8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 3, 2006

IMCLONE SYSTEMS INCORPORATED

(Exact name of registrant as specified in its charter)

Delaware	0-19612	04-2834797
(State or other jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)

180 Varick Street

New York, New York 10014

(Address of principal executive offices) (Zip Code)

(212) 645-1405

(Registrant’s telephone number, including area code)

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

oWritten communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

oSoliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

oPre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

oPre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

ITEM 8.01. Other Events.

The text of certain press releases issued by ImClone Systems Incorporated (the “Company”) in connection with the American Society of Clinical Oncology (“ASCO”) 42nd Annual Meeting, attached hereto as Exhibits 99.1, 99.2, 99.3 and 99.4, is incorporated by reference herein in its entirety.

Please note that under Abstract #3551 in the press release attached hereto as Exhibit 99.4 (the “Press Release”), the trial’s abstract information on nine week response and disease control rates is incorrectly disclosed as the trial’s poster information. Accordingly, the fourth and fifth sentences of the Press Release’s discussion under Abstract #3551, with respect to the trial’s poster information, should read as follows:  “At nine weeks, response rates were 27% (10/37) in the chemotherapy alone arm and 57% (21/37) in the combination ERBITUX and chemotherapy arm. At nine weeks, rates of disease control were 84% (31/37) in the chemotherapy alone arm and 86% (32/37) in the combination ERBITUX and chemotherapy arm.”  In addition, at 18 weeks, disease control rates were 46% (17/37) and 65% (24/37), respectively, and response rates were 30% (11/37) and 51% (19/37), respectively.

In addition, please note that under Abstract #3550 in the Press Release, which discloses a 68% response rate in the ERBITUX, capecitabine and oxaliplatin (“CCO”) arm of the subject Phase II trial,  the number of patients in the relevant denominator is incorrectly disclosed. As reported in the poster presentation, the 68% response rate was by reference to 17/25 patients and not 17/51 patients.

ITEM 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.	Description
99.1	Company press release dated June 3, 2006.
99.2	Company press release dated June 4, 2006.
99.3	Company press release dated June 4, 2006.
99.4	Company press release dated June 5, 2006.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

		IMCLONE SYSTEMS INCORPORATED
		(Registrant)
Dated: June 8, 2006	By:	/s/ Erik D. Ramanathan
		Erik D. Ramanathan
		Senior Vice President, Secretary and General Counsel

EX-99.1

Exhibit 99.1

ImClone Systems Incorporated
	180 Varick Street New York, NY 10014 Tel: (212) 645-1405 Fax: (212) 645-2054 www.imclone.com

ImClone Systems Incorporated
Investors:	Media:
Andrea F. Rabney	David M. F. Pitts
(646) 638-5058	(646) 638-5058
Stefania Bethlen
(646) 638-5058

Abstracts  3032 and 3024

Embargoed by ASCO until 8:00 AM EDT, June 3, 2006

IMCLONE SYSTEMS PRESENTS PROMISING PHASE I DATA ON TWO PIPELINE
ANTIBODIES AT ASCO ANNUAL MEETING

Atlanta, GA — June 3, 2006 — ImClone Systems Incorporated (NASDAQ: IMCL) today announced promising Phase I data on two of the Company’s fully-human, IgG1 monoclonal antibodies, IMC-1121B and IMC-11F8, at the American Society of Clinical Oncology 42nd Annual Meeting in Atlanta, GA.

The first of these antibodies, IMC-1121B, aims to inhibit the function of a signaling pathway known to play a role in the formation of blood vessels in tumors — a process known as angiogenesis — by blocking the vascular endothelial growth factor receptor-2 (VEGFR-2) from binding to molecules (ligands) that stimulate its activation.

A Phase I study was designed to characterize the principal toxicities, dose-limiting toxicity and maximum tolerated dose of IMC-1121B, as well as assess any preliminary evidence of antitumor activity. To date, a total of 14 patients with advanced cancer have been enrolled in the study at varying dose levels. The most frequent adverse events were anorexia, vomiting, anemia, depression, fatigue and insomnia. Preliminary results of the study suggest that the toxicity profile of IMC-1121B is distinct from other VEGF pathway inhibitors and that its pharmacokinetic profile is similar to other growth factor receptor pathway antibodies. Further, promising early evidence of antitumor activity was observed, where one patient experienced a partial response and five patients had stable disease. Dose escalation continues and imaging and biological endpoints are in process.

The second antibody, IMC-11F8, is a high affinity antibody that blocks ligand-dependent activation of the epidermal growth factor receptor (EGFR). EGFR is part of a signaling pathway that is linked to the growth, development and survival of many human cancer cells. Studies have shown that the inhibition of EGFR with an IgG1 antibody blocks phosphorylation, resulting in the inhibition of cell growth, the induction of cell death, a decreased ability to form tumor vasculature and the recruitment of the body’s immune defenses to attack cancer cells.

A Phase I study is being conducted to determine the safety profile and recommended dose of IMC-11F8. To date, 31 out of 40 planned patients with advanced solid tumors who are refractory to, or have no

available, standard therapy have been enrolled at various dose levels. The most frequent adverse events were nausea, vomiting, fatigue and headache. No infusion reactions were observed. Although a maximum tolerated dose has not been established, IMC-11F8 has shown activity at two different dose levels.

“These antibodies are among several targeted therapies in development at ImClone Systems that give us a uniquely valuable pipeline within the industry,” stated Eric K. Rowinsky, M.D., Chief Medical Officer of ImClone Systems. “We are very excited about the anti-tumor activity demonstrated by both of these compounds at this early stage of testing. Because the proof of principle for both of these antibodies has been well established by commercially available therapies, we are optimistic that Phase III testing can begin shortly after Phase I is complete.”

The exclusive rights to market IMC-11F8 outside the United States and Canada and co-exclusive development rights in Japan belong to ImClone Systems, while commercial rights to the antibody in the U.S., Canada and Japan fall within the scope of ImClone Systems’ commercial agreement with Bristol-Myers Squibb regarding ERBITUX®. Commercial rights to IMC-1121B have not been partnered.

About ImClone Systems Incorporated

ImClone Systems Incorporated is 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’ strategy is to become a fully integrated biopharmaceutical company, taking its development programs from the research stage to the market. ImClone Systems’ headquarters and research operations are located in New York City, with additional administration and manufacturing facilities in Branchburg, New Jersey.

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.

#  #  #

2

EX-99.2

Exhibit 99.2

ImClone Systems Incorporated
	180 Varick Street New York, NY 10014 Tel: (212) 645-1405 Fax: (212) 645-2054 www.imclone.com

ImClone Systems Incorporated
Investors:	Media:
Andrea F. Rabney	David M. F. Pitts
(646) 638-5058	(646) 638-5058
Stefania Bethlen

(646) 638-5058

EFFICACY RESULTS FROM A RANDOMIZED PHASE II STUDY OF PATIENTS WITH
ADVANCED LUNG CANCER SUPPORT CONTINUED STUDY OF CONCURRENT
CHEMOTHERAPY PLUS ERBITUX® (CETUXIMAB)

Atlanta, GA—June 4, 2006—ImClone Systems Incorporated (NASDAQ: IMCL) today announced findings from a Southwest Oncology Group randomized clinical trial (SWOG-0342) of ERBITUX®(Cetuximab), an IgG1 monoclonal antibody, in non-small cell lung cancer. The large, randomized Phase II trial was designed to select an ERBITUX—chemotherapy regimen for future evaluation and subsequent inclusion in a Phase III trial. This study was presented today in an oral session at the American Society of Clinical Oncology (ASCO) 42nd Annual Meeting by Karen Kelly, M.D., Clinical Director of the Thoracic Oncology Program, University of Colorado Cancer Center.

A total of 225 untreated patients with advanced stage non-small cell lung cancer (NSCLC), both squamous and non-squamous cell, were enrolled in the study and randomized to receive either chemotherapy (paclitaxel plus carboplatin) plus ERBITUX (n=106) or the same doses of chemotherapy followed by ERBITUX (n=119). The primary endpoint of the study was overall survival. The regimen that produced a median survival of at least 10 months would be declared a candidate for further evaluation. Median survival was 10 months in the concurrent ERBITUX treatment arm and 9 months in the consecutive ERBITUX treatment arm. The concurrent regimen of chemotherapy and ERBITUX met the study’s criteria for continued evaluation. Secondary endpoints included response rate, which were 37% and 25% in the concurrent and consecutive treatment arms, respectively, and median progression free survival, which was the same in both treatment groups at 4 months. Response rate to concurrent chemotherapy and ERBITUX is among the highest observed in this treatment setting in a multicenter cooperative group study.

Investigators concluded that no significant differences in efficacy or toxicity were observed between the treatment arms. The serious adverse events (Grade 3/4) observed in the concurrent ERBITUX treatment arm and in the consecutive ERBITUX treatment arm were neutropenia (41%/37%), rash (12%, 5%), febrile neutropenia (4%, 2%), and allergic reaction (5%, 0%) respectively.

ERBITUX’s role in the treatment of NSCLC in combination with chemotherapy, other biologics and with radiation is currently under evaluation in different disease settings. The NCI-sponsored research groups

involved, in addition to SWOG, include the Radiation Treatment Oncology Group (RTOG), Cancer and Leukemia Group B (CALGB) and Eastern Cooperative Oncology Group (ECOG).

About ERBITUX® (Cetuximab)

ERBITUX is an IgG1 monoclonal antibody (IgG1 MAb) designed to inhibit the function of a molecular structure expressed on the surface of normal and tumor cells called the epidermal growth factor receptor (EGFR, HER1, c-ErbB-1). EGFR is part of a signaling pathway that is linked to the growth, development, and survival of many human cancer cells.  In vitro assays and in vivo animal studies have shown that binding of ERBITUX to the EGFR blocks phosphorylation, resulting in multiple EGFR-mediated anti-tumor effects. Additionally, as an IgG1 MAb, ERBITUX has been shown in vitro to mediate the recruitment of the body’s immune system defenses to attack cancer cells (antibody-dependent cell-mediated cytotoxicity) in certain human tumor types. While the specific mechanism of ERBITUX’ anti-tumor effect(s) in vivo is unknown, the combination of these processes may contribute to the overall therapeutic effect of ERBITUX.

ERBITUX (Cetuximab), in combination with radiation therapy, is indicated for the treatment of locally or regionally advanced squamous cell carcinoma of the head and neck. ERBITUX as a single agent is indicated for the treatment of patients with recurrent or metastatic squamous cell carcinoma of the head and neck for whom prior platinum-based therapy has failed.

ERBITUX is indicated for the treatment of EGFR-expressing, metastatic colorectal carcinoma in combination with irinotecan for patients who are refractory to irinotecan-based chemotherapy, and as a single agent for patients who are intolerant to irinotecan-based therapy. The effectiveness of ERBITUX in EGFR-expressing mCRC cancer is based on objective response rates. Currently, no data are available in mCRC that demonstrate an improvement in disease-related symptoms or increased survival with ERBITUX.

For full prescribing information, including boxed WARNINGS regarding infusion reactions and cardiopulmonary arrest, visit http://www.ERBITUX.com.

Important Safety Information  

Grade 3/4 infusion reactions, rarely with fatal outcome (<1 in 1000), occurred in approximately 3% (46/1485) of patients receiving ERBITUX (Cetuximab) therapy, characterized by rapid onset of airway obstruction (bronchospasm, stridor, hoarseness), urticaria, hypotension, and/or cardiac arrest. Severe infusion reactions require immediate and permanent discontinuation of ERBITUX therapy.

Most reactions (90%) were associated with the first infusion of ERBITUX despite the use of prophylactic antihistamines. Caution must be exercised with every ERBITUX infusion as there were patients who experienced their first severe infusion reaction during later infusions. A 1-hour observation period is recommended following the ERBITUX infusion. Longer observation periods may be required in patients who experience infusion reactions.

Cardiopulmonary arrest and/or sudden death occurred in 2% (4/208) of patients with squamous cell carcinoma of the head and neck treated with radiation therapy and ERBITUX as compared to none of 212 patients treated with radiotherapy alone. Fatal events occurred within 1 to 43 days after the last ERBITUX treatment. ERBITUX in combination with radiation therapy should be used with caution in patients with known coronary artery disease, congestive heart failure and arrhythmias. Close monitoring of serum electrolytes, including serum magnesium, potassium, and calcium during and after Cetuximab therapy is recommended.

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Severe cases of interstitial lung disease (ILD), which was fatal in one case, occurred in less than 0.5% of 774 patients with advanced colorectal cancer (mCRC) receiving ERBITUX. There was one case (n=796) of ILD reported in patients with in head and neck cancer receiving ERBITUX in clinical studies.

