Efficacy of ChAd63 MVA ME-TRAP prime-boost vaccination

Malaria transmission is falling in some parts of Africa as bed nets and anti-malarials become more widely available. However, transmission still persists and it appears that additional control measures are required. The leading malaria vaccine candidate in development is RTS,S which has efficacy against clinical malaria measured at 30-50% in the field. This partial protection might be enhanced by combination with other components. The other vaccination approach that has produced repeatable efficacy in humans is the use of viral vectors to induce T-cell responses. Previous attempts with this vaccine approach have been effective in challenge studies in Oxford, but ineffective in the field, probably because of reduced immunogenicity.
Recently, studies in Oxford, Kenya, and the Gambia have shown higher levels of immunogenicity by using a chimpanzee adenovirus (ChAd63) followed by an attenuated vaccinia virus (modified vaccinia Ankara) to deliver the pre-erythrocytic antigen, multiple epitope string with thrombospondin- related adhesion protein (ME-TRAP).
The increase in immunogenicity has led to sterile protection in 3 out of 14 volunteers and partial protection in 5 out of 14 volunteers in challenge studies.

Study type: Interventional
Enrollment: 120 participants
Primary purpose: Prevention
Allocation: Randomized
Interventional Model: Parallel assignment
Masking : Single (Participant)
NCT number: NCT01666925
Phase: Phase II

Clinical trial registration

Vaccines

Mar 2012 — Aug 2012

Kenya