Clinical Trial of the BioMed rTSST-1 Variant Vaccine in Healthy Adults

The BioMed rTSST-1 Variant Vaccine has been developed by Biomedizinische ForschungsgmbH as one component of a polyvalent staphylococcal vaccine for the prevention of toxic shock and hyperimmunization of donors for the production of TSST-1 immunoglobulin.

This is a prospective, randomized, parallel control, phase 2 study of extended safety, local tolerance, immunogenicity, and TSST-1 antibody persistence in healthy adults, who have been vaccinated with one, two or three doses of the BioMed rTSST1 Variant Vaccine compared to adjuvant.

Over a period of 60 days prior to entry into the study, 145 male and female subjects 18 - 64 years in age will be screened for eligibility. Screening criteria will include physical examination, medical history, pregnancy/ adequate contraception in females, HIV Ab, hepatitis C virus antibodies (HCV Ab), hepatitis B antigen (HBs Ag) and TSST-1 Ab. 140 qualified subjects will be entered into the study.

Group 1 will receive 10 µg of rTSST-1 Variant Vaccine and two administrations of Adjuvant; Group 2 will receive the same dose of Vaccine twice and one dose of Adjuvant; and Group 3 will be injected the 10 µg of the Vaccine three times. Groups 4 to 6 will be given 100 µg of Vaccine following the same schedule. Group 7 will receive Al(OH3) adjuvant three times.

Prior to, and 24 h (+3 h) after each vaccination, the subjects will be examined for vital signs. Blood will be drawn for hematology, clinical chemistry tests, and C-reactive protein. Local reactions and adverse events will be assessed in all post vaccination visits.

The subjects will be followed up for a period of 3 months (± 2 weeks) or optionally 18 months (± 12 weeks) if they decide to take part in the long-term follow-up, during which they will return to the clinic every three months (± 2 weeks). Tests performed will include vital signs, local reactions, clinical chemistry, C-reactive protein. Adverse events will be recorded.

Binding and neutralizing TSST-1 antibodies will be determined prior to each vaccination and every three months during the treatment and follow-up periods.

Each participant will be in the study for 12 to 14, or optionally 24 months, if they decide to take part in the long-term follow-up.

Immunogenicity is defined by seroconversion from a TSST-1 Ab titer of < 20 to > 40 or a 4-fold increase in TSST-1 Ab titer. Neutralization will be defined as a three-fold increase of neutralization titer.

Inclusion criteria

• males or females aged 18-64 years
• signed informed consent
• physical exam: no abnormal findings unless considered irrelevant by the investigator
• uneventful medical history
• Females with childbearing potential: adequate contraception

Exclusion criteria

• females with childbearing potential: pregnancy, lactation or unreliable contraception
• positive HIV Ab and/or positive HCV Ab and/or positive HBsAG signs and symptoms of autoimmunity
• TSST-1 Ab titer > 1:1000
• current or recent (< 1 month) immunosuppressive therapy with corticosteroids or immunomodulators