A Phase I Study of the Safety and Immunogenicity of a Recombinant MVA Vaccine Encoding a Secreted Antigen From M. Tuberculosis, Antigen 85A, Delivered Intradermally by a Needle Injection in Healthy Volunteers Who Have Received BCG Immunisation 1 Month Previously

Overview

This is a phase I study to test the immunogenicity of a recombinant vaccine based on Modified Vaccinia Ankara (MVA) expressing the antigen 85A (from Mycobacterium tuberculosis). This vaccine is delivered intradermally by a needle injection in healthy volunteers previously vaccinated with BCG.

This is a phase I study to test the immunogenicity of a recombinant vaccine based on Modified Vaccinia Ankara (MVA) expressing the antigen 85A (from Mycobacterium tuberculosis). This vaccine is delivered intradermally by a needle injection in healthy volunteers who have recieved a BCG immunisation month previously. 1. Selection of volunteers Volunteers for the study will be recruited through advertisements. Each volunteer will have received an information sheet concerning the study and will have agreed to participate in writing. Volunteers will be given at least 48 hours between reading the information leaflet and agreeing to participate. Female volunteers will be told of the theoretical risk of congenital anomaly should they become pregnant during the study and only those who undertake to take precautions to avoid pregnancy during the study period will be eligible. Volunteers will give signed consent for their GP's to be notified about their participation in the trial. The GP will be faxed a letter on the day of screening and asked to reply if they know of a reason why the volunteer should not take part. The signed consent form will also be faxed with the letter. 2. Screening Volunteers will be asked to sign the informed consent form for screening. The following will be performed: * Medical history and examination * Laboratory evaluations - including clinical chemistry, haematology, HLA typing, anti-vaccinia antibodies, anti-HBV antibodies, anti-HCV antibodies, anti-HIV antibodies * Heaf test - to exclude prior exposure to TB * Urinalysis and urine pregnancy test if female 3. Inclusion Criteria * Healthy adult aged 18-55 years. * Normal medical history and physical examination. * Normal urine dipstick, blood count, liver enzymes, and creatinine. 4. Exclusion Criteria 1. Exposure to TB/BCG vaccination at any point. Previous residence in a TB endemic area. 2. Clinically significant history of skin disorder (eczema, psoriasis, etc.), allergy, immunodeficiency, cardiovascular disease, respiratory disease, endocrine disorder, liver disease, renal disease, gastrointestinal disease, neurological illness, psychiatric disorder, drug or alcohol abuse. 3. Oral or systemic steroid medication or the use of immunosuppressive agents. 4. Positive HIV antibody test, HCV antibody test or positive HBV serology except post-vaccination. 5. Heaf test greater than Grade 0 6. Confirmed pregnancy 7. Previous MVA immunisations 5. Withdrawal Criteria 1. Withdrawal of consent by subject for any reason 2. Loss to follow-up 3. Non-compliance with study procedures 4. Protocol violation 5. Serious adverse event (as defined in Appendix 3) 6. Any other reason at discretion of the Principal Investigator 7. Confirmed pregnancy during study period 6. Immunisation On Day 0, subjects will receive a single intradermal injection of 0.1ml BCG (SSI strain) over the deltoid muscle. Blood will be taken at 2 weeks and 4 weeks after this immunisation. At 4 weeks, after blood has been taken, volunteers will be immunised with 5 x 107pfu MVA85A in 0.1ml. Subjects will be observed for an hour after MVA85A immunisation. Vital signs will be monitored at 30 and 60 minutes post-immunisation. Local reactions at the site of administration will be evaluated at 60 minutes. A photograph of the injection site may be taken at 48 hours (with written consent). The injection site will be reviewed 7 days after each immunization. Blood will be taken at the following time points: At the screening visit\*, prior to the BCG vaccination, 2 weeks and 4 weeks after BCG, \*1 week after the MVA85A vaccination, 2 weeks, 4 weeks, \*8 weeks, and \*24 weeks after the vaccination. Up to 55 mls will be taken at any one time with the total being no more than 500 mls over the study period. \*Samples taken on these dates will be tested for full blood count and biochemical screen. Immunological assays will be performed at all time points to determine vaccine immunogenicity. A pregnancy test will be performed prior to vaccination for female volunteers. Peripheral blood mononuclear cells will be prepared for cellular immunological assays to be performed without or following cryopreservation. Other serological measures of immune response, i.e. antibody titres, will be assayed on frozen plasma samples. All blood tests will be taken within 1-3 days of the due date as described in the schedule above. 7. Endpoints The occurance and severity of local side-effects The occurance and severity of systemic side-effects The induction of T cell responses (as measured by an interferon-gamma Elispot assay). Proliferation assays and cytotoxic T cell assays will be performed on strong CD4+ and CD8+ responses respectively.