HIV/AIDS Vaccine For Healthy Individuals Tested For Safety, Tolerability

Known as a Phase I clinical trial, the UC Davis study will test the safety and tolerability of genetically engineered vaccines that have been designed to protect the body against HIV infection. Developed by Merck Research Laboratories, the test vaccine includes three pieces of HIV known as Gag, Pol and Nef. This next-generation vaccine is based on the use of a non-infectious particle known as an adenovirus. Because this vaccine is produced through genetic engineering techniques, it does not contain any live HIV virus and cannot cause HIV infection.

The adenovirus serotype 5 HIV-1 vaccine contains a man-made copy of the HIV-1 gag-pol-nef genes but uses a defective, non-infectious respiratory virus (adenovirus) as a backbone. Like the previous test vaccines, it is designed to stimulate the immune system to develop an immune defense against the HIV proteins.

“The goal of this study is to evaluate the safety of this vaccine and to measure the immune system’s ability to respond to the vaccine.” said David Asmuth, assistant professor in the Division of Infectious Diseases at UC Davis School of Medicine and Medical Center and principal investigator of the study. “This vaccine is an expanded version of the previous candidate vaccines designed to elicit a broader, and hopefully, more effective response to HIV. The previous versions were generally well tolerated in volunteers tested and their effect on the immune system is still being tested. Merck Research Laboratories has made a commitment to developing an effective vaccine against HIV and we are grateful to be invited to participate in this important cause.”

The trial is a “double-blind” study, with some participants receiving the test vaccines and some participants receiving a placebo, an inactive substance used as a comparison. Neither the volunteers nor the research staff will know which product is being administered. Participants receive the test vaccine by muscle injection.

Initial safety and tolerability studies of this HIV-1 adenovirus vaccine were done in animals and several hundred healthy volunteers. These studies have shown the previous versions of the vaccine to be generally well-tolerated. The most common symptoms reported have been injection site pain and headache. Merck is currently conducting several studies in healthy volunteers using the adenovirus vaccine, which has been generally well tolerated to date. Information from this study is still being collected.

UC Davis researchers emphasize that this trial involves a test vaccine. They will not enroll anyone whose motive for participation is to use the vaccine as a reason to increase risky behaviors by counting on the vaccine to act as protection against HIV.

“Participating in this trial is one way to make an important contribution to HIV vaccine research,” said Asmuth. It will take a sustained and probably lengthy effort to develop a vaccine that stops HIV in United States and around the world. This trial is an important step in reaching that goal.”

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TO PARTICIPATE IN THE STUDY, volunteers must be healthy males or females between the ages of 18 and 50 who currently are HIV-negative and at low risk for acquiring HIV infection. Individuals who are pregnant or nursing, or who have hepatitis C or hepatitis B infection are not eligible for the study.

Study participants will visit UC Davis Medical Center 20 times over an 18-month period to receive a series of three vaccine injections and then will be seen briefly an additional 4 times over the following three and a half years (5 years total). Blood and urine samples will be taken and other tests conducted at regular intervals. All volunteers will receive extensive counseling that will focus on reducing the chance of becoming exposed to HIV.

For more information about enrolling in this study, contact Tammy Yotter, study coordinator, at (916) 734-0591.

Copies of all news releases from UC Davis Health System are available on the Web at http://www.ucdmc.ucdavis.edu/news/.