Jan. 20, 2010 -- New monoclonal antibodies can break the cycle of recurrent infections in patients plagued by C. diff, a clinical trial suggests.
C. diff -- Clostridium difficile -- is the most common cause of antibiotic-associated diarrhea and colitis. A particularly nasty strain of the bug, dubbed toxinotype III BI/NAP1/027, is linked to several large outbreaks.
It's a nasty bug, but what makes it worse is that about 25% of patients suffer recurrent bouts of infection. Some of these patients get into a spiral of multiple relapses despite treatment with powerful antibiotics.
Animal studies suggest that C. diff is vulnerable to lab-grown antibodies that attack the bacterium's A and B toxins. Now researchers at the University of Massachusetts MassBiologics research facility report that it greatly lowered C. diff recurrence in a medium-size clinical trial.
"The combined administration of [the] human monoclonal antibodies significantly reduced the recurrence of C. difficile infection," report Israel Lowy, MD, PhD, of Medarex Inc., and colleagues. Medarex is a wholly owned subsidiary of Bristol-Myers Squibb. Merdarex and MassBiologics have licensed the antibodies to Merck.
The antibodies are given in a single, two-hour infusion. The study, conducted at 30 sites in the U.S. and Canada, enrolled 200 patients receiving antibiotic treatment for lab-confirmed C. diffdiarrhea. Half the patients received the monoclonal antibodies, and half got an inactive placebo.
C. diff recurred in 25% of patients receiving placebo, but in only 7% of those receiving the antibodies: a 72% reduction in C. diff recurrence.
The treatment worked even better -- reducing C. diff recurrence by 82% -- in patients who already had suffered multiple relapses.
The treatment did not make the patients' initial C. diff disease any better or worse and did not shorten their hospitalization.
"The trial results are impressive," Lorraine Kyne, MD, MPH, of University College, Dublin, writes in an editorial accompanying the Lowy report. "This novel non-antibiotic approach is likely to offer hope to physicians and patients battling C. difficile infection."
The Kyne editorial, and the Lowy report, appear in the Jan. 21 issue of the New England Journal of Medicine.