PRAECIS PHARMACEUTICALS INCORPORATED Presents Preclinical Data on PPI-2458

  
    
  
  
    
      PRAECIS PHARMACEUTICALS INCORPORATED (NASDAQ: PRCS) today announced that 
      it is presenting preclinical data on its investigational compound, 
      PPI-2458, at the 14th International 
      Inflammation Research Association Conference being held in Cambridge, 
      Maryland. The Company’s presentation, entitled “Disease-modifying 
      activity in a model of rheumatoid arthritis with an orally available 
      inhibitor of methionine aminopeptidase type-2, PPI-2458,” 
      will be delivered by William Westlin, Ph.D., Senior Vice President, 
      Preclinical Research today at 3:00 p.m., EDT. Dr. Westlin will present 
      preclinical data that provide rationale for studying the investigational 
      compound PPI-2458 as a targeted molecular therapy for rheumatoid 
      arthritis. A copy of the presentation will be posted on the Company’s 
      website at http://www.praecis.com, 
      under “Investors” 
      following the presentation.
    
    
      PPI-2458 is a novel, proprietary, orally available small molecule that 
      specifically targets the enzyme, methionine aminopeptidase-2 (MetAP-2). 
      Inhibition of MetAP-2 by PPI-2458 has been demonstrated in extensive 
      preclinical evaluations to inhibit angiogenesis and the proliferation of 
      human rheumatoid arthritis synovial cells that contribute to the 
      pathogenesis of the human disease. The Company’s 
      presentation highlights new mechanism of action data that demonstrates 
      significant protective effects of PPI-2458 on bone and cartilage 
      destruction. Data also will be presented demonstrating the effects of 
      PPI-2458 on osteoclasts, cells that produce the erosive deformities that 
      occur in the human rheumatoid arthritis condition. In animal models of 
      rheumatoid arthritis, PPI-2458 displays disease-modifying activity, 
      including protection from chronic inflammation and prevention of 
      structural damage in affected joints. The results from these preclinical 
      models provide support for the clinical investigation of PPI-2458 in 
      rheumatoid arthritis patients, and the Company is evaluating the 
      potential initiation of clinical studies in this indication.
    
    
      PRAECIS also is conducting a Phase 1 clinical study of PPI-2458 in 
      cancer patients. The study is designed to assess the safety and 
      tolerability of orally administered PPI-2458. As a secondary endpoint, 
      the study will assess the pharmacodynamic activity of PPI-2458. Interim 
      data from this clinical trial will be presented at the upcoming 18th 
      EORTC-NCI-AACR Symposium on “Molecular Targets 
      and Cancer Therapeutics” being held from 
      Tuesday, November 7 to Friday, November 10, 2006 at the Prague Congress 
      Centre in Prague, Czech Republic. Additional information about the 
      Company’s ongoing clinical trial for PPI-2458 
      can be accessed on the Internet at www.clinicaltrials.gov. 
      The Company is currently planning its Phase 2 clinical development 
      protocols in oncology.
    
    
      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™, 
      which enables the generation and practical use of ultra-large libraries 
      for the discovery of orally active compounds for drug development.
    
    
      This news release contains forward-looking statements regarding the 
      Company’s continued development of PPI-2458 
      for cancer and autoimmune disorders. These statements are based on the 
      Company’s current beliefs and expectations as 
      to future outcomes and are not guarantees of such outcomes or of future 
      performance. These statements are subject to numerous risks, 
      uncertainties and assumptions that could cause actual events and results 
      to differ from those expected or anticipated, including, but not limited 
      to, the Company’s ability to continue 
      development of and successfully partner or otherwise obtain funding for 
      its PPI-2458 program, the Company’s ability 
      to continue to manage operating expenses and to retain key employees, 
      unexpected expenditures, the timing and content of decisions made by the 
      FDA, 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 June 30, 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.
    
  
PRAECIS PHARMACEUTICALS INCORPORATED (NASDAQ: PRCS) today
announced that it is presenting preclinical data on its
investigational compound, PPI-2458, at the 14th International
Inflammation Research Association Conference being held in Cambridge,
Maryland. The Company's presentation, entitled "Disease-modifying
activity in a model of rheumatoid arthritis with an orally available
inhibitor of methionine aminopeptidase type-2, PPI-2458," will be
delivered by William Westlin, Ph.D., Senior Vice President,
Preclinical Research today at 3:00 p.m., EDT. Dr. Westlin will present
preclinical data that provide rationale for studying the
investigational compound PPI-2458 as a targeted molecular therapy for
rheumatoid arthritis. A copy of the presentation will be posted on the
Company's website at http://www.praecis.com, under "Investors"
following the presentation.

   PPI-2458 is a novel, proprietary, orally available small molecule
that specifically targets the enzyme, methionine aminopeptidase-2
(MetAP-2). Inhibition of MetAP-2 by PPI-2458 has been demonstrated in
extensive preclinical evaluations to inhibit angiogenesis and the
proliferation of human rheumatoid arthritis synovial cells that
contribute to the pathogenesis of the human disease. The Company's
presentation highlights new mechanism of action data that demonstrates
significant protective effects of PPI-2458 on bone and cartilage
destruction. Data also will be presented demonstrating the effects of
PPI-2458 on osteoclasts, cells that produce the erosive deformities
that occur in the human rheumatoid arthritis condition. In animal
models of rheumatoid arthritis, PPI-2458 displays disease-modifying
activity, including protection from chronic inflammation and
prevention of structural damage in affected joints. The results from
these preclinical models provide support for the clinical
investigation of PPI-2458 in rheumatoid arthritis patients, and the
Company is evaluating the potential initiation of clinical studies in
this indication.

   PRAECIS also is conducting a Phase 1 clinical study of PPI-2458 in
cancer patients. The study is designed to assess the safety and
tolerability of orally administered PPI-2458. As a secondary endpoint,
the study will assess the pharmacodynamic activity of PPI-2458.
Interim data from this clinical trial will be presented at the
upcoming 18th EORTC-NCI-AACR Symposium on "Molecular Targets and
Cancer Therapeutics" being held from Tuesday, November 7 to Friday,
November 10, 2006 at the Prague Congress Centre in Prague, Czech
Republic. Additional information about the Company's ongoing clinical
trial for PPI-2458 can be accessed on the Internet at
www.clinicaltrials.gov. The Company is currently planning its Phase 2
clinical development protocols in oncology.

   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.

   This news release contains forward-looking statements regarding
the Company's continued development of PPI-2458 for cancer and
autoimmune disorders. These statements are based on the Company's
current beliefs and expectations as to future outcomes and are not
guarantees of such outcomes or of future performance. These statements
are subject to numerous risks, uncertainties and assumptions that
could cause actual events and results to differ from those expected or
anticipated, including, but not limited to, the Company's ability to
continue development of and successfully partner or otherwise obtain
funding for its PPI-2458 program, the Company's ability to continue to
manage operating expenses and to retain key employees, unexpected
expenditures, the timing and content of decisions made by the FDA,
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 June 30, 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.