The disease your family member may be able to cure
C difficile is a debilitating intestinal infection that causes some people to have recurring hospital visits. Others are trapped in their homes afraid to leave for fear of embarrassing themselves. The illness creates toxins that lead to abdominal pain and persistent watery diarrhea.
Gastroenterologist David Guo, MD, PhD, at Falmouth Specialty Care has one patient who is so frightened of having a recurrence of C difficile, she refuses to ever take antibiotics again.
“After the C difficile is gone you can still have irritable bowel syndrome,” Dr. Guo explained. “It’s not as bad as C diff but sometimes you can have many more bowel movements in a day. She is so scared of those days.”
Millions of different bacteria live in our intestines. Most are helpful, the so-called “good bacteria,” that create gut health and protect us from infection. But, when you take an antibiotic, the good bacteria can be killed, leaving a welcoming environment for bad bacteria to proliferate. One of the most dangerous bacteria is Clostridium difficile, also called C difficile or C diff, explained Dr. Guo.
The number of people with C diff infections has risen at alarming rates in recent years. Almost a half a million people were infected and about 29,000 people died from C diff in 2011, according to a study funded by Centers for Disease Control and Prevention. It was the largest longitudinal study of C diff in the United States to date.
“We think the increase is related to the wide use of antibiotics,” Dr. Guo said. “It’s not only more prevalent, but there are certain strains that are more vicious and can kill people.”
A Growing Problem
According to the CDC, one in five people experience a recurrence of C difficile after the initial infection, and one in nine patients over the age of 65 will die within 30 days of being diagnosed. While the infection is most common in older people or patients staying in a hospital or nursing home, it can occur at any age, even in childhood, according to Dr. Guo.
“We are facing a problem with recurring C difficile colitis in this country, so everyone is trying to find a treatment,” he said. “We typically use different antibiotics to treat a patient but a lot of people don’t respond very well to medication and it reoccurs in a lot of patients. When it continues to reoccur, it can be a really tough thing to get rid of. Patients are miserable when they have recurring C diff.”
So far the most effective treatment is fecal transplant. Doctors transplant fecal material from a healthy donor to the patient with C difficile. The methods used to do the transplant are enemas, colonoscopies or through a nasal gastric tube that is placed down the throat past the stomach to the small intestines.
“Other approaches do have a role to play, but we know that fecal transplant is very effective,” Dr. Guo said. “When the donor is a family member it shows between 95 and 100 percent efficacy.”
Family members are the best donors because they are very likely to have been exposed to C diff, but they didn’t get C diff. They have the bacteria that can suppress it, he said.
Studies that compare the different approaches show that upper GI tract given is much less effective than the material given through the colonoscopy, Dr. Guo added.
Because fecal transplants deal with biological material, donors have to be screened for blood and body illnesses like hepatitis and HIV. A big hurdle to treatment is that insurance companies do not cover the screenings, he said. One solution has been developed by the Somerville non-profit OpenBiome, which provides safe access to fecal microbiota preparations made from donations from rigorously screened donors.
Another Option on the Horizon
Another promising treatment was developed by MassBiologics at UMass Medical School and licensed to Merck in 2009. Bezlotoxumab is an antibody that can neutralize C difficile toxin B, the most dangerous of the C diff toxins. The results of two world-wide phase three trials were presented last September at the joint meeting of the Interscience Conference of Antimicrobial Agents and Chemotherapy and the International Congress of Chemotherapy and Infection.
In the trial, patients were given an infusion of bezlotoxumab alone, or paired with actoxumab (an anti-body for treating C difficile toxin A) or a placebo. According to Merck, the combination with toxin A was no more effective than the bezlotoxumab alone after 12 weeks, so they decided to focus on just toxin B for regulatory approval.
“It seemed quite effective, but in the trial it was not 100 percent effective,” Dr. Guo said explaining that the effectiveness against recurrence was about half compared to the placebo group.
Bezlotoxumab was presented to the Food And Drug Administration Meeting of the Antimicrobial Drugs Advisory Committee on June 9, 2016. The committee voted for approval 10 to five with one abstention. Even those who voted to approve it had some reservations. The committee said that it would have liked to have seen a larger population to determine which patients would benefit the most from the treatment.
The treatment was scheduled for a target action date of July 23, but the FDA extended that date by three months and requested new data and analyses from the trials. The new target date was delayed until October 23.