July 7, 2008

Phase 2 Study Of IMC-A12 for Advanced Soft Tissue Sarcoma Opens for Patient Enrollment

ImClone Systems Incorporated (NASDAQ: IMCL), a global leader in the development and commercialization of novel antibodies to treat cancer, today announced that a Phase 2 clinical trial of IMC-A12, ImClone's fully human, IgG1 anti-insulin-like growth factor-1 receptor (IGF-1R) monoclonal antibody, in adolescents and adult patients with several types of soft tissue sarcoma has opened for patient enrollment.

"This Phase 2 study of IMC-A12 builds on a biological rationale that suggests that the insulin-like growth factor receptor may confer a treatment advantage to these unique cancers versus conventional chemotherapy agents which often induce less than optimal results," said Eric K. Rowinsky, M.D., Chief Medical Officer and Executive Vice President of ImClone.

This multinational Phase 2 study will evaluate the efficacy of IMC-A12 in adult and adolescent (age greater than or equal to 12 years) patients with several types of previously treated, advanced or metastatic soft tissue sarcoma, which were selected based on the potential relevance of IGF-1R to tumor growth. Up to 185 patients are expected to be enrolled. Patients with the following types of soft-tissue sarcoma are eligible for study enrolment: Ewing's sarcoma, peripheral neuroectodermal tumor (PNET), rhabdomyosarcoma; leiomyosarcoma; adipocytic sarcoma, and synovial sarcoma. Based on supportive preclinical and biological rationale indicating that the IGF-1R and related signaling pathways may be overstimulated in these tumor types, and therefore particularly sensitive to IMC-A12, the primary objective of this Phase 2 study is to evaluate the efficacy of IMC-A12 in adults and adolescents with the aforementioned subtypes of soft tissue sarcoma. The study will also characterize the safety of IMC-A12 as a single agent administered on an every-two-week schedule.

"ImClone is making considerable progress in advancing the clinical development of IMC-A12 and the other novel antibodies in our proprietary pipeline," said John H. Johnson, Chief Executive Officer of ImClone. "This study in particular highlights ImClone's commitment to developing biologic therapies to treat all types of cancer in both adult and pediatric patients."

IMC-A12 is a fully human IgG1 monoclonal antibody. It is designed to specifically target the human IGF-1R, thereby inhibiting certain ligands known as IGFs 1 and 2 from binding to and activating the receptor. This action blocks a signaling pathway that enhances tumor cell proliferation and survival. In 2007, ImClone completed enrollment into two Phase 1 studies of IMC-A12, which demonstrated favorable safety and pharmacokinetic profiles, as well as preliminary evidence of antitumor activity as a single agent when administered either weekly or every two weeks. In addition to this Phase 2 study of IMC-A12 in adult and adolescent patients with soft tissue sarcoma, Phase 2 studies of IMC-A12 in patients with advanced prostate, pancreatic, colorectal, liver, and head and neck cancers, as well as a series of Phase 1/2 studies in pediatric malignancies and another evaluating the combination of IMC-A12 and temsirolimus, have begun to enroll patients.

About ImClone Systems

ImClone Systems Incorporated is a fully integrated global 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 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.