CAMBRIDGE, MA — March 17, 2005 – Momenta Pharmaceuticals, Inc. (Nasdaq: MNTA), a biotechnology company developing drugs based on its proprietary sugar sequencing technology, announced today that Marsha Fanucci has been elected to Momenta’s Board of Directors, replacing John Zabriskie, Ph.D.

“I am extremely pleased to have Marsha join our Board. Her experience in finance, corporate strategy and business development will make her a valuable resource for us as we transition into a commercial entity. Our technology platform for sequencing and engineering complex sugars has broad product application, and we expect that she will help us to evaluate the commercial potential of our strategies,” said Alan Crane, Chief Executive Officer of Momenta.

Ms. Fanucci is presently Senior Vice President and Chief Financial Officer of Millennium Pharmaceuticals, Inc., where she is responsible for corporate strategy, treasury, financial planning and reporting, and information technology. Since joining Millennium in 2000, she has also served in roles that included mergers and acquisitions, and licensing. Previously, she was Vice President of Corporate Development and Strategy at Genzyme. Ms. Fanucci has also served as Vice President and Managing Director at Arthur D. Little Inc. She received her Bachelor of Science degree in Pharmacy from West Virginia University and her Masters in Business Administration from Northeastern University.

“I want to thank John Zabriskie for his many contributions to Momenta,” continued Mr. Crane. “He has played an important role in our dramatic progress from a small, private, development stage company to our present position as a public company with exciting near-term product opportunities. The Board of Directors wishes him the very best in his future endeavors.”

About Momenta
Momenta Pharmaceuticals, Inc. is a biotechnology company specializing in the sequencing and engineering of complex sugars for the development of improved versions of existing drugs, the development of novel drugs and the discovery of new biological processes. Momenta is also utilizing its ability to sequence sugars to create technology-enabled generic products. The Company’s most advanced product candidate is M-Enoxaparin, a technology-enabled generic version of Lovenox®. Based on its understanding of complex sugars, Momenta has created a diversified pipeline of novel discovery and development candidates. Momenta was founded in 2001 and is headquartered in Cambridge, MA.

To receive additional information about Momenta, please visit our website at www.momentapharma.com, which does not form a part of this press release.

Forward Looking Statements
Statements in this press release regarding Momenta Pharmaceuticals Inc.’s future expectations, beliefs, goals, plans or prospects 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 final prospectus dated June 21, 2004 filed with the Securities and Exchange Commission in connection with Momenta’s initial public offering under the section “Risk Factors,” 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, intentions or strategies 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 words. Momenta assumes no obligations to update the information included in this press release.

Our logo, trademarks, and service marks are the property of Momenta Pharmaceuticals, Inc. All other trade names, trademarks, or service marks are property of their respective owners and are not the property of Momenta Pharmaceuticals, Inc.

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

Press Contact
press@momentapharma.com

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