University of Georgia

University of Georgia

Researchers to test drug candidates to treat malaria

University of Georgia researcher Belen Cassera
Belen Cassera will lead a research team that will test two new drugs for the treatment of malaria. The team’s work will be funded by a $3.7 million grant from the National Institutes of Health. (Photo by Amy Ware)

Though malaria was eliminated from the U.S. 70 years ago, the mosquito-borne disease caused by the Plasmodium parasite is still rampant in many parts of the world—nearly 40% of the world’s population is at risk of contracting it, and nearly 450,000 people die each year from it. With the rise of drug resistance, the current medical treatments aren’t enough to end this disease.

“Every drug treatment currently in use for malaria is showing resistance or reduced efficacy,” said Belen Cassera, a member of the University of Georgia’s Center for Tropical and Emerging Global Diseases. “Furthermore, there are very limited treatments for the most vulnerable—children and pregnant women. Over 60% of deaths are children under the age of 5.”

Cassera is co-leading the research team that recently received a $3.7 million grant from the National Institutes of Health to test two new drug candidates.

“These compounds are really promising as they are easy to synthesize, cheap, reliable, have a low toxicity profile, and kill the parasites fast,” said Cassera, associate professor in the Department of Biochemistry and Molecular Biology, part of the Franklin College of Arts and Sciences.

What’s unique about these compounds is that they can kill the parasite in three developmental stages in humans. Current treatments only target the blood stage, which is when clinical symptoms appear.

The life cycle of the Plasmodium parasite is complex. When an infected mosquito bites a person, just a small number of parasites—usually less than a hundred—are injected into the bite site and then travel to the liver, where they multiply into the thousands. Once their numbers are sufficient, they invade the bloodstream and infect red blood cells.

When the number of parasites reaches 100 million, symptoms occur and some of the parasites develop into a sexual form, also known as the gametocyte stage. The sexual form is then transmitted back to the mosquito when the person is bitten again.

This complex life cycle makes it difficult to find a treatment that will eradicate the disease. Breaking the cycle of transmission between humans and mosquitos is key to accomplishing that goal. That’s why the team is excited about discovering compounds that can attack the parasite on multiple fronts.

“We are really a powerhouse team,” said Cassera. “We have a leading medicinal chemistry expert in Paul Carlier, the robust parasitology resources of UGA, and Max Totrov brings the machine-learning expertise to tie it all together.”

Cassera is a UGA Innovation Fellow, and she credits the knowledge gained at UGA’s 2019 Innovation Bootcamp with helping her prepare a grant proposal that would be of particular interest to drug manufacturers.

Cassera has been working for several years to identify new drug candidates, along with Carlier, a professor in the Virginia Tech College of Science’s Department of Chemistry and director of the Virginia Tech Center for Drug Discovery, and Max Totrov, a computational chemist at Molsoft.

“We started working with the Malaria Box from Medicines for Malaria Venture, and the discoveries we made in basic malaria biochemistry and medicinal chemistry really springboarded us to a new level and led us in this new direction,” Cassera said.

Cassera is leading the testing of new chemical variations of the antimalarial compounds prepared by Carlier for effectiveness in cellular and animal models.

“My lab will be looking at levels of toxicity, the potential for resistance, and how well they work both directly on the parasite and in infected mice,” she said. “We’ll be performing the studies for making the go/no-go decision for these compounds.”

A joint patent application for both drug candidates was recently filed, and the team is optimistic that their research will yield fast-acting candidates for advanced pre-clinical evaluation.