Clinical Data to Acquire Genaissance Pharmaceuticals; Combined Company to Deliver Industry-Defining Theranostics

Clinical Data, Inc. (NASDAQ:CLDA) and Genaissance
Pharmaceuticals, Inc. (NASDAQ:GNSC) today announced that they have
signed an agreement for Clinical Data to acquire Genaissance
Pharmaceuticals in an all-stock transaction valued at approximately
$56 million. The merger will marry the skills and capabilities of a
classic diagnostic company with a leader in the promising area of
pharmacogenomics, creating a combined company that will offer a unique
opportunity to enter the molecular diagnostics market.
   Israel M. Stein, MD, President and Chief Executive Officer of
Clinical Data commented, "Genaissance Pharmaceuticals is a strong
strategic fit, enabling us to enter the molecular diagnostics market
in a meaningful way. Genaissance currently has two clinically relevant
molecular diagnostic tests available commercially and additional
developmental opportunities in the CNS and cardiovascular area. We
believe the acquisition will allow us to leverage our market knowledge
and experience with GNSC's platform to become a leading
pharmacogenomics company with high margin, proprietary tests and
services serving broad markets."
   Dr. Stein continued, "Guiding pharmaceutical therapy through the
use of diagnostic tests, also known as "theranostics," requires the
integration of regulatory, research, clinical and marketing
approaches. We strongly believe the benefits of genetically targeted
pharmacotherapy will become essential to disease prevention and
treatment."
   Under the terms of the agreement, which has been unanimously
approved by both boards of directors, GNSC stockholders will receive,
at a fixed exchange ratio, 0.065 shares of CLDA common stock for each
share of GNSC common stock in a tax-free exchange. Based on CLDA's and
GNSC's closing prices on Monday, June 20, this represents a price of
$1.33 per share of GNSC common stock. GNSC preferred shareholders will
exchange their shares for Clinical Data preferred shares. As such and
upon the close of the transaction, GNSC common and preferred
shareholders will own approximately forty percent (40%) of the
combined company. The transaction is subject to certain customary
conditions and is expected to close in the fourth calendar quarter.
   Upon completion of the acquisition, current Genaissance board
members Kevin Rakin and Joseph "Skip" Klein III will join CLDA's board
of directors. Burton E. Sobel, MD, E.L. Amidon Professor,
Physician-in-Chief, and Professor of Biochemistry at the University of
Vermont, will also join the Board, bringing the total number of
directors to seven.
   Kevin Rakin, Chief Executive Officer of Genaissance
Pharmaceuticals stated, "Genaissance is aligning itself with a
financially stable company, enabling us to integrate our
pharmacogenomics products and services with a well established company
in the development and marketing of medical diagnostics. CLDA's strong
infrastructure, regulatory experience and marketing prowess will allow
us to deliver on the potential of our technology while participating
in the growth of a well established, core business."
   The combined company will be profit driven, operate domestically
and internationally, and will offer a wide range of reagents,
instruments and molecular testing services directed at the physician
office and hospital markets. The Company's DNA and pharmacogenomics
services will continue to be marketed to the pharmaceutical,
biotechnology and agricultural marketplaces.
   Randal J. Kirk, Chairman of Clinical Data said, "Pharmacogenomics
is poised to play a significant role in healthcare and is a growing
area of research that is gaining traction with pharmaceutical
companies and clinicians. Through this acquisition, CLDA is building
on its strong existing foundation to enter new markets and continue to
be an innovator in improving patient healthcare."
   As financial advisor to Clinical Data, WR Hambrecht + Co rendered
a fairness opinion to the Board of Directors in connection with this
transaction. CIBC World Markets Corp. acted as exclusive financial
advisor to Genaissance Pharmaceuticals, Inc. in this transaction.

