A Phase I Study to Assess the Safety and Immunogenicity of New TB Vaccine Candidates FP85A and MVA85A, in Healthy Adults Who Have Previously Been Immunized With BCG, Using a Prime-boost Delivery Schedule
A Phase I Study to Assess the Safety and Immunogenicity of New TB Vaccine Candidates FP85A and MVA85A, in Healthy Adults Who Have Previously Been Immunized With BCG, Using a Prime-boost Delivery Schedule
This is a Phase I study whose primary outcome is to assess the safety of a new tuberculosis vaccine, FP85A, when administered individually and sequentially with MVA85A in a prime-boost regime, to healthy volunteers, who have previously been vaccinated with BCG. The secondary outcome is to assess the cellular immune response in the same population. The trial consists of 36 subjects in 3 groups. The first group will be vaccinated with FP85A alone, the second group will be vaccinated with MVA85A followed by FP85A 28 days later and the third group will be vaccinated with FP85A followed by MVA85A 28 days later.
Recombinant fowlpox virus as a vector
Fowlpox virus is only infectious to avian species, but it is able to express antigens in mammalian cells and induce protective immune responses, making it a suitable candidate vector. Recombinant fowlpox viruses have been developed that express antigens from tumour cells, HIV and malaria. FP9 is a live, highly attenuated form of a European strain of fowlpox virus. It was derived from multiple passages in avian cells, followed by plaque purification and the genome has been fully characterised. Fowlpox virus was initially used as a recombinant avian vaccine, but it has also been shown to be a potent inducer of CD8+T cells in preclinical mammalian models and in human trials . In fact, FP9 was found to be more immunogenic than wild type fowlpox and, when used with recombinant MVA in a prime boost regime induced a protective immune response against Plasmodium berghi.
Clinical experience with recombinant fowlpox viruses in Oxford Three FP vaccines encoding different malaria antigens have been used so far in clinical trials in Oxford, FP9 ME-TRAP, FP9 CS and FP9 PP. To date 87 doses of FP9 ME-TRAP have been given to 55 volunteers in Oxford using various regimens in combination with DNA as well as recombinant MVA vaccines. The local and systemic safety profile of FP9 ME-TRAP is comparable to that described for recombinant MVA vaccines. No vaccine-related serious adverse events have been observed. Pain and erythema at the injection site are the predominant local side effects, with the erythema being maximal within 2 to 3 days post-vaccination before receding. The commonest systemic side effect after FP9 ME-TRAP is of feeling feverish although this is not always associated with a documented fever. Other solicited side effects are myalgia, arthralgia, headache and nausea. FP9 CS has been used recently in a phase I study in 25 healthy volunteers in Oxford, at doses of 1x10^8 pfu. Analysis of safety and tolerability suggests similar side effect profile to FP9 ME-TRAP. No serious adverse events were noted in the study. In a phase I/IIa study which is nearing completion, 15 volunteers were immunised with 5x10^7 pfu of FP9 PP, with no vaccine-related serious adverse events and comparable adverse events.
Inclusion Criteria:
Exclusion Criteria: