pTHr.HIVA is is an experimental therapeutic vaccine currently being tested in people with HIV. Therapeutic vaccines are being developed for use in HIV-infected people to stimulate the immune system and slow the progression of HIV disease.

pTHr.HIVA is a prime-boost DNA gag / multi-epitope vaccine. That is, it contains a portion of DNA which encodes some HIV genes (e.g. gag), and a synthetic segment of virus. Experts hope the this type of experimental vaccine, which combines two types of vaccine technology, will be able to improve HIV-specific immune responses in infected people.

pTHr.HIVA is being developed by the Oxford-based team led by Andrew McMichael which is also testing an experimental preventative vaccine.

The vaccine has been administered to six HIV-infected people who had undetectable viral load while on highly active antiretroviral therapy (HAART). No side-effects have been reported, and all maintained undetectable viral load. Some HIV-specific immune responses have been observed in immunised patients, although the results are preliminary (Dorrell 2003).

Reference

Dorrell L et al. Safety and immunogenicity of a candidate HIV-1 DNA gag/multi-epitope vaccine, pTHr.HIVA, in HIV-1 seropositive subjects receiving HAART. Tenth Conference on Retroviruses and Opportunistic Infections, Boston, abstract P645, 2003.