An early trial of Inovio Pharmaceuticals’ experimental HIV vaccine showed considerable success in prompting immune-cell and antibody responses to the virus. Nearly all those who received the four-dose vaccine, which was paired with an immune activator, developed a CD4 immune-cell response, and a majority developed a CD8 immune-cell response to HIV; almost all produced HIV-specific antibodies.
The randomized, placebo-controlled multicenter Phase I HVTN 098 trial included 94 HIV-negative participants, 85 of whom were randomized to receive the vaccine, known as PENNVAX-GP, and nine of whom were randomized to receive a placebo. The trial is supported by the HIV Vaccine Trials Network (HVTN) and the National Institute of Allergy and Infectious Diseases (NIAID).
Findings were presented at the 2017 HVTN Spring Full Group Meeting in Washington, DC.
PENNVAX-GP includes four HIV antigens, or viral proteins, that apply to multiple strains of the virus seen worldwide. The vaccine has been constructed to prompt both antibody and immune-cell responses, with the goal of using it to prevent and even treat HIV. Given in four doses, the vaccine is combined with a DNA-encoded immune activator known as IL-12.
Participants received the vaccine either through injections into the skin (intradermal) or the muscle (intramuscular). The intramuscular dose was one fifth that of the intradermal.
Ninety-three percent (71 of 76) of the participants for whom there was evaluable data developed a CD4 or CD8 immune-cell response to at least one of the four vaccine antigens, including those known as env A, env C, gag and pol. Ninety-four percent (62 of 66) of evaluated participants produced antibodies specific to HIV’s outer casing, or envelope. None of the nine participants who received the placebo developed an immune-cell or antibody response to the vaccine.
Ninety-six percent (27 of 28) of those evaluated who received the vaccine intradermally developed an immune-cell response and 96 percent (27 of 28) developed an HIV-envelop-specific antibody response. One hundred percent (27 of 27) of those evaluated who received the vaccine intramuscularly demonstrated an immune-cell response, and 90 percent (19 of 21) developed an antibody response.
To read a press release about the study, click here.