Company on track to initiate clinical trials late this year or early 2002 of epitope-based vaccine for the prevention and treatment of HIV

Keystone, CO, April 2, 2001 - Epimmune Inc. (Nasdaq: EPMN) today announced positive pre-clinical data on its HIV vaccine that is designed to directly address the problem of viral mutation. At the Keystone Symposium: "AIDS Vaccines in the New Millennium" on March 30, 2001 in Keystone, Colorado, Company scientists reported that the vaccine stimulated multiple anti-HIV cytotoxic T-cell immune responses in animal models. Epimmune has begun manufacturing the vaccine for human testing and plans to initiate clinical trials late this year or early 2002 in both non-infected volunteers and in individuals infected with HIV.

The current standard HIV therapy for Americans is a three-drug anti-retroviral combination that costs approximately $15,000 per year. While anti-retroviral drugs are effective at suppressing HIV replication in infected individuals, they do not eliminate the infection and have toxic side effects that impede their long-term use. A vaccine that can provide both preventative and therapeutic benefits has great potential to help control the AIDS epidemic and curtail the costs and side effects of anti-retroviral therapies.

"A major challenge to the development of an effective AIDS vaccine is the ability of HIV to mutate. Epimmunes vaccine is designed to directly address this problem," said Mark Newman, Ph.D., Vice President of the Infectious Disease Program at Epimmune. "One of the unique features of Epimmunes vaccine is that it is composed of epitopes, or protein fragments, which are strategically selected from non-mutating regions of HIV. As a result, it is expected to be harder for the virus to develop variants that can escape the vaccine-induced immune response."

Strong cellular immunity is characteristic of long-term non-progressors or HIV-positive individuals
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Contact: Laura Hansen
lhansen@irpr.com
858-860-0266
Epimmune, Inc.
1-Apr-2001