ImClone Systems Incorporated (NASDAQ: IMCL), a global leader in the development and commercialization of novel antibodies to treat cancer, announced that it has enrolled the first patient in a disease-directed Phase II clinical trial of IMC-1121B to treat patients with advanced hepatocellular carcinoma (liver cancer). IMC-1121B, an anti-vascular endothelial growth factor receptor-2 (VEGFR-2) monoclonal antibody, is one of a number of proprietary antibodies in ImClone's robust clinical development pipeline.

This multicenter, multinational, open-label Phase II study of IMC-1121B is enrolling patients with advanced, inoperable liver cancer who have not received prior chemotherapy or other systemic therapies for their disease. A total of 40 patients are expected to be enrolled. The primary objective of the study is to determine the progression-free survival of patients with previously untreated and inoperable liver cancer when treated with IMC-1121B. This Phase II study is designed to evaluate the efficacy, safety and pharmacology of IMC-1121B administered every two weeks by intravenous infusion.

"Recently, targeting malignant angiogenesis has been shown to confer clinical benefit in patients with advanced liver cancer. IMC-1121B represents a potentially ideal therapeutic for treating patients with this cancer due to its high potency in blocking the VEGFR-2, the principal culprit that drives malignant angiogenesis," said Eric K. Rowinsky, M.D., Executive Vice President and Chief Medical Officer of ImClone. "Additionally, as a monoclonal antibody, IMC-1121B targets the VEGFR-2, thereby minimizing the likelihood of side effects that are noted with many new drugs, particularly the tyrosine kinase inhibitors that may affect many targets in a nonspecific manner."

"This Phase II trial is a part of a multipronged clinical development plan consisting of highly rational and strategically designed Phase II and III evaluations of IMC-1121B. We are rolling these out to serve as platforms for subsequent registrational activity, based on preclinical and early clinical results noted to date with ImClone's anti-VEGFR-2 antibodies," said John H. Johnson, Chief Executive Officer of ImClone.

IMC-1121B is a fully human IgG1 monoclonal antibody. It is designed to bind to a specific site on VEGFR-2, a receptor found on tumor vasculature, that results in blocking certain ligands known as vascular endothelial growth factors from binding to and activating the receptor. Anti-angiogenesis approaches, in particular blocking the activation of VEGF pathways, have been shown to be highly effective in treating cancer. IMC-1121B's unique mechanism of action specifically blocks VEGFR-2 activation, allowing for maximal angiogenesis inhibition. In 2007, ImClone conducted two Phase I studies of IMC-1121B, which demonstrated antitumor activity as a single agent and tolerable safety and pharmacologic profiles when administered either weekly or every two to three weeks. Enrollment in the weekly and every-two-weeks regimens is complete; however, patients continue to receive treatment with IMC-1121B. Enrollment in the every-three-week-regimen continues. In addition to the Phase II study of IMC-1121B in patients with advanced liver cancer, Phase II studies of IMC-1121B in patients with advanced kidney cancer and malignant melanoma have begun to enroll patients.

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 imclone.

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 currently expected. 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, particularly those factors identified as "risk factors" in the Company's most recent annual report of Form 10-K and in its quarterly reports on Form 10-Q and current reports on Form 8-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.

ImClone Systems