Seres Therapeutics, a microbiome-based biopharmaceutical company in Cambridge, Mass., is developing a pill, subject to a rigorous approval process under the Food and Drug Administration, to tackle recurrent Clostridium difficile. (The digestive system's microbiome is the community of healthy gut bacteria that normally reside in the body.) Half a million people a year are infected with C. diff in the U.S., the CDC estimates, with 29,000 annual deaths related to the diarrheic bacterium. More than 65 percent of C. diff infections involve exposure in a health-care facility, according to a 2015 study, creating more than $4.8 billion in excess health-care costs at acute-care facilities alone.
Seres aims to put the science behind a proven treatment of recurrent C. diff, fecal transplants, in a pill, which wouldn't require a colonoscopy. Like probiotic supplements, it’s a gut bacteria product. Unlike the supplements, by the time it’s available it will have gone through the FDA wringer. It will contain about 50 strains of bacteria proven effective in treating C. diff and will require a doctor's prescription.
Recurrent C. diff is an obvious entry point for Seres, said Chief Executive Officer Roger Pomerantz. “We asked, what is the lowest-hanging fruit?” But it’s hardly the end. The company has built a microbiome library of 14,000 strains of human bacteria it hopes will help it treat a range of diseases, eventually without needing feces at all.
Seres has embarked on the research with some pretty lofty goals, including finding treatments for obesity, liver disease, and cancer. It has partnerships with Massachusetts General Hospital, the Mayo Clinic, Memorial Sloan Kettering Cancer Center, and other respected medical institutions.
Another top contender is Rebiotix. Its RBX2660 is also designed to treat recurrent C. diff but, unlike SER-109, is administered with an enema; an oral version is in development. The treatment also differs significantly from Seres's in formulation, including thousands of kinds of microbes from the donor’s stool, compared with SER-109's 50 or so, as many as could be preserved and some of which haven’t even been identified.
“We make sure we have a minimum concentration of certain kinds that we know the patients lack,” CEO Lee Jones said. “But we don’t identify all of them. There’s no way to do that.” A recent study estimated that 1014 bacteria are in the human gut, most of which have never been isolated. Jones said the drug could hit the market by 2018.
The medications have been shown to be similarly effective—with no C. diff-associated diarrhea for 29 of 30 of Seres's patients and 27 of 31 of Rebiotix's, in the companies' latest results—and equally safe. Adverse reactions for both are limited to such problems as moderate diarrhea and abdominal cramping, which could be from the C. diff itself. Both have been designated as "breakthrough therapies" by the FDA, allowing for an expedited approval process, and both are likely soon to provide an at-home alternative to fecal transplants.
Seres does have at least one distinct market advantage. “Patients have different preferences,” Hecht observes, but “in general, people don’t particularly like enemas.”
SOURCES - Bloomberg, Seres Therapeutics