In clinical studies of ERBITUX, dermatologic toxicities, including acneform rash, skin drying and fissuring, and inflammatory and infectious sequelae (eg, blepharitis, cheilitis, cellulitis, cyst) were reported. In 208 patients receiving ERBITUX + RT, acneform rash was reported in 87% (17% severe) as compared to 10% in 212 patients treated with radiation therapy alone (1% severe). In patients receiving ERBITUX alone, 76% (N=103) experienced acneform rash (1% severe). Severe (Grade 3/4) acneform rash was reported in 11% of 774 patients with metastatic colorectal cancer treated with ERBITUX. Sun exposure may exacerbate these effects. A related nail disorder, occurring in 12% (0.4% Grade 3) of patients, was characterized as a paronychial inflammation.

The safety of ERBITUX in combination with radiation therapy and cisplatin has not been established. Death and serious cardiotoxicity were observed in a single-am trial with ERBITUX, delayed, accelerated (concomitant boost) fractionation radiation therapy, and cisplatin (100 mg/m2) conducted in patients with locally advanced squamous cell carcinoma of the head and neck. Two of 21 patients died, one as a result of pneumonia and one of an unknown cause. Four patients discontinued treatment due to adverse events. Two of these discontinuations were due to cardiac events (myocardial infarction in one patient and arrhythmia, diminished cardiac output, and hypotension in the other patient).

The incidence of hypomagnesemia (both overall and severe [NCI CTC Grades 3 & 4]) was increased in patients receiving ERBITUX alone or in combination with chemotherapy as compared to those receiving best supportive care or chemotherapy alone based on ongoing, controlled clinical trials in 244 patients. Approximately one-half of these patients receiving ERBITUX experienced hypomagnesemia and 10-15% experienced severe hypomagnesemia. Electrolyte repletion was necessary in some patients and in severe cases, intravenous replacement was required. Patients receiving ERBITUX therapy should be periodically monitored for hypomagnesemia, and accompanying hypocalcemia and hypokalemia during, and up to 8 weeks following the completion of, ERBITUX therapy

The most serious adverse reactions associated with ERBITUX in combination with radiation therapy in 208 patients with head and neck cancer were infusion reaction (3%), cardiopulmonary arrest (2%), dermatologic toxicity (2.5%), mucositis (6%), radiation dermatitis (3%), confusion (2%), and diarrhea (2%).

The most serious adverse reactions associated with ERBITUX in mCRC clinical trials (N=774) were infusion reaction (3%), dermatologic toxicity (1%), interstitial lung disease (0.4%), fever (5%), sepsis (3%), kidney failure (2%), pulmonary embolus (1%), dehydration (5% in patients receiving ERBITUX with irinotecan, 2% in patients receiving ERBITUX as a single agent) and diarrhea (6% in patients receiving ERBITUX with irinotecan, 0.2% in patients receiving ERBITUX as a single agent).

The overall incidence of late radiation toxicities (any grade) was higher with ERBITUX in combination with radiation therapy compared with radiation therapy alone. The following sites were affected: salivary glands (65%/56%), larynx (52%/36%), subcutaneous tissue (49%/45%), mucous membranes (48%/39%), esophagus (44%/35%), skin (42%/33%), brain (11%/9%), lung (11%/8%), spinal cord (4%/3%), and bone (4%/5%) in the ERBITUX and radiation versus radiation alone arms, respectively.

The incidence of Grade 3 or 4 late radiation toxicities were generally similar between the radiation therapy alone and the ERBITUX plus radiation therapy arms.

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The most common adverse events seen in patients with carcinomas of the head and neck receiving ERBITUX in combination with radiation therapy (n=208) versus radiation alone (n=212) were mucositis-stomatitis (93%/94%), acneform rash (87%/10%), radiation dermatitis (86%/90%), weight loss (84%/72%), xerostomia (72%/71%), dysphagia (65%/63%), asthenia (56%/49%), nausea (49%/37%), constipation (35%/30%) and vomiting (29%/23%). The most common adverse events seen in patients receiving ERBITUX as a single agent (N=103) were acneform rash (76%), asthenia (45%), pain (28%), fever (27%) and weight loss (27%). The most common adverse events seen in patients receiving ERBITUX with irinotecan (n=354) or ERBITUX as a single agent (n=420) were acneform rash (88%/90%), asthenia/malaise (73%/48%), diarrhea (72%/25%), nausea (55%/29%), abdominal pain (45%/26%), vomiting (41%/25%), fever (34%/27%), constipation (30%/26%), and headache (14%/26%).

