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Human Clinical Trial of a New DNA-MVA Vaccine Candidate Begins in Africa
A Phase I clinical trial beginning this month in Kericho, Kenya and later in Tanzania and Uganda, will evaluate a new vaccine combination. Together, these two vaccines aim to protect against diverse subtypes of HIV-1 prevalent in Africa, as well as North America, Europe, Asia and South America.
This small-scale trial, called RV262, will enroll 80 volunteers in East Africa, and will take about 18 months to complete. This study is designed to confirm the vaccine regimen’s safety, and to determine the types of immune responses it stimulates. Eleven HIV-uninfected volunteers in the U.S. have already received the full vaccine regimen to ensure its safety before the trial expanded into East Africa.
This unique prime-boost preventive HIV vaccination strategy is designed for global protection from various strains of HIV. The prime is a plasmid DNA vaccine, PENNVAX™-G, and the boost is a virus vector vaccine, Modified Vaccinia Ankara-Chiang Mai Double Recombinant (MVA-CMDR). Together, the vaccines are designed to deliver a diverse mixture of antigens for HIV subtypes A, B, C, D and E. The MVA component was developed using HIV isolates collected from these East Africa research sites.
Taken separately, DNA based and MVA based vaccine strategies have been shown to be safe and immunogenic in pre-clinical and clinical trials. Researchers hope they can enhance immune responses by using this prime-boost strategy. “The individual vaccine platforms contain inserts specifically designed for HIV protection, targeting different viral subtypes reflecting local circulating strains, and is referred to as a ‘heterologous prime-boost strategy’. The goal is to provide key genetic information to the immune system within different immunologic contexts so as to optimize the response,” noted Dr. Mary Marovich, the study's Principal Investigator.
Another unique factor in this trial is the way one of the vaccines is delivered. DNA vaccines have many advantages, but researchers are still trying to determine the best way to inject it into the body so that it can have maximum potency. To address this, researchers will test two intramuscular delivery methods for the DNA prime (PENNVAX™-G) to compare their effects on immune response. The two devices that will be tested in this study are the Biojector® 2000 and the CELLECTRA® EP (electroporation) device.
The Biojector is a needle-free injection system that has been widely used for delivering vaccines and other injected medications. The CELLECTRA EP system is a new intramuscular electroporation device currently being evaluated in clinical trials as an alternative vaccine delivery system to increase immune responses above those elicited by standard needle and syringe injections. Electroporation involves the application of controlled, millisecond electrical pulses to cells to enhance their uptake of the vaccine.
About the Vaccines
The DNA vaccine was designed in Prof. David B. Weiner’s laboratory at the University of Pennsylvania and licensed by Inovio Pharmaceuticals for further clinical product development. The boost vaccine component, based on Modified Vaccinia Ankara (MVA), is a modified version of the smallpox vaccine that has been used safely and effectively to eradicate that disease worldwide. The MVA vaccine component used in the study was developed by U.S. Military HIV Research Program (MHRP) scientists in collaboration with the NIAID Laboratory of Viral Diseases.
The National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health (NIH), is sponsoring the study, which is led by the U.S. Military HIV Research Program (MHRP). This clinical trial is a collaboration that includes Bioject Medical Technologies Inc., Inovio Pharmaceuticals, Inc., Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., NIAID and the U.S. Army/MHRP.