Treatment with the spores of nontoxigenic Clostridium difficile is well tolerated, and successful colonization of the gastrointestinal tract is associated with a significant reduction in C. difficile infection, according to a phase 2 study published May 5 in JAMA.
The randomized, double-blind, placebo-controlled study involving 173 patients with C. difficile infection showed that the lowest rate of recurrence (5%) was among the 43 patients who received the higher dose of 107 spores/day for 7 days, compared with 15% recurrence in those who received 107 spores/day for 14 days or 104 spores/day for 7 days, and 30% in the placebo group, reported Dr. Dale N. Gerding of Edward Hines, Jr. VA Hospital, Hines, Ill. and his associates.
The multicenter study, which involved patients who had all successfully completed treatment with metronidazole, oral vancomycin, or both, showed that fecal colonization occurred in 71% of patients who received the higher spore dose for 7 days and 63% of those who received the lower dose (JAMA 2015;313:1719-27 [doi:10.1001/jama.2015.3725]).
“The most likely hypothesized mechanism of action of NTCD-M3 [nontoxigenic C. difficile strain M3] is that it occupies the same metabolic or adherence niche in the gastrointestinal tract as does toxigenic C. difficile and, once established, is able to outcompete resident or newly ingested toxigenic strains,” Dr. Gerding and his associates wrote.
The study was sponsored by ViroPharma Incorporated. One author declared patents for the prevention of C. difficile infection, licensed to ViroPharma/Shire, and two authors were employees of ViroPharma/Shire during the study. Other authors reported personal fees, board positions, clinical trial participation, and consultancies with pharmaceutical companies, including the study sponsor.