ViroPharma presents Phase 1 study data of VP20621 at ICAAC 2010

Sep 16 2010

ViroPharma Incorporated (Nasdaq: VPHM) today announced the presentation of data from its Phase 1 study of VP20621 (non-toxigenic Clostridium difficile), a novel treatment approach for preventing recurrent Clostridium difficile infections (CDI), 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.  

The poster entitled 'Phase 1 Evaluation of an Oral Suspension of VP 20621, Spores of a Non-Toxigenic C. difficile Strain (NTCD), in Healthy Older Subjects Pretreated With Oral Vancomycin' is being presented today at the 50th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in poster session F1-2127b by Stephen Villano, M.D., ViroPharma's vice president of clinical research and development.

The Phase 1 study was designed to determine the safety and tolerability of VP20621 dosed orally as single and repeat escalating doses in healthy young (18 to 45 years of age) and older (60 years of age and older) adults.  Because VP20621 was shown to be well tolerated following single and repeat doses in younger and older healthy subjects, the company also performed repeat dosing in older adults following exposure to oral antibiotic.  The new data presented today was from healthy subjects above 60 years of age who were pre-dosed with oral vancomycin to disrupt their gastrointestinal flora and render them potentially susceptible to C. difficile colonization. Subjects were subsequently given either placebo or VP20621 doses of 10(4),10(6), or 10(8) spores (once daily for 14 days).  Conclusions from the study include:

• Multiple doses of VP20621 were generally well tolerated at all dose levels; there were no serious or severe adverse events, and no discontinuations from study drug due to adverse events.
• All 27 volunteers (100 percent) who were given VP20621 had positive non-toxigenic C. difficile stool cultures by day 6, suggesting that VP20621 rapidly colonizes the susceptible GI tract.
• No patient dosed with VP20621 tested positive for toxin-producing strains of C. difficile during the 28-day study period.
• By comparison, 5 of 9 subjects (56 percent) who received placebo (i.e. did not receive VP20621) tested positive for either toxin-negative or toxin-positive C. difficile during the study period.

"I am highly encouraged by the data from this Phase 1 study of VP20621, which for the first time support the tolerability and colonization effectiveness of non-toxigenic C. difficile, mimicking what we have inferred from observing colonization of patients with these organisms," commented Dale Gerding, M.D., Associate Chief of Staff for Research at the Hines VA Hospital.  "Colonization protection of VP20621 awaits demonstration in a Phase 2 clinical trial in CDI patients to confirm pre-clinical data and observational studies of natural colonization in humans that have demonstrated high levels of protection against CDI that approach 100%."

"Previous animal and clinical observational studies have described the prevention of symptomatic CDI by colonization of the large bowel with non-toxin producing strains of C. difficile," commented Dr. Colin Broom, ViroPharma's chief scientific officer.  "We now know that VP20621 appears to behave similarly, rapidly colonizing the large bowel and potentially protecting it from colonization with dangerous toxin-producing strains of C. difficile. We are excited by these positive data and expect to move rapidly into Phase 2 studies with VP20621 in the coming months. Our goal with VP20621 is to provide a novel, non antibiotic therapy to protect patients from colonization by virulent toxin producing bacteria until their normal, protective GI flora returns, thereby significantly reducing the incidence of recurrent disease for patients with CDI."