ViroPharma announces results of VP20621 Phase 2 study for preventing recurrent CDI

ViroPharma Incorporated (Nasdaq: VPHM), an international biopharmaceutical company committed to developing and commercializing innovative products that address unmet medical needs and rare diseases, today announced the results of a Phase 2 study of VP20621 (non-toxigenic Clostridium difficile; NTCD) a novel treatment approach for preventing recurrent C. difficile infections (CDI). CDI is a common and dangerous gastrointestinal infection typically occurring in older adults after use of antibiotic medications. VP20621 contains the spores of a naturally occurring non-toxin producing strain of C. difficile. 

In this study of 168 patients who were randomized and dosed following antibiotic treatment for CDI, VP20621 was well tolerated, with mild-moderate headache the only notable associated adverse event reported by 10 percent of subjects compared to 2 percent on placebo. Viable non-toxigenic C. difficile was detected in stool culture (the primary endpoint of the study) in 54 percent of subjects treated with the low dose of VP20621 and up to 79 percent of those receiving the high dose. In addition, across all dose groups, VP20621 reduced the incidence of CDI recurrence (a secondary endpoint of the study) by greater than or equal to 50 percent vs. placebo, with a similar reduction in antibacterial treatment for CDI vs. placebo in this study. The CDI recurrence rate was two percent (2/86) in the subgroup of patients successfully colonized with VP20621.

"These data demonstrate that colonization with VP20621 was achieved in the majority of patients, and that in these patients, 98 percent had no recurrence of C. difficile infection," commented Dr. Colin Broom , ViroPharma's chief scientific officer. "We have long known that colonization of susceptible individuals with a non-toxin-producing strain of C. difficile appears to prevent infection by a toxic, virulent strain and these data support that observation. The results of the study provide insight into how colonization rates may be increased further, for example, by starting VP20621 dosing earlier and using the optimum dosing regimen in confirmatory studies powered to show a difference in recurrence rates. These are very exciting data, and offer clinicians and patients hope that a preventive therapy for recurrent CDI may one day be available to them."