• Posted May 15, 2024

Early Hints at a Gene Therapy Cure for Herpes

An experimental gene therapy could one day provide a first-ever cure for genital and oral herpes, researchers report.

The gene therapy removed 90% or more of oral herpes infection in lab mice, and it also suppressed how much virus an infected animal shed, according to results published May 13 in the journal Nature Communications.

The experimental therapy involves an injection of gene-editing molecules that seek out herpes virus hiding in the body, researchers said.

"Herpes is very sneaky. It hides out among nerve cells and then reawakens and causes painful skin blisters,"explained researcher Dr. Keith Jerome, a professor in the Vaccine and Infectious Disease Division at Fred Hutch Cancer Center in Seattle.

The gene-editing cocktail includes laboratory-modified delivery viruses that contain an enzyme that works like "molecular scissors,"the researchers said.

Once the delivery virus reaches a cluster of nerves where herpes is hiding, it releases the enzyme. The enzyme then snips away at the herpes virus's genes, to either damage or destroy it.

The enzyme "cuts in two different places in the herpes virus's DNA,"said lead researcher Martine Albert, a principal staff scientist at Fred Hutch. "These cuts damage the virus so much that it can't repair itself. Then the body's own repair systems recognize the damaged DNA as foreign and get rid of it."

An estimated 3.7 billion people younger than 50 have herpes simplex virus 1, which causes oral herpes, according to the World Health Organization.

Another 491 million people 15 to 49 have herpes simplex 2, which causes genital herpes.

This experimental therapy eliminated 90% of facial infection and 97% of genital infection in lab mice who were infected with herpes simplex 1, researchers say.

It took about a month for the treated mice to reach these reductions, and the reduction of virus appeared to become more complete over time.

"If you talk to people living with herpes, many are worried about whether their infection will transmit to others,"Jerome said in a cancer center news release. "Our new study shows that we can reduce both the amount of virus within the body and how much virus is shed."

This new therapy represents a streamlined approach to attacking herpes.

In a 2020 study, the research team used three different delivery viruses armed with two different enzymes to attack herpes. This study used just one delivery virus and one enzyme capable of cutting the virus DNA in two places.

"Our streamlined gene-editing approach is effective at eliminating the herpes virus and has less side effects to the liver and nerves,"Jerome said. "This suggests that the therapy will be safer for people and easier to make, since it has fewer ingredients."

Researchers are preparing to translate the findings into treatments for humans that can be tested in clinical trials.

"We're collaborating with numerous partners as we approach clinical trials so we align with federal regulators to ensure safety and effectiveness of the gene therapy,"Jerome said.

The team also is adapting the gene-editing technology to target herpes simplex 2 viruses.

More information

The Cleveland Clinic has more about herpes simplex.

SOURCE: Fred Hutch Cancer Center, news release, May 13, 2024