Eliminating malaria

RBWH Infectious Diseases specialist Professor James McCarthy heads the team using a human challenge model to test new drugs on live malaria parasites inside the bodies of human volunteers. The work is supported by the Medicines for Malaria Venture, with funding from the Bill and Melinda Gates Foundation, as well as from the NHMRC.

Professor McCarthy’s team first collected malaria parasites from patients in the RBWH infectious diseases ward. These parasites are stored in freezers until they
are injected into human volunteers at Q-Pharm. These volunteers are then monitored until their parasite load is just high enough to test the new drugs, but before they develop malaria symptoms.

“We use a very sensitive type of DNA test to detect the malaria about a week before the patient gets sick,” Professor McCarthy says. “Once the blood has reached
the target parasitaemia, we try the new drugs. If they don’t work, we treat with a drug we know works.”

Malaria is a risk for half the world’s population. More than 200 million people are infected and around 400,000 die each year. Professor McCarthy is the world
expert in this research field. Already the team has tested nine new drugs this way, with another two planned in 2017. Five of the drugs he has tested on the Herston Campus are now in advanced stages of clinical trial, and on a path to market.

“Our human challenge method is protecting kids in Africa from experimental drugs not working,” Professor McCarthy says. “This way of testing is much better than all alternatives, as the other ways are very slow and much more expensive. We’re speeding up access to safe treatments.”

Once the volunteers have reached the target parasite level in their blood, they’re admitted to Q-Pharm, a specialised clinical trial company within QIMR Berghofer, while they’re treated. As Brisbane does not have malaria mosquitos, the volunteers cannot transmit malaria to others. Nevertheless, the volunteers remain inpatients at Q-Pharm for three days until they are definitely clear of malaria.

One critical outcome of research, Professor McCarthy believes, should be training the next generation of doctors to do clinical research. His registrar John Woodford, working at the Herston Imaging Research Facility (HIRF), is engaged in a world-leading study using PET-MRI scanning before and after infection with malaria to track where the parasite travels in the body and study its effects on vital organs in real time.

“We’re doing the first ever in vivo imaging of human malaria,” Professor McCarthy says. “It’s only possible because we have HIRF on site.”

The research includes transmission studies as well, testing whether the drug prevents the infected patients from passing malaria to mosquitos, using malaria
mosquitos held in a secure facility at QIMR Berghofer. Professor McCarthy is also working with partners in Melbourne to develop a vaccine, using a genetically
modified malaria parasite to protect against the disease.

“As the number of infected people declines, and as resistance increases, we need new tools to get rid of malaria,” he says. “The global goal is to eliminate
malaria by 2030, so we need more drugs, diagnostics and vaccines.”

The team is supported by a $10 million grant from the Gates Foundation through the international Medicines for Malaria Venture.

Professor McCarthy also leads a team of nine researchers from across Australia looking at parasitic diseases including malaria, worms, and streptococcus A. The
group has recently received a $19 million NHMRC Program Grant to support research over the next five years.