ImClone Systems Incorporated today announced that the first of its disease-directed clinical trials of the anti-vascular endothelial growth factor receptor-2 (VEGFR-2) monoclonal antibody IMC-1121B has opened for patient enrollment

NEW YORK, NY, USA | August 24, 2007| ImClone Systems Incorporated (NASDAQ: IMCL) today announced that the first of its disease-directed clinical trials of the anti-vascular endothelial growth factor receptor-2 (VEGFR-2) monoclonal antibody IMC-1121B has opened for patient enrollment.

This Phase II single-arm, multicenter study of IMC-1121B is enrolling patients with metastatic renal cell carcinoma whose disease has progressed during therapy with an approved VEGFR-2 tyrosine kinase inhibitor or who have developed intolerance to these agents. A total of 36 patients are expected to be enrolled. This Phase II study is designed to evaluate the efficacy, safety and pharmacology of IMC-1121B administered every two weeks by intravenous infusion.

"We are excited to have begun the Phase II study of IMC-1121B for advanced kidney cancer, as Phase I studies have shown this antibody’s ability to induce notable tumor responses as a single agent in various refractory tumor types, as well as having a favorable safety profile, all of which was predicted from our preclinical studies," said Eric K. Rowinsky, M.D., Chief Medical Officer and Senior Vice President of ImClone Systems. "This disease-directed study of IMC-1121B represents the first of a wide range of activity-finding studies, many of which will begin over the next several months in various rational tumor types."

IMC-1121B is a fully human IgG1 monoclonal antibody that is designed to bind to the VEGFR-2 found on tumor vasculature, thereby inhibiting certain ligands known as vascular endothelial growth factors from binding to and activating the receptor. This action blocks a signaling pathway key to new blood vessel formation in growing tumors, which has been shown to starve tumors of their nutrient supply and result in significant tumor growth inhibition in pre-clinical models.

About ImClone Systems

ImClone Systems Incorporated is a fully integrated biopharmaceutical company committed to advancing oncology care by developing and commercializing a portfolio of targeted biologic treatments designed to address the medical needs of patients with a variety of cancers. The Company’s research and development programs include growth factor blockers and angiogenesis inhibitors. ImClone Systems’ headquarters and research operations are located in New York City, with additional administration and manufacturing facilities in Branchburg, New Jersey. For more information about ImClone Systems, please visit the Company’s web site at http://www.imclone.com.

Certain matters discussed in this news release may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and the Federal securities laws. Although the company believes that the expectations reflected in such forward-looking statements are based upon reasonable assumptions, it can give no assurance that its expectations will be achieved. Forward-looking information is subject to certain risks, trends and uncertainties that could cause actual results to differ materially from those projected. Many of these factors are beyond the company’s ability to control or predict. Important factors that may cause actual results to differ materially and could impact the company and the statements contained in this news release can be found in the company’s filings with the Securities and Exchange Commission, including quarterly reports on Form 10-Q, current reports on Form 8-K and annual reports on Form 10-K. For forward-looking statements in this news release, the company claims the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. The company assumes no obligation to update or supplement any forward-looking statements whether as a result of new information, future events or otherwise.

SOURCE: IMCLONE SYSTEMS  INCORPORATED