The purpose of this study is to determine the safety and tolerability of a modified C. difficile vaccine at 3 dose levels compared with a placebo control administered via intramuscular injection in healthy adults aged 18-55 years of age.
Clostridium difficile is the leading infectious cause of nosocomial diarrhea in developed countries. Hospital outbreaks of Clostridium difficile-associated diarrhea (CDAD) are associated with substantial patient morbidity and mortality. Conventional therapy with antibiotics often results in secondary infection with resistant organisms or clinical relapse after discontinuation of the antimicrobial course. New strategies are needed to limit the impact of this opportunistic pathogen. Considerable evidence exists that immunity against C. difficile toxins may be effective in controlling CDAD. 48 subjects will be enrolled to receive one of three dose levels of modified C difficile vaccine or placebo administered on a 3-dose schedule. The study consists of a 30-day screening period, a 70-day treatment period, one follow-up phone interview 2 months after the last vaccination, and one follow-up clinic visit 6 months after the last vaccination.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
50
0.5 mL, intramuscular (IM) on Days 0, 28, and 56, respectively.
0.5 mL, intramuscular on Days 0, 28, and 56, respectively.
0.5 mL, intramuscular on Days 0, 28, and 56, respectively.
Number of Participants Reporting Solicited Injection Site Erythema and Tenderness Post-vaccination With Either One of Three Formulations of Clostridium Difficile Vaccines or a Placebo Vaccine.
Time frame: Day 0 and up to 7 days post each vaccination
Number of Participants Reporting Treatment-Emergent Adverse Events Post-vaccination With Either One of Three Formulations of the Clostridium Difficile Vaccine or a Placebo Vaccine.
Time frame: Day 0 to up to 70 days post-first vaccination
Number of Participants With Seroconversion for Toxin A and Toxin B Post-vaccination With Either One of Three Formulations of the Clostridium Difficile Vaccine or a Placebo Vaccine.
Seroconversion was defined as a ≥4-fold increase in antibody levels from Baseline. For values below the limit of quantification (LLQ) for the assay, the LLQ was used. Serum anti-toxin IgG levels were determined by enzyme linked immunosorbent assay (ELISA).
Time frame: Days 28, 56, 70, and 236 Post First Vaccination
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0.5 mL, intramuscular on Days 0, 28, and 56, respectively.