   Important Additional Information will be Filed with the SEC

   Clinical Data plans to file with the SEC a Registration Statement
on Form S-4 in connection with the transaction and Clinical Data and
Genaissance plan to file with the SEC and mail to their respective
stockholders a Joint Proxy Statement/Prospectus in connection with the
transaction. The Registration Statement and the Joint Proxy
Statement/Prospectus will contain important information about Clinical
Data, Genaissance, the transaction and related matters. Investors and
security holders are urged to read the Registration Statement and the
Joint Proxy Statement/Prospectus carefully when they are available.
   Investors and security holders will be able to obtain free copies
of the Registration Statement and the Joint Proxy Statement/Prospectus
and other documents filed with the SEC by Clinical Data and
Genaissance through the web site maintained by the SEC at www.sec.gov.
   In addition, investors and security holders will be able to obtain
free copies of the Registration Statement and the Joint Proxy
Statement/Prospectus from Clinical Data by contacting Mark D. Shooman
or from Genaissance by contacting Marcia Passavant.
   Clinical Data and Genaissance, and their respective directors and
executive officers, may be deemed to be participants in the
solicitation of proxies in respect of the transactions contemplated by
the merger agreement. Information regarding Clinical Data's directors
and executive officers is contained in Clinical Data's Form 10-KSB for
the year ended March 31, 2004 and its proxy statement dated August 13,
2004, which are filed with the SEC. As of June 17, 2005, Clinical
Data's directors and executive officers beneficially owned
approximately 3,709,680 shares, or 81.7%, of Clinical Data's common
stock. Information regarding Genaissance's directors and executive
officers is contained in Genaissance's Form 10-K for the year ended
December 31, 2004 and its proxy statement dated April 8, 2005, which
are filed with the SEC. As reported in Genaissance's proxy statement,
Genaissance's directors and executive officers beneficially owned
approximately 3,446,987 shares, or 9.43%, of Genaissance's common
stock. A more complete description will be available in the
Registration Statement and the Joint Proxy Statement/Prospectus.

   About Genaissance Pharmaceuticals, Inc.

   Genaissance Pharmaceuticals, Inc. is a leader in the discovery and
use of human gene variation for the development of a new generation of
DNA-based diagnostic and therapeutic products. The Company's
technology, services and clinical development expertise are marketed
to biopharmaceutical and diagnostic development companies, as a
comprehensive solution to their pharmacogenomic needs. The Company's
goal is to improve drug development, physicians' ability to prescribe
drugs, and patients' lives by elucidating the role of genetic
variation in drug response. Additionally, the Company provides Good
Laboratory Practices (GLP) compliant DNA banking and research and GLP
compliant genotyping and related services to a variety of companies.

   About Clinical Data, Inc.

   Clinical Data, Inc., established in 1972, through its domestic and
foreign subsidiaries, focuses on the needs of physician offices and
smaller clinical laboratories. The Company provides a complete range
of products and consulting services to the growing physician office
laboratory market and offers blood chemistry instrumentation and
diagnostic assays to clinics and small hospitals worldwide.

   SAFE HARBOR STATEMENT UNDER THE PRIVATE SECURITIES LITIGATION
REFORM ACT OF 1995

   This press release contains certain forward-looking information
about the transactions that are intended to be covered by the safe
harbor for "forward-looking statements" provided by the Private
Securities Litigation Reform Act of 1995. Forward-looking statements
are statements that are not historical facts. Words such as
"expect(s)", "feel(s)", "believe(s)", "will", "may", "anticipate(s)"
and similar expressions are intended to identify forward-looking
statements. These statements include, but are not limited to
statements regarding: our ability to successfully integrate the
operations, business and technology of GNSC; our ability to expand our
long-term business opportunities; our ability to maintain normal terms
with GNSC's customers and partners; the expected effects and benefits
of the acquisition; financial projections and estimates and their
underlying assumptions; statements regarding plans, objectives and
expectations with respect to integrating GNSC, future operations,
products and services; the expected benefits and opportunities of
pharmacogenomics; and statements regarding future performance. Such
statements are subject to certain risks and uncertainties, many of
which are difficult to predict and generally beyond the control of the
Company, that could cause actual results to differ materially from
those expressed in, or implied or projected by, the forward-looking
information and statements. These risks and uncertainties include: our
ability to consummate CLDA's acquisition of GNSC, our ability to
achieve expected synergies and operating efficiencies in the
acquisition and to successfully integrate our operations; our
expectations regarding the timing, completion and accounting and tax
treatments of the transactions and the value of the transaction
consideration; our ability to maintain normal relations with GNSC's
partners and customers; the development of and our ability to take
advantage of the market for pharmacogenomic products and services;
general economic downturns; and other risks contained in CLDA's
various SEC reports, including but not limited to its Annual Report on
Form 10-KSB for the fiscal year ended March 31, 2004, and the 2004 and
2005 quarterly Form 10-QSB filings, and in GNSC's Annual Report on
Form 10-K for the fiscal year ended December 31, 2004. Readers are
cautioned not to place undue reliance on these forward-looking
statements that speak only as of the date hereof. CLDA does not
undertake any obligation to republish revised forward-looking
statements to reflect events or circumstances after the date hereof or
to reflect the occurrence of unanticipated events.