Based on promising results in an early clinical trial, Mayo Clinic has formed a new joint venture with materials engineering firm W.L. Gore & Associates to spearhead a new therapy using stem cells to repair a painful tissue problem stemming from Crohn's disease.

Mayo and Gore on Tuesday announced the formation of a for-profit company called Avobis Bio ("a vobis" is Latin for "by you"), based in Delaware, where Gore is also based. The privately held company will draw on the expertise of scientists at Mayo and Gore to launch a second-phase clinical trial in the hopes of eventually offering the treatment commercially.

A laboratory director at Mayo Clinic said Avobis Bio's therapy, if successful, may be a first-of-its-kind in health care, involving the delivery of a person's own mesenchymal stem cells on a synthetic "scaffold" that biodegrades over time, eventually leaving behind only native tissue sealing a wound. The first application of the technology is treatment of a health problem called perianal fistulae. But if successful, Avobis Bio may one day offer a variety of tissue and organ-repair therapies combining Mayo's stem cell expertise and Gore's medical materials.

"This is a completely new approach, where we are trying to leverage what the body can do for itself," said Allan Dietz, co-director of the Human Cell Therapy Lab in Mayo's Center for Regenerative Medicine.

Mesenchymal stem cells can naturally convert into other kinds of tissue, like muscle or bone. For the Avobis Bio therapy, the cells are harvested from a biopsy of a person's body fat and cultivated at a Mayo laboratory to high purity. No one knows whether the cells deposited into the wound directly convert into scar tissue, or if the stem cells trigger genetic signals that cause other cells in the surrounding tissue to begin the healing process.

"We provide stem cells in the right frame, at the right time, for the body to recognize the signals that it should begin the healing process," Dietz said. "I think in some ways, it was a required simple first step … but it appears to be a major step."

Gore is perhaps best known to the public for its Gore-Tex outerwear, but the privately held $3.7 billion engineering and manufacturing firm sells products in an array of industries, including a line of medical devices designed to repair nonnatural holes in body organs. Mayo has used Gore-made devices for many years.

Several years ago, physician-researchers at the not-for-profit Mayo Clinic in Rochester grew keenly interested in a Gore device called the Bio-A Fistula Plug, a flexible bioabsorbable plug made from a material similar to dissolving stitches.

The plug can be used to repair unnatural canals that form between a person's anal canal and their outer skin, after Crohn's disease weakens surrounding tissues. These canals, also known as perianal fistulae, are painful, disruptive and difficult to treat, doctors said. For patients with Crohn's disease, lifetime incidence of perianal fistulae ranges between 23% and 38%, according to past studies.

In 2017, Mayo announced first-in-human results of their experimental therapy treating Crohn's patients' perianal fistulae using a Gore Bio-A Fistula Plug coated with the patient's own stem cells. The study, run in consultation with the Food and Drug Administration, provided the open-label treatment to a small group of patients whose fistulae had not responded to treatment for a median time of six years.

After initial results proved encouraging, the trial eventually enrolled 20 people. Of the 19 who remained in the trial for at least a year, 76% experienced healing of their fistulae, according to results announced by researchers but not yet published in a journal. If validated in a larger clinical trial, that rate of healing would be dramatically better than outcomes under existing treatments, the companies said.

"We have done work in the past looking at combining cells and materials. For us, the clinical trial results from Mayo were incredibly compelling," said Tiffany Brown, a Gore employee and general manager of Avobis Bio. "It is a challenge to translate how cells behave in the lab to how they will behave in patients. So having that proof in real patients really got the conversation going on how we could work together."

If the therapy is proved safe and effective in larger trials, Brown said about 50,000 Crohn's patients per year could be eligible to get it for perianal fistulae. Although Gore is phasing out general sales of its Bio-A Fistula Plug, the device will be supplied exclusively to Avobis Bio.

Mayo and Gore declined to reveal financial details for Avobis Bio, except to note that both parties are contributing to the limited-liability joint venture. The company has a five-member board of managers, with Mayo appointing two members and Gore appointing three.

Joe Carlson • 612-673-4779