Tell me more about the CDiffense Study

The Cdiffense trial is sponsored by Sanofi Pasteur. The objective of the Cdiffense trial is to evaluate the safety, immunogenicity and efficacy of a toxoid vaccine for the prevention of primary symptomatic Clostridium difficile Infection ( CDI).

  • Participant recruitment will begin in August 2013 in the U.S. and will expand to 17 countries around the world.
  • The trial is planned to last for up to 3 years.
  • This is a placebo controlled trial, which means participants may receive either vaccine or placebo.
  • Participation in a clinical study is completely voluntary.
  • Throughout the study participants will be contacted regularly by telephone.
  • Candidates must qualify by meeting criteria in one of two categories:
  • Group 1:

    Have you had at least 2 hospital stays, each lasting at least ≥ 24 hours, in the past 12 months?


    Have you received systemic (not topical) antibiotics in the past 12 months?

    Group 2:

    Are you anticipating an in-patient hospitalization for a planned surgical procedure within the next 60 days?

    Is the upcoming hospital stay planned to be ≥ 72 hours for a surgery involving 1 of the following?

    • Kidney/bladder/urinary system
    • Musculoskeletal system
    • Respiratory system
    • Circulatory system
    • Central nervous system

About the Vaccine

  • The investigational C.diff vaccine is a toxoid vaccine which targets the toxins generated by the C.diff bacteria.
  • The vaccine stimulates a person’s immune system to fight C.diff toxins upon exposure and may prevent a future CDI from occurring
  • The U.S. Food and Drug Administration (FDA) granted fast-track designation to Sanofi Pasteur’s investigational C.diff vaccine candidate in 2010. The FDA’s fast-track program is designed to facilitate the development and expedite the review of new drugs and vaccines that demonstrate the potential to address unmet medical needs.

What is a Clinical Trial?

  • Clinical trials can vary in size from a single location in one country to multiple locations in multiple countries.
  • Some research studies may determine if an investigational product can be administered to children or special populations.
  • Some studies assess a drug’s long-term effectiveness and its impact on the quality of a person’s life.
  • All studies of a drug, biological product, or medical device regulated by FDA must be reviewed, approved, and monitored by an institutional review board (IRB) or Ethics Committee (EC).
  • All clinical trials are conducted using Principles of Good Clinical Practice (GCP) and are under the supervision of an IRB or EC whose mission is to ensure the safety and welfare of study participants.

The following websites have additional information on clinical trials: