ROCKVILLE, MD, April 1—EntreMed, Inc. (Nasdaq: ENMD), a clinical-stage pharmaceutical company developing therapeutics for the treatment of cancer and inflammatory diseases, today announced that Celgene Corporation (Nasdaq: CELG) has exercised warrants to purchase 7 million shares of EntreMed common stock for gross cash consideration of $10.5 million.

As a result of the transaction, the number of EntreMed common shares outstanding increased from 42,819,284 to 49,819,284 shares. The warrants, exercised at $1.50 a share, were part of a December 2002 transaction in which EntreMed licensed its thalidomide analog program to Celgene.

James S. Burns, EntreMed’s President and Chief Executive Officer, commented, “Financially, this transaction ensures that EntreMed has the resources necessary to fund operations into 2007.”

“More importantly, it provides funding in anticipation of moving our lead clinical candidate, Panzem® NCD, into Phase II clinical trials in the second half of 2005, and our second generation 2ME2 candidate, ENMD-1198, into Phase I clinical trials later this year,” Mr. Burns concluded.

As reflected in its recent 10-K filing, EntreMed’s cash and short-term investments were approximately $34.5 million at December 31, 2004. Coupled with certain inflows from contractual arrangements, and giving effect to Celgene’s current investment, EntreMed expects to have sufficient capital to fund planned operations into 2007.

For more information on EntreMed, visit the Company’s web site at http://www.entremed.com.

About EntreMed

EntreMed, Inc. (Nasdaq: ENMD) is a clinical-stage pharmaceutical company developing therapeutic candidates primarily for the treatment of cancer and inflammation. Panzem® (2-methoxyestradiol or 2ME2), the Company’s lead drug candidate, is currently in clinical trials for cancer, as well as in preclinical development for non-oncology indications. EntreMed’s goal is to develop and commercialize new compounds based on the Company’s expertise in angiogenesis, cell cycle regulation and inflammation—processes vital to the treatment of cancer and other diseases. Additional information about EntreMed is available on the Company’s website at http://www.entremed.com and in various filings with the Securities and Exchange Commission.

Forward Looking Statements

This release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act with respect to the outlook for expectations for future financial or business performance, strategies, expectations and goals. Forward-looking statements are subject to numerous assumptions, risks and uncertainties, which change over time. Forward-looking statements speak only as of the date they are made, and no duty to update forward-looking statements is assumed. Actual results could differ materially from those currently anticipated due to a number of factors, including those set forth in Securities and Exchange Commission filings under “Risk Factors,” including risks relating to the need for additional capital and the uncertainty of additional funding; the early-stage products under development; uncertainties relating to clinical trials; success in the clinical development of any products; dependence on third parties; future capital needs; and risks relating to the commercialization, if any, of the Company’s proposed products (such as marketing, safety, regulatory, patent, product liability, supply, competition and other risks).