Clostridium Difficile Vaccine Efficacy Trial
Condition: Clostridium Difficile Infection
MeSH terms: Clostridium Infections
Intervention: Clostridium difficile vaccine; Placebo
Intervention description: Toxoid-based Clostridium difficile vaccine; Normal saline solution (0.9% sodium chloride)
Phase: Phase 3
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 17535.0
Sex: All
Minimum age: 50 Years
Healthy volunteers: Accepts Healthy Volunteers

Summary:

      The Clover trial is evaluating an investigational vaccine that may help to prevent
      Clostridium difficile infection. Participants in the study are adults 50 years of age and
      older, who are at risk of developing Clostridium difficile infection. The study will assess
      whether the vaccine prevents the disease, and whether it is safe and well tolerated.

      Each subject will receive 3 doses of Clostridium difficile vaccine or placebo and be followed
      for up to 3 years after vaccination for potential Clostridium difficile infection.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Evidence of a personally signed and dated informed consent document.

          -  Willing and able to comply with study procedures.

          -  Subjects with an increased risk of future contact with healthcare systems or subjects
             who have received systemic antibiotics in the previous 12 weeks.

          -  Ability to be contacted by telephone during study participation.

          -  Negative urine pregnancy test for female subjects of childbearing potential.

        Exclusion Criteria:

          -  Investigator site staff members directly involved in the conduct of the study and
             their family members, site staff members otherwise supervised by the investigator, or
             subjects who are Pfizer employees, including their family members, directly involved
             in the conduct of the study.

          -  Participation in other studies involving investigational drug(s)/vaccine(s) within 28
             days prior to study entry until 1 month after the third vaccination.

          -  Previous administration of an investigational C difficile vaccine or C difficile mAb
             therapy.

          -  Prior episode of CDI..

          -  Receipt of blood products or immunoglobulins within 6 months before enrollment.

          -  Subjects who may be unable to respond to vaccination due to:

               -  Metastatic malignancy; or

               -  End-stage renal disease; or

               -  Any serious medical disorder likely to be fatal within the next 12 months; or

               -  Congenital or acquired immunodeficiency; or

               -  Receipt of high dose systemic corticosteroids for 14 days within 28 days of
                  enrollment; or

               -  Receipt of chronic systemic treatment with other known immunosuppressant
                  medications, or radiotherapy, within 6 months of enrollment.

          -  Known infection with human immunodeficiency virus (HIV).

          -  Any bleeding disorder or anticoagulant therapy that would contraindicate intramuscular
             injection.

          -  Any contraindication to vaccination or vaccine components, including previous
             anaphylactic reaction to any vaccine or vaccine-related components.

          -  Prior small- or large-bowel resection.

          -  Any condition or treatment resulting in frequent diarrhea.

          -  Other acute or chronic condition or abnormality that may increase the risk associated
             with study participation or IP administration or may interfere with interpretation of
             study results

          -  Pregnant or breastfeeding female subjects; male subjects and female subjects who are
             sexually active and at risk for pregnancy and will not/cannot use 2 methods of
             contraception