CombiMatrix's siRNA Compounds Targeted Against HIV Will Be Tested by Leading European Researchers.

Business Editors/Health/Medical Writers

BIOWIRE2K

NEWPORT BEACH, Calif.--(BUSINESS WIRE)--June 30, 2003

Acacia Research Corporation (Nasdaq:CBMX) (Nasdaq:ACTG) announced today that CombiMatrix is collaborating with the research group of Dr. Bonaventura Clotet, M.D., Ph.D., of the Retrovirology Laboratory irsiCaixa, a leading research and treatment center for AIDS in Europe, to conduct the initial efficacy screening of pooled siRNA compounds against Human Immunodeficiency Virus, Type-1.

Dr. Amit Kumar, President and CEO of CombiMatrix said, "We are excited about working with Dr. Clotet and his laboratory. He is one of the world's leading HIV and siRNA researchers. Our systems biology approach, targeting all of the genes in a virus, may provide a more powerful therapy than conventional approaches, and it should make it difficult for the virus to develop resistance. The concept of drug cocktails for the treatment of HIV disease is the current standard of care. Most HIV patients take a pool or cocktail of anti-retroviral drugs to manage their disease. We hope our work with Dr. Clotet will help validate our approach against HIV, and get our compounds into a development program quickly."

"Gene silencing by siRNA continues to be a focus of our HIV research program at Retrovirology Laboratory irsiCaixa," said Dr. Clotet. "We are in the process of validating CombiMatrix's HIV gene targeted siRNA pools and are excited about our collaboration with CombiMatrix. The CombiMatrix approach to generating siRNAs allows for quick production of pools of siRNA and potentially the development and delivery of combinations of multiple HIV targeted siRNA to induce highly active anti-retroviral gene silencing or HAAGS."

The HIV project is CombiMatrix's second collaboration based on its Express Track(sm) siRNA drug discovery platform, following an earlier collaboration based on SARS with the National Institute of Allergy and Infectious Diseases (NIAID) and the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID). CombiMatrix is also in discussions regarding additional collaborations in other viral disease areas.

CombiMatrix's customizable microarray technology, which enables the parallel in-situ electrochemical synthesis of nucleic acids, together with its siRNA Bioinformatic Design Software, enable the design and synthesis of pools of siRNA molecules which can function to effectively silence genes. These pools can be utilized for gene-target discovery and validation efforts, and they can be evaluated as potential drug therapeutics. CombiMatrix is utilizing this platform for initial discovery efforts focused on a selected group of viral diseases (vide infra). The Express Track(sm) platform integrates the following functions:

-- Gene target or pathogen identification

-- Bioinformatic design of sequence libraries

-- Chip-based parallel synthesis of siRNA drug compounds

-- Screening and efficacy validation using CombiMatrix's

customizable gene expression microarrays

After testing for efficacy, the validated pools of HIV siRNA will be screened against the human genome for possible deleterious interactions with endogenous genes using the CombiMatrix custom microarray platform.

Viruses being targeted by CombiMatrix's Express Track(sm) drug discovery platform include:

    Virus                             Collaborator

    SARS                              NIAID/USAMRIID
    HIV type 1                        irsiCaixa-Dr. Bonaventura Clotet

    HIV type 2                        To Be Announced
    West Nile virus                   To Be Announced
    Human Papillomavirus type 16      To Be Announced
    Human Herpes 8 (Kaposi's sarcoma) To Be Announced
    Smallpox (Variola)                To Be Announced
    Influenza virus A                 To Be Announced
    Influenza virus B                 To Be Announced
    Hepatitis C                       To Be Announced
    Leishmania RNA virus              To Be Announced

ABOUT RETROVIROLOGY LABORATORY IRSICAIXA

The irsiCaixa Foundation is a leading institute and reference center for the research and treatment of Acquired Immuno Deficiency Syndrome (AIDS) in Europe. The Foundation was founded in 1995 with the objectives of advocating, inspiring and spreading medical investigation on (AIDS). The irsiCaixa Foundation Scientific Committee includes many world-renowned experts in the field of HIV research (www.irsicaixa.org/english/about/a_stru.html#comite).

The activity of the irsiCaixa Foundation is mainly carried out in the Retrovirology Laboratory of the University Hospital Germans Trias i Pujol in Badalona (Barcelona, Spain). The laboratory director is Dr. Bonaventura Clotet, chief of the AIDS unit of the University Hospital. Dr. Clotet received his M.D. of Medicine and Surgery at the Universitat Autonoma de Barcelona, in 1976. He earned his Ph.D in the investigation of surrogate markers for connective tissue diseases in 1981.

Dr. Clotet has published more than 150 peer-reviewed papers. He is on the Editorial Board of the AIDS Journal and the Journal of the International Association of Physicians in AIDS Care. He has also authored numerous books and chapters on retrovirology and is an expert on siRNA and AIDS.

Professor Clotet is part of the organizing committees of several drug resistance workshops and International Conferences on AIDS, and he is an active member of the Expert Commission for the evaluation of research projects in the National Programme of Health and National AIDS Programme. Dr. Clotet was a co-chair of the Barcelona World AIDS meeting 2002. Information about the irsiCaixa Foundation is available at www.irsicaixa.org.

ABOUT ACACIA RESEARCH CORPORATION

Acacia Research Corporation comprises two operating groups, Acacia Technologies Group and CombiMatrix Group.

The CombiMatrix group is developing a platform technology to rapidly produce customizable active biochips, which are semiconductor-based tools for use in identifying and determining the roles of genes, gene mutations and proteins. CombiMatrix's technology has a wide range of applications including DNA synthesis/diagnostics, drug discovery, and immunochemical detection. CombiMatrix's Express Track(sm) drug discovery program is a systems biology approach, using its technology, to target common viral diseases with siRNA compounds.

The Acacia Technologies group licenses its DMT and V-Chip technologies to media and electronics companies. The DMT technology covers the transmission and receipt of digital audio and digital video content, commonly known as audio on-demand, video on-demand, and audio/video streaming, and is supported by 5 U.S. and 17 international patents.

Acacia Research-Acacia Technologies (Nasdaq:ACTG) and Acacia Research-CombiMatrix (Nasdaq:CBMX) are both classes of common stock issued by Acacia Research Corporation and are intended to reflect the performance of the respective operating groups and are not issued by the operating groups.

Information about Acacia Research Corporation and the Acacia Technologies group is available at www.acaciaresearch.com. Information about the CombiMatrix group is available at www.combimatrix.com.

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