PRAECIS PHARMACEUTICALS INCORPORATED Presents Update on its DirectSelect(TM) Technology

PRAECIS PHARMACEUTICALS INCORPORATED (NASDAQ: PRCS)
today announced that it presented an update on the development of its
DirectSelect(TM) technology at the Drug Discovery Technology Europe
2006 meeting in London, United Kingdom. The Company's presentation was
delivered earlier today by Barry Morgan, Ph.D., Vice President,
Chemistry. Dr. Morgan presented an overview of the development of
DirectSelect(TM) technology, which included a discussion regarding
both the generation of a set of libraries comprising over five billion
compounds geared towards the identification of small molecule drug
candidates, as well as the application of these libraries towards the
identification of hit families to four well-known targets in
proof-of-concept studies. A copy of the presentation has been posted
on the Company's website at http://www.praecis.com under "Investors."

   PRAECIS has developed a chemistry-driven technology, called
DirectSelect(TM), which it believes will facilitate the drug discovery
process. The technology is based upon the creation of multiple,
numerically large (10 to the sixth to >10 to the ninth), encoded
libraries of drug-like structures that can be rapidly screened to
identify individual structures, or families of structures, with
affinity for a macromolecular target.

   The premise behind DirectSelect(TM) is that the odds of
identifying hits with higher affinity and enhanced selectivity for a
macromolecular target can be improved by increasing the numeric size
and "chemical space" interrogated by the target. In addition, access
to multiple, structurally diverse families should improve the
likelihood of identifying a lead molecule with a favorable safety
profile in vivo. Combinatorial libraries of small molecules have
traditionally been constrained to relatively low numbers (up to tens
of thousands) of constituents due to technical limitations associated
largely with deconvolution. PRAECIS has systematically addressed these
challenges by focusing its efforts on marrying validated chemistry
methods with unique screening and deconvolution steps.

   In the presentation, Dr. Morgan described proof-of-concept
screening of the DirectSelect(TM) libraries against three kinase and
one protease target, including the cancer targets Aurora A kinase and
Gleevec-resistant mutant Abl T315I kinase, the inflammation target p38
map kinase, and the Alzheimer's target beta secretase. In each case,
novel hit families were identified and hits were validated through
re-synthesis, without tags used during the library screening, and
testing in biochemical and cell-based assays. These data demonstrate
the broad utility of DirectSelect(TM) to rapidly identify and validate
novel hit families to pharmaceutical targets in approximately a one
month time frame.

   Given the successful internal validation of the ability of this
technology to identify hit molecules in the proof-of-concept studies
referenced above, PRAECIS has initiated activities to screen for new
compounds against therapeutic targets of interest. The continued
development and enhancement of DirectSelect(TM) is an important
component of PRAECIS' strategic operating plan, and PRAECIS believes
that this technology may be an important tool for the future of drug
discovery and development. The Company intends to use its
DirectSelect(TM) technology to support pharmaceutical partnerships in
drug discovery and development, and continues to initiate and advance
research collaboration discussions with various major pharmaceutical
companies with respect to this technology. The Company also intends to
use this technology to expand its own proprietary development
pipeline.

   About PRAECIS

   PRAECIS PHARMACEUTICALS INCORPORATED is a biopharmaceutical
company focused on the discovery and development of novel compounds
with 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 seeking partnerships
relating to, as well as the internal use of, its DirectSelect(TM)
technology. 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 continue
development of and successfully partner its DirectSelect(TM)
technology, 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
September 30, 2005. 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.