CombiMatrix and Oklahoma State University Collaborate on Influenza A 'Bird Flu' Research Program.

Business Editors/Health/Medical Writers

BIOWIRE2K

NEWPORT BEACH, Calif.--(BUSINESS WIRE)--March 26, 2004

Acacia Research Corporation (Nasdaq:CBMX)(Nasdaq:ACTG) announced today that Dr. Ulrich Melcher, Department of Biochemistry & Molecular Biology and Dr. Alexander C. Lai, Department of Microbiology and Molecular Genetics, from Oklahoma State University, will utilize CombiMatrix's 'Bird Flu' CustomArray(TM) devices to characterize influenza A viruses at the genomic level. One goal of this project is to speed the development of better identification and characterization methods for influenza viruses.

CombiMatrix's 'Bird Flu' arrays will be utilized by Drs. Melcher and Lai to study and characterize various strains of the human and avian flu viruses for rapid typing of a wide range of subtypes from H1 to H15 and N1 to N8. Drs. Melcher and Lai's work in the characterization of influenza virus strains by microarrays was recently published in the Journal of Clinical Microbiology.

"The CombiMatrix Influenza A arrays will help to accelerate our research in identifying and characterizing the key differences in the avian flu strains. The data from these arrays will provide important information which will enable us to advance our research efforts," said Dr. Melcher. "These arrays should allow us to better understand the strains of Avian Flu that are most dangerous to humans and help us move towards development of diagnostics and therapeutics."

"CombiMatrix's 'Bird Flu' array and its proprietary content joins a growing list of viral arrays being developed and used by researchers to study emerging diseases," said Dr. Amit Kumar, President and CEO of CombiMatrix. "Using our CustomArray(TM) line of products, researchers can design arrays to include any sequence from multiple pathogens all on the same chip. Rapid redesign of our arrays provides researchers with the necessary tools to study emerging infectious diseases. This program is synergistic with our work with St. Jude Children's Research Hospital."

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, siRNA synthesis, drug discovery, and immunochemical detection. CombiMatrix provides DNA arrays to researchers under the CustomArray(TM) brand. 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 develops, acquires, and licenses patented technologies. Acacia's DMT technology, which is supported by 5 U.S. and 31 foreign patents, relates to audio and audio/video transmission and receiving systems commonly known as audio-on-demand, video-on-demand, and audio/video streaming, and is used for distributing digital content via several means including Internet, cable, satellite and wireless systems.

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 the Acacia Technologies Group and the CombiMatrix Group is available at www.acaciaresearch.com.

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This news release contains forward-looking statements within the meaning of the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. These statements are based upon our current expectations and speak only as of the date hereof. Our actual results may differ materially and adversely from those expressed in any forward-looking statements as a result of various factors and uncertainties, including the economic slowdown affecting technology companies, our ability to successfully develop products, rapid technological change in our markets, changes in demand for our future products, legislative, regulatory and competitive developments and general economic conditions. Our Annual Report on Form 10-K, recent and forthcoming Quarterly Reports on Form 10-Q, recent Current Reports on Forms 8-K and 8-K/A, and other SEC filings discuss some of the important risk factors that may affect our business, results of operations and financial condition. We undertake no obligation to revise or update publicly any forward-looking statements for any reason.