Clinical

CPG 7909 boosts hepatitis B virus vaccine seroprotection in HIV-infected adults

Last Updated: 2005-10-27 15:04:54 -0400 (Reuters Health)

By Will Boggs, MD

NEW YORK (Reuters Health) - The CPG 7909 adjuvant enhances the seroprotection afforded by hepatitis B virus vaccine in HIV-infected adults receiving antiretroviral therapy, according to a report in the September 23rd issue of AIDS.

"CPG-containing adjuvants possess great potential to increase the level and breadth of protection achieved with vaccination," Dr. Curtis L. Cooper from The Ottawa Hospital, Ontario, Canada, told Reuters Health.

Synthetic oligodeoxynucleotides containing CpG motifs potently stimulate the innate immune response, the authors explain, and such oligodeoxynucleotides have shown efficacy as vaccine adjuvants in preclinical studies in rhesus macaques.

Dr. Cooper and colleagues investigated the safety and efficacy of CPG 7909 as an adjuvant to Engerix-B hepatitis B virus vaccine in 19 HIV-infected adults. Nineteen HIV-infected adults received vaccine only.

Most subjects reported at least one adverse event during the course of the study, the results indicate, but most events were of mild-to-moderate intensity and included local injection site reactions and influenza-like symptoms.

Antibody to hepatitis B surface antigen was higher at all time points after the second injection for subjects receiving vaccine with CPG 7909 than for subjects receiving vaccine alone, the authors report.

All subjects seroconverted by week 10, the report indicates, and antibody persisted to 48 weeks in all recipients of vaccine plus CPG 7909 and in 17 of 19 recipients of vaccine only.

Similarly, the researchers note, seroprotective titers remained in all CPG 7909 recipients at 48 weeks versus 12 of 19 (63%) of vaccine only recipients.

Lymphocyte proliferative responses to ex vivo restimulation with hepatitis B surface antigen were also more robust in vaccine plus CPG 7909 recipients than in vaccine only recipients.

"CPG-containing oligodeoxynucleotides can be used effectively to modulate immune responses to vaccination and, potentially, against infection," Dr. Cooper said. "We have conducted one study with influenza vaccine and would like to pursue additional studies in high risk/poor responding populations. We would like to pursue additional HIV and HCV-related work with CPG adjuvants."

Dr. Cooper added that a phase III study of CPG 7909 is also planned.

AIDS 2005;19:1473-1479.