Dose-Confirmation, Immunogenicity and Safety Study of the Clostridium Difficile Vaccine Candidate VLA84 in Healthy Adults Aged 50 Years and Older. Phase II Study

Inclusion Criteria

• Subjects aged ≥50 years of good general health, including subjects with pharmacologically controlled conditions like hypercholesterolemia, hypertension, or type 2 diabetes mellitus.
• Informed consent form has been signed and dated

Exclusion Criteria

• Subjects with any confirmed or suspected prior Clostridium difficile infection episode
• Previous vaccination against Clostridium difficile with any (investigational) vaccine or receipt of (investigational) monoclonal antibodies against Clostridium difficile toxins
• Use of any other investigational or non-registered medicinal product within 30 days prior to VLA84 vaccination at Visit 1 (Day 0) and throughout the entire study period.
• Active or passive vaccination four weeks before first vaccination at Visit 1 and during the entire study period, except for influenza (seasonal or pandemic) and pneumococcal vaccines which may be administered outside a 7-days interval before and after any trial vaccination
• Subject is pregnant, or lactating, or of childbearing potential (to be considered of non-childbearing potential, a female must be post-menopausal for at least 1 year or surgically sterile)
• Known thrombocytopenia, bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion or until Visit 4 (Day28), contraindicating i.m. vaccination as judged by the investigator
• Clinically relevant renal, hepatic, cardiac, pulmonary or central nervous disorders, as judged by the investigator. Subjects with hypercholesterolemia, hypertension, or type 2 diabetes mellitus requiring medication are allowed if disease is adequately controlled
• Receipt of blood or blood-derived products in the past 3 months or anticipation of such products during the study period
• Known congenital, hereditary or acquired immunodeficiency, including known infection with human immunodeficiency virus (HIV), administration of chronic (defined as longer than 14 days) immunosuppressants or other immune-modifying drugs within 30 days prior to VLA84 vaccination at Visit 1 (Day 0) and during the study until Visit 5 (Day 35). For corticosteroids this means prednisone or equivalent ≥ 0.05 mg/kg/day; topical and inhaled steroids are allowed. Periodic steroid injections, e.g., intra-articular, are not allowed within 30 days prior to first VLA84 vaccination at Visit 1 (Day 0) and until Visit 5 (Day 35)
• History of autoimmune disease, including Type I Diabetes mellitus. Subjects with vitiligo or thyroid disease taking thyroid hormone replacement are not excluded
• Any malignancy in the past 5 years. If treatment for cancer was successfully completed more than 5 years ago and the malignancy is considered to be cured, the subject may be enrolled
• Known hypersensitivity or allergic reactions to one of the components of the vaccine
• Inability or unwillingness to provide informed consent
• Persons who are committed to an institution (by virtue of an order issued either by the judicial or the administrative authorities)
• Persons who are in a dependent relationship with the sponsor, an investigator or other study team members, or the study center. Dependent relationships include close relatives and household members (i.e., children, partner/spouse, siblings, parents) as well as employees of the investigator or study center personnel