Safety and Immune Response Study of High-Dose Canarypox ALVAC-HIV Vaccine in Healthy, HIV Uninfected Adults

To date, adverse reactions to immunization with the various ALVAC-HIV candidate vaccines, including ALVAC-HIV (vCP1452), have been similar to those observed in healthy adults who have received other licensed vaccines of similar types. In a previous trial, even high doses of recombinant ALVAC vaccine were well tolerated in a group of participants that were significantly immunocompromised. In a recent study done in mice concerning dose escalation using the ALVAC-HIV vectors, the data demonstrated more robust immune responses with higher doses of ALVAC-HIV (vCP1452) in mice. It is certainly possible that the doses of ALVAC-HIV given to humans are well below the amount needed for a maximal cytotoxic T lymphocyte (CTL) response. As the predictive value of a CTL response is at present unknown with respect to its efficacy in preventing or ameliorating HIV acquisition or infection, the HVTN will utilize the highest dose that can be currently manufactured. All study products are to be administered intramuscularly. Participants will receive 1 of 3 injections. Group A will receive a high dose of vaccine, group B will receive a low dose of vaccine, and group C will receive a placebo. Participants are inoculated at 4 time points. Assessment of product safety includes clinical observation, monitoring of hematological, chemical, and immunologic parameters, and a social harms questionnaire. Safety will be evaluated by monitoring of participants for local and systemic adverse reactions during the course of the trial. Participants will be monitored longitudinally for HIV-specific serologic and cellular immune responses.