About Lung Cancer

According to the American Cancer Society, nearly 175,000 Americans will be diagnosed with lung cancer this year, accounting for 12% of cancer diagnoses. Additionally, more than 160,000 will die from lung cancer in 2006, and the disease is the most common cancer-related death in men and women. There are two types of lung cancer, non-small cell and small-cell lung cancer. Approximately 87% of all lung cancers are the non-small cell type.(1)

About ImClone Systems

ImClone Systems Incorporated is committed to advancing oncology care by developing 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’ strategy is to become a fully integrated biopharmaceutical company, taking its development programs from the research stage to the market. ImClone Systems’ headquarters and research operations are located in New York City, with additional administration and manufacturing facilities in Branchburg, New Jersey.

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.

#   #   #

(1)American Cancer Society: Cancer Facts and Figures 2006. http://www.cancer.org/downloads/STT/CAFF2006PWSecured.pdf. Accessed 5/16/06.

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EX-99.3

Exhibit 99.3

ImClone Systems Incorporated
	180 Varick Street New York, NY 10014 Tel: (212) 645-1405 Fax: (212) 645-2054 www.imclone.com

ImClone Systems Incorporated
Investors:	Media:
Andrea F. Rabney	David M. F. Pitts
(646) 638-5058	(646) 638-5058
Stefania Bethlen
(646) 638-5058

CLINICAL DATA SUGGEST ERBITUX® RECRUITS THE BODY’S IMMUNE SYSTEM TO
HELP FIGHT CANCER AND MAY BE ADMINISTERED BIWEEKLY

Data Presented at American Society of Clinical Oncology 42nd Annual Meeting

Atlanta, GA—June 4, 2006—ImClone Systems Incorporated (NASDAQ: IMCL) today announced data from two clinical trials of ERBITUX® (Cetuximab), the first of which examined ERBITUX activation of antibody-dependent cell-mediated cytotoxicity (ADCC), and the second of which explored ERBITUX administration on an every two week schedule. Combined, these features serve to distinguish ERBITUX from competing EGFR-targeted therapies. The studies were presented at the American Society of Clinical Oncology (ASCO) 42nd Annual Meeting in Atlanta, GA.

Abstract 3028

Wu Zhang, M.D., of the University of Southern California Norris Comprehensive Cancer Center in Los Angeles, presented findings in a poster discussion session from a clinical study conducted at the USC Norris Comprehensive Cancer Center that suggest ERBITUX plays a role in recruitment of the body’s immune systems to attack and kill cancer cells, a function known as ADCC.

Recent studies have shown that ADCC, mediated through certain receptors on the surface of many of the body’s immune system cells such as white blood cells and natural killer cells, can be activated by the use of IgG1 monoclonal antibodies. This activity provides an important additional anti-tumor effect which can contribute to the overall efficacy of IgG1 antibodies as compared to other IgG subclasses.(1)

Because it is an IgG1 antibody, ERBITUX has two regions with the ability to bind to two different kinds of cell surface receptors. One region, known as the fragment binding antigen or Fab region, is designed to inhibit the function of a molecular structure called the epidermal growth factor receptor (EGFR), which is found on normal cells and tumor cells. The other region, known as the fragment crystallizable or Fc region, has demonstrated, in vitro, the ability to bind to immune cells that can play a role in killing tumor cells.

Based on evidence from a clinical study of the chimeric IgG1 antibody rituximab,(2) an antibody in the same subclass as ERBITUX, investigators from the USC Norris Comprehensive Cancer Center sought to determine whether response to the use of ERBITUX as a single agent could be predicted based on the type and presence of certain receptors known to regulate ADCC. Thirty-nine patients with EGFR-expressing metastatic colorectal cancer who failed treatment with at least two prior chemotherapies were enrolled in the study. A blood sample was collected from each patient at the beginning of treatment and genomic DNA was extracted from white blood cells contained in the sample.

