Ring Therapeutics Launches to Expand Gene Therapy Viral Vector Options

Xconomy Boston — 

Ring Therapeutics, a Flagship Pioneering spinout, launched Thursday with ambitious plans to expand the universe of vectors available for gene therapy delivery.

Gene therapy, treatments intended to treat disease by inserting a gene instead of using drugs or surgery, has had a banner year, with the second ever such therapy approved this year in the US.

Ring want to use its research into viruses that exist in the human body without apparent negative effects to provide more and better options to fuel the rise of gene therapy treatments.

For the past two years, Flagship Pioneering partner and Ring’s founding CEO Avak Kahvejian says the company has been exploring the human commensal virome—basically, a group of viruses that exist within humans without negative effects—for its potential to address limitations of the vectors currently used.

The sector relies heavily on adeno-associated viruses (AAVs), which naturally infect humans but aren’t known to cause disease, to deliver the DNA. Previous exposure, however, can spark an immune response.

“A lot of the workhouses in gene therapy have either been pathogenic viruses or viruses that have been taken from other species or viruses that are highly immunogenic, or all of the above,”  Kahvejian tells Xconomy. “That leads to a certain number of limitations, despite the successes and advances we’ve made to date.”

A number of issues stymie widespread use of AAVs, Kahvejian says, including the fact that 10 percent to 20 percent of people have at one time or another been infected with such a virus, thereby building up an immune response to it. Another concern is where such gene therapies end up, because viruses tend to gravitate toward certain types of tissues, and to go elsewhere, require special tweaking.

The Cambridge, MA-based startup believes the viruses it has found are unlikely to cause an immune response or prove pathogenic, given their ubiquity in the body.

Like extrachromosomal DNA—a new discovery at least one company is exploring for its potential as a target in cancer treatments—the viral sequencing Ring is studying are circular pieces of DNA that exist outside the 23 chromosomes of the human genome.

Ring says it has found thousands of these viruses that coexist with our immune system. It aims to use those to develop vectors that can facilitate gene replacement throughout the body—multiple times, if necessary. While gene therapy is thought of as a one-time fix, cell turnover means whatever the “fix” engendered by the inserted gene could falter over time, necessitating a re-up.

Kahvejian wouldn’t share a timeline for Ring’s plan to develop re-dosable, tissue-targeted treatments.

“We’re looking at the unique features and activities of these viruses in different tissues to establish the various vectors we’re going to pursue,” he said.

Flagship, which pursues scientific questions in-house and builds and funds companies around the answers—has put $50 million toward Ring, which has about 30 employees.

Ring’s president is Rahul Singhvi, an operating partner at Flagship. Most recently he was chief operating officer of Takeda’s global vaccine business unit. Its head of R&D is Roger Hajjar, who has led gene therapy trials in patients with heart failure.

Ring is the second startup Flagship has spun out this month. Cellarity launched last week.