ROCKVILLE, MD., August 17, 2005—EntreMed, Inc. (Nasdaq: ENMD), a clinical-stage pharmaceutical company developing therapeutics for the treatment of cancer and inflammation, today announced the issuance of two U.S. patents covering its lead clinical-stage compound, 2-methoxyestradiol (2ME2) and multiple derivatives of 2ME2. 2ME2 (Panzem® Capsules and Panzem® NCD) is currently in clinical trials for cancer, as well as in preclinical development for inflammatory disorders.

The patents grant EntreMed intellectual property protection for 2ME2 and derivatives of 2ME2 in oncology and a broad range of non-oncology indications, including inflammatory disorders, immune disorders, cardiovascular disorders, and rheumatoid arthritis.

2ME2 is a novel anticancer agent, which is part of a next generation of antimitotic cancer drugs that bind to tubulin and work through multiple cellular pathways. 2ME2 can attack tumors on multiple fronts – directly by disrupting microtubules, an intracellular matrix necessary for the rapid division of cancer cells (mitosis), by inducing programmed cell death (apoptosis), and by blocking blood vessels that feed tumors (angiogenesis inhibition).

James S. Burns, EntreMed President & CEO, commented, “EntreMed is focused on the development of a new generation of small molecule drugs for the treatment of cancer and inflammatory disorders by attacking disease cells directly and the blood vessels that nourish them. These patents strengthen our position in next generation tubulin and angiogenesis inhibitors for the treatment of cancer and expand the range of indications for our lead anti-angiogenic agents.”

Mr. Burns further commented, “We have increasing evidence that 2ME2 has both antitumor and antiinflammatory properties. Recent preclinical studies have demonstrated the potential for 2ME2 as a disease modifying anti-rheumatic drug (DMARD) candidate. As a result, we have the potential to expand the clinical indications for 2ME2 into both oncology (Panzem® NCD) and rheumatoid arthritis. These patents cover both indications and a broad range of other 2ME2 anti-angiogenic indications. Our goal is to continue strengthening EntreMed’s intellectual property for its key product candidates, and to acquire additional technology and products that reinforce our focus on multi-mechanism drugs.”

U.S. Patent No. 6,930,128 entitled “Estrogenic Compounds as Anti-Mitotic Agents,” claims the use of 2-methoxyestradiol and derivatives of 2-methoxyestradiol for treatment of a wide variety of diseases that are angiogenesis mediated in a dosage sufficient to inhibit cell division and discloses novel compounds derived from 2-methoxyestradiol that inhibit microtubule formation, tubulin polymerization, and/or tubulin depolymerization.

Patent 6,930,128 further claims the use of 2-methoxyestradiol and derivatives of 2-methoxyestradiol for treating diseases or conditions selected from solid tumors, tumor metastasis, benign tumors, hemangiomas, atherosclerosis, abnormal wound healing, inflammatory disorders, immune disorders, rheumatoid arthritis, ocular neovascularization, macular degeneration and gynecological disorders with compounds having certain structural modifications of 2-methoxyestradiol.

U.S. Patent No. 6,908,910 entitled “Estrogenic Compounds as Anti-Mitotic Agents,” which issued in June 2005, represents a further enhancement of patent claims to the use of 2-methoxyestradiol for treatment of a wide variety of ophthalmic diseases that are angiogenesis mediated. The patent claims methods for treating diseases or conditions with compounds having certain structural modifications of 2-methoxyestradiol. Both patents are owned by Children’s Hospital Boston and licensed exclusively to EntreMed.

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, such as rheumatoid arthritis. Additional information about EntreMed is available on the Company’s website at 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).