A Minnesota company working on what could become the nation's first drug made of microbes from the human gut has been snapped up by a large Swiss drugmaker.

Rebiotix, a biotech startup based in Roseville, was acquired by Ferring Pharmaceuticals in a deal that closed Wednesday. The private companies declined to disclose the price.

Although Rebiotix is closer than any other company to securing Food and Drug Administration approval for a drug that contains human gut microbes, Ferring executives are just as interested in long-term drug projects using Rebiotix' proprietary platform.

"Rebiotix is basically a full-fledged biotechnology company with their own platform," Ferring Chief Scientific Officer Per Falk said Wednesday. "We're of course extremely interested in the forerunner products ... However, we actually see it as the acquisition of a platform."

Rebiotix will retain its name and its 45 employees, including CEO Lee Jones. Ferring doesn't plan to disrupt Rebiotix' operations with location changes. "It has been established here, the knowledge is here, and we cannot afford to risk that," Falk said in an interview in Roseville.

Ferring, which styles itself a research-driven pharmaceutical company, sells a variety of drugs for reproductive and women's health, urology and gastroenterology. Based in Switzerland, the company has U.S. headquarters and manufacturing operations in New Jersey and a major research center in San Diego. It had $2.4 billion in revenue last year, much of that from its most popular drug, the injectable fertility therapy Menopur.

Rebiotix, meanwhile, is a leading contender to be first-to-market with a closely watched drug that can treat deadly infections of Clostridium difficile, or "C. diff" using gut microbes extracted from human feces.

C. diff represents a major public health problem in the U.S. The Centers for Disease Control and Prevention said C. diff microbes colonize the intestinal tracts of more than 500,000 people per year in the U.S. In 2011, an estimated 29,000 of them died within 30 days of contracting C. diff infections, according to a 2015 article in the New England Journal of Medicine.

C. diff infections can be pernicious because the most common treatment is also the likely cause: powerful antibiotics.

The human gut is home to a zoo of microbial life that processes food and interacts with the immune system. Normally these microbes exist in a balanced ecosystem, but researchers believe that powerful antibiotics can wipe out certain natural bacteria, giving opportunistic microbes like C. diff the chance to overpopulate the dark and twisty environment known as the "gut microbiome."

Having too many C. diff microbes there can induce severe diarrhea, dehydration, kidney problems, and bowel perforation.

The most common treatment for the condition is to take more antibiotics, like vancomycin. But about 25 percent of these patients will have another recurrence of C. diff infection, usually within 30 days, and studies have shown that the risk of reinfection more than doubles after two or more recurrences, according to a 2012 article in the journal Clinical Microbiology and Infection.

Gut doctors at places like the University of Minnesota and the Mayo Clinic can transplant microbes from a healthy person's gut into a C. diff patient, which has been shown in small studies to cure many recurring C. diff infections. A U study published in the Journal of Gastroenterology last year reported an 88 percent success rate after two months in 49 patients with no serious adverse events.

Several companies are also working on proprietary methods to create standardized treatments that could garner FDA approval as a drug, and Rebiotix is the furthest along in its efforts.

Rebiotix is in the third and final phase of clinical trials for the Food and Drug Administration in treating recurrent C. diff using a drug formulation called RBX2660, which delivers microbes from a healthy person's stool into a C. diff patient. RBX2660 has been accepted into several FDA programs intended to speed up reviews for much-needed novel drugs.

It's also in early testing for vancomycin-resistant enterococci, pediatric ulcerative colitis and multi-drug resistant urinary tract infections.

A related compound is also being tested for recurrent C. diff.

Both compounds are created using Rebiotix' Microbiota Restoration Therapy platform, the proprietary system of delivering live, human-derived microbes into a patient's intestinal tract. Rebiotix said the platform may lead to the creation of "an entirely new category of drugs" that could treat conditions like ulcerative colitis, hepatic encephalopathy, and other infectious, metabolic, liver, inflammatory, and neurological diseases.

"My personal belief is that I think it could change the face of medicine," Jones, the Rebiotix CEO, said.

Joe Carlson • 612-673-4779