Two receptors found to predict ADCC activation and improved outcome to rituximab,(2,3) known as FcyRIIIa158V/F andFcyRIIa 131 H/R, were also found to be potential molecular markers for ADCC activation and improved clinical outcome of patients treated with single agent ERBITUX. The study found that patients whose white blood cells expressed these receptors had a median survival of 10.7 months versus 2.3 months for those without (p=0.093). In addition, 86% of patients (19/22) with the receptors saw their tumors shrink or remain stable while only 18% of patients (2/11) without this receptor had similar responses (p<0.001). Progression free survival for those with the receptors was 3.7 months versus 1.1 months for those without (p=0.004). Investigators concluded that these data demonstrated for the first time that ADCC contributes to overall therapeutic effect of ERBITUX.

“A growing body of evidence exists supporting the relationship between IgG1 antibodies directed at cancer cells and the activation of the body’s immune system against those cells,” stated Dr. Heinz-Josef Lenz, M.D., senior author of the study and Professor of Medicine in the Keck School of Medicine, Scientific Director, Cancer Genetics Unit and Associate Director, Gastrointestinal Oncology Program at the USC Norris Comprehensive Cancer Center. “It will be important to conduct further studies to strengthen this correlation for ERBITUX and to test it across a variety of tumor types where ERBITUX is used.”

Abstract 3085

Because ERBITUX has a long terminal half-life and is frequently given in combination with biweekly chemotherapy, investigators sought to compare the safety, pharmacokinetics (how a drug is absorbed, distributed, metabolized and eliminated by the body) and pharmacodynamics (effects of drugs on tissue and organs in the body) of a biweekly ERBITUX infusion schedule with the currently approved weekly schedule in a Phase I study.

In a poster session, Josep Tabernero, M.D., of the Vall d’Hebron University Hospital in Barcelona, Spain and Principal Investigator of the study, presented findings from nine patients who were given weekly ERBITUX at its labeled dose and 20 patients who were given biweekly ERBITUX, 10 each at a 400 mg/m2 dose and a 500 mg/m2 dose. Pharmacokinetic data between the weekly and biweekly regimens were predictable (Cmin, AUC) and comparable (t1/2, CLss) and preliminary skin pharmacodynamic studies showed no major difference in the EGFR-signaling inhibition between regimens.

Investigators concluded that preliminary study data showed no major difference in pharmacokinetic and pharmacodynamic profiles with the weekly and biweekly schedules. Examination of higher dose levels at the biweekly schedule is ongoing.

References:

1. Iannello, A. and Ahmad, A. Role of antibody-dependent cell-mediated cytotoxicity in the efficacy of therapeutic anti-cancer monoclonal antibodies. Cancer Metastasis Rev 2005; 24: 487-499,

2. Wu, J., Edberg, J. C., Redecha, P. B., Bansal, V., Guyre, P. M., Coleman, K., Salmon, J. E., and Kimberly, R. P. A novel polymorphism of FcgammaRIIIa (CD16) alters receptor function and predisposes to autoimmune disease. J Clin Invest 1997; 100: 1059-1070,

3. Jiang, X. M., Arepally, G., Poncz, M., and McKenzie, S. E. Rapid detection of the Fc gamma RIIA-H/R 131 ligand-binding polymorphism using an allele-specific restriction enzyme digestion (ASRED). J Immunol Methods 1996; 199: 55-59,

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About ERBITUX® (Cetuximab)

ERBITUX is an IgG1 monoclonal antibody (IgG1 MAb) designed to inhibit the function of a molecular structure expressed on the surface of normal and tumor cells called the epidermal growth factor receptor (EGFR, HER1, c-ErbB-1). EGFR is part of a signaling pathway that is linked to the growth, development, and survival of many human cancer cells.  In vitro assays and in vivo animal studies have shown that binding of ERBITUX to the EGFR blocks phosphorylation, resulting in multiple EGFR mediated anti-tumor effects. Additionally, as an IgG1 MAb, ERBITUX has shown in vitro to mediate the recruitment of the body’s immune system defenses to attack cancer cells (antibody-dependent cell-mediated cytotoxicity) in certain human tumor types. While the specific mechanism of ERBITUX’ anti-tumor effect(s) in vivo is unknown, the combination of these processes may contribute to the overall therapeutic effect of ERBITUX.

ERBITUX (Cetuximab), in combination with radiation therapy, is indicated for the treatment of locally or regionally advanced squamous cell carcinoma of the head and neck. ERBITUX as a single agent is indicated for the treatment of patients with recurrent or metastatic squamous cell carcinoma of the head and neck for whom prior platinum-based therapy has failed.

