Treatment with Monoclonal Antibodies againstClostridium difficileToxins

Abstract

To the Editor: The findings by Lowy and col­ leagues (Jan. 21 issue)1 demonstrate the value of fully human monoclonal antibodies in prevent­ ing the recurrence of Clostridium difficile infection. The prevalence of C. difficile infection in hospital­ ized patients is greatest among patients older than 85 years of age,2 and recurrent C. difficile infection is both more frequent and more problematic in older adults.3 Although the oldest patient in the trial con­ ducted by Lowy et al. was 101 years old, the mean age was 64 years. We recently reported that the natural history of C. difficile infection in frail, elder­ ly patients is different from that in younger pa­ tients. In randomized trials of metronidazole and vancomycin, the “cure” rate among patients (mean age, approximately 60 years) was typically higher than 80% within the first week after treatment; in contrast, at least half the elderly patients with acquired C. difficile infection in our geriatrics department (mean age, 86 years) re­ mained symptomatic at 2 weeks.4 Consequently, we are not satisfied that it will be valid to ex­ trapolate the results from the study by Lowy et al. to the patients at greatest risk for C. difficile infec­ tion. Issues regarding the inclusion of elderly patients in clinical trials have been raised previ­ ously.5 Specific evaluation of antibiotic and bio­ logic agents for C. difficile infection in older adults is needed. Tom Parks, M.B., B.Chir.