ATLANTA, Ga. — Scientists have developed a drug that could be an antiviral cure for both sexually transmitted infections and the COVID-19 pandemic.
In animal experiments, researchers discovered that a medication that mimics immune system proteins successfully treats herpes. The small synthetic molecule may also defeat the coronavirus and many other kinds of infections. The “stable peptoid” is harder to break down that the real thing.
The team suggests that doctors could give such a treatment to airline passengers before a flight to protect them from COVID. Scientists expect clinical trials to begin within months. Vaccines alone won’t overcome the pandemic, making anti-viral therapies are just as vital.
“In the body, antimicrobial peptides such as LL-37 help keep viruses, bacteria, fungi, cancer cells and even parasites under control,” says principal investigator Dr. Annelise Barron of Stanford University in a media release.
These substances are not usually ideal drug candidates as they are quickly cleared by enzymes in the body. With that in mind, study authors emulated the key biophysical attributes of LL-37.
“Peptoids are easy to make,” Barron says. “And unlike peptides, they’re not rapidly degraded by enzymes, so they could be used at a much lower dose.”
A better antiviral than the real thing
Herpes causes cold sores and oral or genital STIs (sexually transmitted infections). The peptoids safely prevented herpes infections in mice when dabbed on their lips. Earlier tests on human cells grown in lab dishes showed the compounds also deactivated SARS-CoV-2 and HSV-1 — the viruses that cause COVID and herpes, respectively.
Scientists also designed the drugs to be non-toxic to people. They are simple and inexpensive to make with an automated synthesizer and readily available chemicals.
“You can make them almost as easily as you make bread in a bread machine,” the Stanford researcher adds.
Peptides consist of short sequences of amino acids, with side chains bonded to carbon atoms in the molecules’ backbone. This structure is easily broken apart by enzymes. In peptoids, the side chains are instead linked to nitrogens in the molecular backbone, forming a structure that resists enzymes.
The researchers are planning to test them for activity against SARS-CoV-2 in mice. The team also founded the company Maxwell Biosciences to develop peptoids as clinical candidates to prevent or treat viral infections.
“COVID-19 infection involves the whole body, once somebody gets really sick with it, so we will do this test intravenously, as well as looking at delivery to the lungs,” Dr. Barron explains.
Could peptoids be a wide-ranging cure-all?
Additional experiments are now underway to confirm the mouse findings. In addition, the peptoids could be effective against HSV-1 drug-resistant strains. The antimicrobial molecules could have a host of applications. Work is ongoing at Stanford to explore their impact on ear and lung infections. Dr. Barron’s team has sent peptoid samples to experts in other labs to test against a range of viruses. There have been promising results in lab dish studies against influenza, the cold virus, and hepatitis B and C.
“In their in vitro studies, a team found that two of the peptoids were the most potent antivirals ever identified against MERS and older SARS coronaviruses,” Dr. Barron says.
Other labs are testing the peptoids as anti-fungals for airways, the gut, and as anti-infective coatings for contact lenses, catheters, and implanted hip and knee joints. The researchers are studying how these broad-spectrum compounds work. The study notes that such antivirals seem to pierce and break up the viral envelope and also bind to the virus’ DNA.
That multipronged mechanism has the advantage of inactivating the virus. Standard antivirals slow replication but still allow viruses to infect cells. It also makes it less likely that pathogens could develop resistance.
The team presented their findings at the American Chemical Society virtual meeting ACS Fall 2021.
South West News Service writer Mark Waghorn contributed to this report.