PRAECIS PHARMACEUTICALS INCORPORATED Reports First Quarter 2006 Financial Results

PRAECIS PHARMACEUTICALS INCORPORATED (NASDAQ: PRCS)
today announced consolidated financial results for the three months
ended March 31, 2006.

   First Quarter 2006 Results

   The Company's net loss for the three months ended March 31, 2006
was approximately $7,052,000, or $0.67 per diluted share, compared to
a net loss of approximately $12,345,000, or $1.18 per diluted share,
for the three months ended March 31, 2005.

   The decreased net loss for the three months ended March 31, 2006,
compared to the three months ended March 31, 2005, was due primarily
to reduced expenses resulting from the Company's strategic
restructuring announced in May 2005. These expense reductions related
principally to the voluntary discontinuation of promotional activities
for Plenaxis(R) in the United States and a significant headcount
reduction in May 2005. Expenses incurred during the first quarter of
2006 related primarily to the advancement of the Company's
DirectSelect(TM) drug discovery technology. Other expenses were
related to clinical development of the Company's investigational
compound, PPI-2458, other research, and general and administrative
expenses. The decrease in expenses for the three months ended March
31, 2006 was somewhat offset by approximately $872,000 of incremental
non-cash compensation expense associated with the Company's adoption
of Financial Accounting Standards Board Statement No. 123R,
Share-Based Payment (SFAS No. 123R). Of this amount, approximately
$647,000 of compensation expense associated with equity-based
compensation plans was allocated to research and development expense,
and approximately $225,000 of such compensation expense was allocated
to general and administrative expense.

   At March 31, 2006, the Company had cash, cash equivalents and
marketable securities of $52,718,000, compared to approximately
$62,580,000 at December 31, 2005. As previously disclosed, in January
2006, the Company made a cash payment of $1,630,000 under a
manufacturing contract as part of an agreement to suspend a
manufacturing campaign, as well as certain manufacturing activities
related to Plenaxis(R). The Company had initiated the manufacturing
campaign prior to the strategic restructuring announced in May 2005
and accordingly, had included this commitment as part of its
restructuring charges during 2005.

   Commenting on the activities for the quarter, Kevin F. McLaughlin,
PRAECIS' President and Chief Executive Officer stated, "We are
focusing our research and development efforts on advancing our
PPI-2458 clinical program and on applying our DirectSelect(TM) drug
discovery technology to both internal and external programs. PPI-2458
continues to progress through a phase I clinical trial in patients
with non-Hodgkin's lymphoma and solid tumors. Our goal is to present
interim data from our phase 1 trial during the fourth quarter of 2006.
Ongoing research continues to strengthen the preclinical rationale for
the use of PPI-2458 as a targeted molecular therapy in a variety of
oncology indications, including those currently being studied, as well
as melanoma. In addition, positive results in a number of preclinical
efficacy models appear to support this compound's potential in
inflammatory and autoimmune disorders, specifically Rheumatoid
Arthritis, and therefore, we are investigating various strategic
partnering and clinical development alternatives for PPI-2458 in these
indications.

   "With respect to our DirectSelect(TM) technology, we have made
considerable progress at both the scientific and business level during
the last quarter. Our strategic vision for this innovative technology
is to use it to develop lead compounds directed to carefully chosen
internal targets, and to leverage the broad capability of the
technology through corporate alliances. Towards the latter goal,
during the last six weeks we signed pilot agreements with Gilead
Sciences, Inc. and GlaxoSmithKline. These are intended to be early
technology validation partnerships with potential future value to the
Company as the technology proves itself to the partner. We intend to
seek partnering deals of greater value to the Company with major
biotechnology and pharmaceutical companies. To spearhead this effort,
we have recently hired an experienced business development person, Dr.
Prem Das, as Senior Vice President, Technology Partnerships. Dr. Das
most recently had responsibility for overseeing out-licensing
negotiations for the Office of Technology Development at Harvard
Medical School.

   "We are also applying DirectSelect(TM) technology internally to a
number of potential therapeutic targets. As previously disclosed, we
have applied DirectSelect(TM) to the kinase targets - Aurora A kinase,
p38 MAP kinase and Abl kinase (wild type and variants), and to the
protease - beta-secretase (BACE), an Alzheimer's target. We have
identified several series of inhibitors to these targets and are
currently working on optimizing these initial inhibitors by
constructing focused "secondary" libraries. Using these focused
libraries, our goal is to continue working toward identifying a
compound, or potentially families of compounds, which have improved
characteristics over the initial inhibitors and which qualify as leads
for therapeutic development."

   Mr. McLaughlin continued, "In addition to developing
DirectSelect(TM) libraries for secondary screening, we are also
advancing our DirectSelect(TM) technology on various other fronts. We
continue to engineer additional DirectSelect(TM) libraries using novel
chemical scaffolds. We are also adapting DirectSelect(TM) to
incorporate drug fragment techniques, working out novel aqueous
chemistries and two-phase reactions to expand the chemistry repertoire
and exploring the ability of the technology to tackle difficult
targets, including those involved in protein: protein interactions.

   "DirectSelect(TM) continues to be a major part of our business
model moving forward. By developing a powerful, cost-effective drug
discovery capability, the Company will be able to rapidly diversify
its portfolio of drug candidates and, therefore, more effectively
manage the risks of drug development inherently associated with any
individual program. The key to our ongoing success is to use
DirectSelect(TM) to identify multiple lead families of molecules to
any target of interest. This will allow for the best candidates to be
selected for development with the least toxic effects, for us and
future partners."

