As researchers around the world scramble to develop a vaccine to treat Zika, a group of Johns Hopkins scientists have found three existing drugs that show promise in treating the disease.
A team from the Johns Hopkins University School of Medicine joined researchers from Florida State University and the National Institutes of Health to test 6,000 existing drugs and their ability to stop or slow the virus.
They found three drugs, normally used to treat liver disease and parasitic worms, warranted further study because of the effectiveness in treating Zika in human neural cells grown in the lab, according to findings published Monday in the journal Nature Medicine. The drugs are either approved by the Food and Drug Administration or are being tested in final-stage clinical trials.
By testing drugs already on the market and proven to be safe, the scientists hope to speed up the research process for finding a way to combat Zika, a mosquito-borne virus spreading through the Americas that is linked to the debilitating birth defect microcephaly. Creating drugs from scratch takes longer and costs more.
"In the case of the Zika virus, there is urgency," said Hongjun Song, one of the researchers, who is also director of the Stem Cell Program in the Institute of Cell Engineering at Johns Hopkins. "We have to really shorten the process of drug development."
Research on repurposing drugs to treat other illnesses is emerging as a new tool to come up with quicker remedies for disease. Repurposing has led to potential treatments for diseases such as Ebola and hepatitis C. Large databases of medical information also have given scientists access to data to conduct such large-scale comparisons.
The drugs identified by the Johns Hopkins research would not eliminate the need for a vaccine, which would stop transmission of the disease.
The Center for Vaccine Development at the University of Maryland School of Medicine has said it will test a human vaccine by the end of the year. Johns Hopkins scientists and a private company started by Johns Hopkins affiliates also are working on a vaccine.
Researchers and public health officials are working aggressively to stop the spread of the Zika virus, which not only stunts the brains and skulls of fetuses in infected pregnant women but potentially causes other birth defects and has been connected to stillbirths and miscarriages.
There have been 77 cases of Zika in Maryland as of Aug. 24, all of them related to travel. Nationally, there have been 2,517 cases reported to the U.S. Centers for Disease Control and Prevention, including more than 40 attributed to local mosquito bites in Florida where the virus first hit the mainland United States. There have been 9,011 cases in U.S. territories, primarily in hard-hit Puerto Rico.
The Hopkins findings are the latest promising results that eventually could lead to treatment for Zika.
"Zika is a devastating illness, and the science is changing every day," said Baltimore Health Commissioner Dr. Leana Wen. "Every study makes us even more concerned about the impact of Zika on the future generation. If there is a medicine to reduce the effect on our most vulnerable unborn children, we need it. We need every available tool to prevent this disease and treat it."
Dr. Howard Haft, deputy secretary of public health services for the Maryland Department of Health and Mental Hygiene, said varied research can help lead to a solution to Zika.
"We all want to see an end to the scourge of Zika and to the birth defects it has been proven to cause," he said in a statement.
The promising drugs tested by the Hopkins researchers worked in two ways. They either prevented the virus from killing certain cells or prevented the virus from replicating.
In an earlier study, the researchers had discovered that Zika attacks specific stem cells that develop into neurons in the brain's cortex, which is associated with higher brain function.
Researchers at the University of Texas Medical Branch at Galveston also looked at how existing drugs can treat Zika. They screened 774 FDA-approved drugs to see if any of them could prevent Zika from infecting cells; they found 24 that could to some degree. The study results were published last month in journal Cell & Host Microbe.
"The idea was to identify drugs that are already out there that could be moved more quickly into clinical studies with people with Zika infections," said Shelton Bradrick, a co-author of the study.
The results of both the Hopkins and Texas studies are preliminary and need testing in animals and humans.
"We would need to go through clinical trials, but at least we shortened the process, and at least we know these drugs are safe," said Song, the Johns Hopkins researcher.
The Aedes aegypti mosquito has been the primary carrier and most efficient transmitter of Zika. Residents of Florida and other Southern states face the greatest risk of infection.
Maryland isn't likely to see many cases of local infection because the Aedes albopictus mosquito, also known as the Asian tiger mosquito, is more common in the state.
The FDA recommended last week that all donated blood and blood components be tested for Zika. The agency recommended that Maryland begin testing in 12 weeks.
Baltimore Sun reporter Meredith Cohn contributed to this article.