Two people got very sick, and one died, during a trial of an experimental procedure known as fecal transplant, according to a statement issued Thursday from the Food and Drug Administration. As a result, the agency is suspending several clinical trials investigating the procedure until safety standards can be assured.
Researchers are studying fecal microbiota for transplantation, or FMT, as a treatment for several intestinal conditions, including recurrent, antibiotic-resistant Clostridium difficile infection, which led to 29,000 deaths in 2015. FMT, which involves transplanting stool from a healthy person into the colon of a sick person, is still not approved by the FDA.
This week's case involved two immuno-compromised adults who received investigational fecal transplants that contained a strain of antibiotic-resistant E. coli, according to the FDA. Both individuals received stool from the same donor, who was not screened for disease-causing bacteria before the procedure.
While the FDA does not currently approve FMT for any use, the agency provides some guidelines for clinical trials of FMT, and seeks "to strike a balance between assuring patient safety and facilitating access to unapproved treatments for unmet medical needs," said Dr. Peter Marks, director of FDA's Center for Biologics Evaluation and Research, in the FDA statement.
In response to these adverse outcomes, the FDA announced new standards requiring researchers in clinical trials to demonstrate proper screening procedures for donor stool.
"This case is really unfortunate," says Dr. Dale Gerding, a researcher at the Veterans Administration who consults on a number of FMT trials currently under review by the FDA. "I think it reinforces the need for FDA oversight over FMT. It's exceedingly useful some patients, but we need to be sure that it's safe."
Fecal transplants have been successful in treating C. difficile infections in several trials.
According to Gerding, recurrent bouts of C. difficile infection likely stem from an abnormal intestinal microbiome that allows C. difficile to multiply unabated by "good" bacteria. Recurrent bouts of the infection are also increasingly resistant to antibiotics, leaving patients with few options.
Fecal transplants from a healthy individual can normalize the patients' microbiota, quelling the infection and relieving symptoms. Studies show that it works better than other treatments for recurrent infection. "Anywhere from 75 to 90 percent of patients no longer have recurrent cases after a single FMT," says Gerding.
But despite its success, Gerding cautions that there are still many unknowns. "FMT is very promising, especially for C. difficile infection, but we don't know as much about how effective it's going to be for other diseases like inflammatory bowel disease," he says. Despite these unknowns, interest in FMT is surging, with some patients taking a do-it-yourself approach.
Gerding hopes this recent case will underline the need for enforcement of safe procedures. "This death is the most extreme side effect I'm aware of in the history of FMT," says Gerding. "Moving forward we have to clearly be sure that we're enforcing safety measures that ensure that donors are tested for potential pathogens."
Jonathan Lambert is a freelance science journalist based in Washington, D.C. You can follow him on Twitter: @evolambert