CAMBRIDGE, MA — August 30, 2005 – Momenta Pharmaceuticals, Inc. (Nasdaq: MNTA), announced today that an Abbreviated New Drug Application (ANDA) seeking marketing approval of M-Enoxaparin has been filed with the United States Food and Drug Administration (FDA). Momenta is developing M-Enoxaparin, a technology-enabled generic version of Lovenox®, in collaboration with Sandoz, the generics division of Novartis AG.

Approved for the prevention and treatment of deep vein thrombosis and treatment of acute coronary syndromes, Lovenox (enoxaparin sodium injection) is a widely-prescribed low molecular weight heparin. Sanofi-Aventis reported worldwide Lovenox sales of $2.4 billion in 2004.

“The ANDA for M-Enoxaparin is a major accomplishment for Momenta, representing the first application for marketing approval filed with the FDA based upon our technology,” said Alan Crane, Chief Executive Officer of the Company. “We believe that our proprietary approach to characterizing and sequencing complex sugars can be applied to both the development of generic versions of complex drugs as well as to the discovery and development of novel products based on sugars.”

Under the FDA’s ANDA requirements, a generic drug must be shown to have, among other things, the same active ingredients as the innovator product upon which the generic application is based. Like other low molecular weight heparins, Lovenox consists of a heterogeneous mixture of complex sugar chains. “We believe that our proprietary technology enables us to analyze the Lovenox mixture and demonstrate that M-Enoxaparin has the same active ingredients as Lovenox,” said Mr. Crane.

About Momenta
Momenta Pharmaceuticals, Inc. is a biotechnology company specializing in the sequencing, or detailed structural analysis, and design of complex sugars for the development of novel drugs, the improvement of existing drugs and the discovery of new biological processes. Momenta is also utilizing its characterization technology to create technology-enabled generic versions of complex and biologic drug products. Based on its understanding of complex sugars, Momenta has created a diversified pipeline of near-term product opportunities, novel development products and discovery candidates. Momenta was founded in 2001 and is headquartered in Cambridge, MA.

Forward Looking Statements
Statements in this press release regarding Momenta Pharmaceuticals Inc.’s future expectations, beliefs, goals, intentions, strategies, plans or prospects, including statements relating to the likelihood of approval of its ANDA filing for M-Enoxaparin, future commercialization efforts of M-Enoxaparin, corporate and development strategies and future development programs, may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Momenta’s actual results could differ materially from those stated or implied in forward-looking statements due to a number of factors, including those factors contained in Momenta’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2005 filed with the Securities and Exchange Commission under the section “Risk Factors That May Affect Results,” as well as other documents that may be filed by Momenta from time to time with the Securities and Exchange Commission. Forward-looking statements include statements regarding Momenta’s expectations, beliefs, goals, intentions, strategies, plans or prospects regarding the future and can be identified by forward-looking words such as “anticipate”, “believe”, “could”, “estimate”, “expect”, “intend”, “may”, “should”, “will”, and “would” or similar terms, variations of such terms or the negative of such terms. Momenta assumes no obligations to update the information included in this press release as a result of new information, future events or otherwise.

Our logo, trademarks, and service marks are the property of Momenta Pharmaceuticals, Inc. Lovenox® is a registered trademark of Aventis Pharma S.A. All other trade names, trademarks, or service marks are property of their respective owners.

Investor Contact:
Michael A. Lawless
Momenta Pharmaceuticals, Inc.
617-395-5189

Media Contact:
Kathryn Morris
Kathryn Morris PR
845-635-9828

Press Contact
press@momentapharma.com

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