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IAVI-sponsored AIDS vaccine candidate for human trials approved in South Africa

Johannesburg, South Africa August 25, 2003 South Africa’s Medicines Control Council (MCC) has given approval for the start of a Phase I human trial of a preventive AIDS vaccine candidate under study by an international research team sponsored by the nonprofit International AIDS Vaccine Initiative (IAVI).

The vaccine candidate, named HIVA.MVA, was designed by the University of Nairobi in Kenya and University of Oxford in the UK. Phase I human trials of the vaccine candidate already have been completed in Kenya and the UK and are underway in Uganda.

Scientists agree that a preventive vaccine is the best hope to end the spread of the HIV/AIDS epidemic. A preventive vaccine would be given to people who are uninfected with HIV, to stimulate their immune systems to prevent them from becoming infected or going on to develop AIDS.

HIVA.MVA is the second preventive AIDS vaccine candidate that the MCC has cleared for human trials in South Africa. In June, the MCC gave approval for a Phase I trial of AVX101, designed by the US biotechnology firm AlphaVax Inc. The trial will be conducted by the HIV Vaccine Trials Network of the US government’s National Institute of Allergy and Infectious Diseases. A Phase I trial of AVX101 already is underway in the US.

With two different preventive AIDS vaccine candidates approved to be tested, South Africa which has one of the highest HIV infection rates in the world is now a key center in the global effort to discover a vaccine.

IAVI’s HIVA.MVA and AlphaVax’s AVX101 employ different vaccine design strategies. HIVA.MVA uses a vaccine strategy called modified vaccinia Ankara, a variant of the basis for the smallpox vaccine. AVX101 uses a vaccine strategy called Venezuelan Equine Encephalitis alphavirus vector.

“By studying different vaccine design strategies at once, rather than one at a time, South Africa will help reduce the time needed to identify which is the most effective,” says Dr Seth Berkley, MD, president and CEO of IAVI. “In the search for an AIDS vaccine, speed is of the essence. A preventive vaccine is our best hope to end the spread of an epidemic that infects 15,000 men, women and children around the world every day."

“What is happening in South Africa should be a model for the world," says Dr Tim Tucker, executive director of the South African AIDS Vaccine Initiative (SAAVI). "Local scientists are working in collaboration with international partners to streamline the process of discovering a preventive AIDS vaccine.” SAAVI coordinates AIDS vaccine research in South Africa.

The trials of IAVI’s HIVA.MVA and AlphaVax’s AVX101 are separate, but they will be conducted at the same sites: one in Soweto and the other in Durban.

Both the HIVA.MVA and AVX101 trials are expected to begin later this year. They are Phase I trials and seek to initially enroll roughly 50 volunteers each. Their aim is to test safety and gather preliminary data on the ability of the vaccine candidates to stimulate the immune system. If either candidate performs well in Phase I, it can advance to later stages of trials, including a large-scale trial that would involve thousands of volunteers over multiple years.

By conducting the HIVA.MVA and AVX101 trials side by side, South Africa will help gather data to address how an AIDS vaccine may be able to combat the varying subtypes of HIV that are circulating. IAVI’s HIVA.MVA is based on subtype A, which is common in east Africa. AlphaVax’s AVX101 is based on subtype C, the subtype most common in South Africa.

“Ideally, a single AIDS vaccine will be highly effective against all subtypes of HIV,” says Dr Wayne Koff, IAVI’s senior vice president for research and development. “Preliminary indications are that both of the vaccine candidates currently approved for testing in South Africa hold promise for meeting this goal, but only human trials will tell us for sure.”