Disappointing results from DNA/MVA AIDS vaccine candidates
At the Lausanne meeting, Walter Jaoko of the Kenya AIDS Vaccine Initiative (KAVI) reported disappointing early results from clinical trials testing two AIDS vaccine candidates: DNA.HIVA and MVA.HIVA. The trial was conducted in a partnership between IAVI, the University of Oxford, UK Medical Research Council, the University of Nairobi, KAVI and the Uganda Virus Research Institute. Both vaccines contain an HIV subtype A DNA carrying parts of the HIV genetic material. The DNA vaccine delivers the HIV DNA via a plasmid, a small circle of genetic material from bacteria. The MVA vaccine uses modified vaccinia Ankara as a vector (see Primer). The data presented was from 205 volunteers taking part in trials in Kenya, Uganda, and the UK. The vaccine candidates raised immune responses in only about a quarter of the people vaccinated and these responses were not long-lasting.
“The data fell short of our expectations,” said Emilio Emini of IAVI. Small clinical trials that have already been started to test DNA.HIVA and MVA.HIVA will continue for the next six to nine months in order to learn as much as possible about the candidates. “Unless the data significantly change, we’re not going to be developing those candidates further,” said Emini.