterise a successful vaccine against Hendra in horses.
Experiments have shown that the antibody therapy is also effective against Nipah virus, a deadly pathogen which emerged in 1998 and has caused numerous outbreaks in Bangladesh, India, Malaysia and Singapore.
The Queensland Health department contracted the University of Queensland Australian Institute for Bioengeering and Nanotechnology, under director Professor Peter Gray, to manufacture the antibody for emergency stockpiles and for the human trial.
The institute has developed a way to produce large quantities of m102.4 without having to replicate any portion of the Hendra virus.
Broder said quite a number of people had worked on the development of the antibody therapy. It was rewarding to see the development of a therapy against pathogens such as Hendra and Nipah arising from basic science research, he said.