NxStage Completes Final Closing of Previously Announced Private Placement of Common Stock

Friday August 1, 2008

LAWRENCE, Mass., Aug. 1 /PRNewswire-FirstCall/ — NxStage Medical, Inc. (Nasdaq: NXTM), a leading manufacturer of innovative dialysis products, announced today that it has completed its previously announced $43 million private placement financing of common stock and warrants. As a part of the private placement, which closed in two tranches, the Company issued 9,555,556 shares of NxStage’s common stock at a price of $4.50 per share, and warrants to purchase 1,911,111 shares of its common stock at an exercise price of $5.50 per share, which price may be adjusted to $3.00 or $6.50 depending upon whether the Company achieves certain targets relating to the number of End Stage Renal Disease patients prescribed to receive therapy with the NxStage System One as of December 31, 2008. At the initial closing of the private placement on May 28, 2008, the Company issued 5,555,556 shares of common stock and 1,111,111 warrants to OrbiMed Advisors, LLC (OrbiMed) and received gross proceeds of $25 million. The second closing of the transaction was subject to the approval of NxStage stockholders, which was obtained at a Special Meeting of Stockholders held on July 31, 2008. At the second closing, the Company issued 4,000,000 shares of common stock and 800,000 warrants and received gross proceeds of $18 million.

NxStage will use proceeds of the private placement financing to advance further the commercialization of its products and the development of new products for its product pipeline. The Company also intends to use the proceeds for general corporate purposes.

About NxStage

NxStage Medical, Inc. (Nasdaq: NXTM) is a medical device company, headquartered in Lawrence, Massachusetts, USA, that develops, manufactures and markets innovative products for the treatment of ESRD and acute kidney failure. For more information on NxStage and its products, please visit the company’s website at www.nxstage.com.

Forward-Looking Statements

This release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this release that are not clearly historical in nature are forward-looking, and the words anticipate, believe, expect, estimate, plan, and similar expressions are generally intended to identify forward-looking statements. Examples of these forward-looking statements include statements as to the anticipated use of the private financing proceeds. All forward-looking statements involve risks, uncertainties and contingencies, many of which are beyond NxStage’s control, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance or achievements, including certain factors that may affect future operating results and which are detailed in NxStage’s filings with the Securities and Exchange Commission, including the Quarterly Report on Form 10- Q for the period ended March 31, 2008.

In addition, the statements in this press release represent NxStage’s expectations and beliefs as of the date of this press release. NxStage anticipates that subsequent events and developments may cause these expectations and beliefs to change. However, while NxStage may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so, whether as a result of new information, future events, or otherwise. These forward-looking statements should not be relied upon as representing NxStage’s expectations or beliefs as of any date subsequent to the date of this press release.

Kristen K. Sheppard, Esq.
VP, Investor Relations

SOURCE NxStage Medical, Inc.
Web site: http://www.nxstage.com