CombiMatrix Receives $1,250,000 Payment in Strategic Alliance with Toppan.

Business Editors/Health/Medical Writers

NEWPORT BEACH, Calif.--(BUSINESS WIRE)--Dec. 2, 2003

Acacia Research Corporation (Nasdaq:CBMX)(Nasdaq:ACTG) announced today its CombiMatrix Group has achieved a milestone in its multi-year strategic alliance with Toppan, resulting in a $1,250,000 payment. CombiMatrix received an initial $1 million upfront payment in May of this year from Toppan when the alliance was formed.

"We are working with Toppan to develop a microarray product suite based on our proprietary electrochemical detection approach," said Amit Kumar, Ph.D., President and Chief Executive Officer of CombiMatrix. "This approach should enable smaller and less expensive detection instrumentation and potential improvement of performance characteristics over conventional microarrays, which use optical methods for detection. The first application of these microarrays may be for biological and chemical warfare agent detection followed by broader life science applications."

Under the terms of the agreement, CombiMatrix and Toppan are co-developing semiconductor microarrays for applications in life science research, biological and chemical warfare agent detection, as well as diagnostics. Upon commercialization, Toppan will manufacture microarrays for CombiMatrix or its partners and will share revenues and royalties on these products.

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 initial focus of Express Track(SM) are the following viral diseases:

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

    CombiMatrix is also establishing applications of its arrays
through other partnerships as follows:

Project                               Collaborator

Cancer Diagnosis (Lymphoma)           University of Washington/
                                       Rational Diagnostics
RNA Drug Targets                      Professor Gregory L. Verdine,
                                       Harvard University
Parasite

Leishmania                            Seattle Biomedical Research
                                       Institute
Trypasonoma                           Seattle Biomedical Research
                                       Institute

The Acacia Technologies group licenses its Digital Media Transmission (DMT) technology 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.

Safe Harbor Statement under the Private Securities Litigation Reform Act of 1995:

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 recent 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.