   Concluding his comments, Mr. McLaughlin stated, "With regard to
Plenaxis(R), as we have previously announced, we are actively pursuing
with the assistance of an investment banking firm, the disposition of
this asset through a license or sale transaction and, to date, a
number of parties have evaluated the opportunity. Our goal is to
announce the conclusion of this process by the end of the second
quarter of 2006."

   There will be a conference call to discuss this press release
today beginning at 9:00 a.m. (EDT). This call will be broadcast live
over the Internet at www.praecis.com under "Investor Relations." A
telephonic replay of this call will be available beginning at 12:00
Noon (EDT), until midnight Friday, May 12, 2006, by calling
888-203-1112 (domestic toll-free) or 719-457-0820, and entering the
passcode 6614522. This press release, including the financial results
relating to PRAECIS' first quarter ended March 31, 2006, are also
available on PRAECIS' web site under "News Center."

   The Company is planning to report second quarter 2006 results on
August 4, 2006. For information regarding live webcasts and investment
community conference calls related to second quarter 2006 results,
please refer to www.praecis.com approximately one week prior to the
financial reporting release date.

   About PRAECIS

   PRAECIS PHARMACEUTICALS INCORPORATED is a biopharmaceutical
company focused on the discovery and development of novel compounds
that have the potential to address unmet medical needs or improve
existing therapies. PRAECIS has a novel MetAP-2 inhibitor, PPI-2458,
in clinical development for cancer indications, including
non-Hodgkin's lymphoma and solid tumors, as well as an innovative drug
discovery technology, DirectSelect(TM), which enables the generation
and practical use of ultra-large libraries for the discovery of orally
active compounds for drug development. PRAECIS has received approval
to market Plenaxis(R) in both the United States and Germany.

   This news release contains forward-looking statements, including
statements regarding the Company's plans for the continued clinical
development of, and the potential timing of disclosure of clinical
trial results related to, PPI-2458, seeking partnerships relating to,
as well as the internal use in certain programs of, the Company's
DirectSelect(TM) technology, and the Company's efforts to dispose of
its Plenaxis(R) assets through a license or sale transaction. These
statements are based on the Company's current beliefs and expectations
as to future outcomes and are not guarantees of future events or
performance. These statements are subject to numerous risks,
uncertainties and assumptions that could cause actual events and
results to differ from those anticipated or projected, including, but
not limited to, the Company's ability to manage operating expenses,
unexpected expenditures, the interest of, and financial and other
terms required by, other parties with respect to a possible license or
sale transaction relating to Plenaxis(R), the Company's ability to
continue development of and successfully partner its DirectSelect(TM)
technology and PPI-2458, the Company's ability to successfully perform
under its DirectSelect(TM) pilot study agreements, unexpected results
in ongoing and future clinical or preclinical trials, and the need for
additional research and testing, including as a result of
unanticipated determinations by regulatory authorities, as well as the
risks set forth from time to time in the Company's filings with the
Securities and Exchange Commission, including but not limited to the
various risks discussed in the Company's Quarterly Report on Form 10-Q
for the quarter ended March 31, 2006. The Company undertakes no
obligation to update any forward-looking statement made in this press
release to reflect new information, events or circumstances after the
date of this release.

   Plenaxis(R) is a registered trademark of PRAECIS PHARMACEUTICALS
INCORPORATED.
-0-
*T
                 PRAECIS PHARMACEUTICALS INCORPORATED
            Condensed Consolidated Statements of Operations
                 (in thousands, except per share data)
                              (unaudited)

                                                    Three Months Ended
                                                         March 31,
                                                    ------------------
                                                       2005     2006
                                                     --------  -------

Revenues:
    Product sales                                   $    804  $   136
    Licensing and other revenues                          77       35
                                                     --------  -------
        Total revenues                                   881      171

Costs and expenses:
    Cost of goods sold                                   181       57
    Research and development                           7,283    6,417
    Sales and marketing                                3,657        -
    General and administrative                         1,978    1,845
    Restructuring and asset impairment                     -     (497)
                                                     --------  -------
        Total costs and expenses                      13,099    7,822
                                                     --------  -------

Operating loss                                       (12,218)  (7,651)

Interest (expense) income, net                          (127)     599
                                                     --------  -------

Net loss                                            $(12,345) $(7,052)
                                                     ========  =======

Basic and diluted net loss per common share         $  (1.18) $ (0.67)
                                                     ========  =======

Weighted average number of basic and diluted common
 shares outstanding                                   10,485   10,505



                 PRAECIS PHARMACEUTICALS INCORPORATED
                 Condensed Consolidated Balance Sheets
                            (in thousands)
                              (unaudited)

                                                     December   March
                                                        31,      31,
                                                       2005     2006
                                                     -------- --------

Cash and cash equivalents                            $57,088  $49,206
Marketable securities                                  5,492    3,512
Accounts receivable and other current assets           1,080    1,005
Net fixed assets                                       3,559    3,895
Inventory and other long-term assets                   2,325    2,325
                                                      -------  -------

     Total assets                                    $69,544  $59,943
                                                      =======  =======

Current liabilities                                  $ 9,579  $ 7,059
Long-term liabilities                                  8,802    7,786
Total stockholders' equity                            51,163   45,098
                                                      -------  -------

     Total liabilities and stockholders' equity      $69,544  $59,943
                                                      =======  =======
*T