ERBITUX is indicated for the treatment of EGFR-expressing, metastatic colorectal carcinoma in combination with irinotecan for patients who are refractory to irinotecan-based chemotherapy, and as a single agent for patients who are intolerant to irinotecan-based therapy. The effectiveness of ERBITUX in EGFR-expressing mCRC cancer is based on objective response rates. Currently, no data are available in mCRC that demonstrate an improvement in disease-related symptoms or increased survival with ERBITUX.

For full prescribing information, including boxed WARNINGS regarding infusion reactions and cardiopulmonary arrest, visit http://www.ERBITUX.com.

Important Safety Information  

Grade 3/4 infusion reactions, rarely with fatal outcome (<1 in 1000), occurred in approximately 3% (46/1485) of patients receiving ERBITUX (Cetuximab) therapy, characterized by rapid onset of airway obstruction (bronchospasm, stridor, hoarseness), urticaria, hypotension, and/or cardiac arrest. Severe infusion reactions require immediate and permanent discontinuation of ERBITUX therapy.

Most reactions (90%) were associated with the first infusion of ERBITUX despite the use of prophylactic antihistamines. Caution must be exercised with every ERBITUX infusion as there were patients who experienced their first severe infusion reaction during later infusions. A 1-hour observation period is recommended following the ERBITUX infusion. Longer observation periods may be required in patients who experience infusion reactions.

Cardiopulmonary arrest and/or sudden death occurred in 2% (4/208) of patients with squamous cell carcinoma of the head and neck treated with radiation therapy and ERBITUX as compared to none of 212 patients treated with radiation therapy alone. ERBITUX in combination with radiation therapy should be used with caution in patients with known coronary artery disease, congestive heart failure and arrhythmias.

3

Close monitoring of serum electrolytes, including serum magnesium, potassium, and calcium during and after ERBITUX therapy is recommended.

Severe cases of interstitial lung disease (ILD), which was fatal in one case, occurred in less than 0.5% of 774 patients with advanced colorectal cancer (mCRC) receiving ERBITUX. There was one case of ILD reported in 796 patients with head and neck cancer receiving ERBITUX in clinical studies.

In clinical studies of ERBITUX, dermatologic toxicities, including acneform rash, skin drying and fissuring, and inflammatory and infectious sequelae (eg, blepharitis, cheilitis, cellulitis, cyst) were reported. In 208 patients receiving ERBITUX + RT, acneform rash was reported in 87% (17% severe) as compared to 10% in 212 patients treated with radiation therapy alone (1% severe). In patients receiving ERBITUX alone, 76% (N=103) experienced acneform rash (1% severe). Severe (Grade 3/4) acneform rash was reported in 11% of 774 patients with metastatic colorectal cancer treated with ERBITUX. Sun exposure may exacerbate these effects. A related nail disorder, occurring in 12% (0.4% Grade 3) of patients, was characterized as a paronychial inflammation.

The safety of ERBITUX in combination with radiation therapy and cisplatin has not been established. Death and serious cardiotoxicity were observed in a single-am trial with ERBITUX, delayed, accelerated (concomitant boost) fractionation radiation therapy, and cisplatin (100 mg/m2) conducted in patients with locally advanced squamous cell carcinoma of the head and neck. Two of 21 patients died, one as a result of pneumonia and one of an unknown cause. Four patients discontinued treatment due to adverse events. Two of these discontinuations were due to cardiac events (myocardial infarction in one patient and arrhythmia, diminished cardiac output, and hypotension in the other patient).

The incidence of hypomagnesemia (both overall and severe [NCI CTC Grades 3 & 4]) was increased in patients receiving ERBITUX alone or in combination with chemotherapy as compared to those receiving best supportive care or chemotherapy alone based on ongoing, controlled clinical trials in 244 patients. Approximately one-half of these patients receiving ERBITUX experienced hypomagnesemia and 10-15% experienced severe hypomagnesemia. Electrolyte repletion was necessary in some patients and in severe cases, intravenous replacement was required. Patients receiving ERBITUX therapy should be periodically monitored for hypomagnesemia, and accompanying hypocalcemia and hypokalemia during, and up to 8 weeks following the completion of, ERBITUX therapy.

The most serious adverse reactions associated with ERBITUX in combination with radiation therapy in 208 patients with head and neck cancer were infusion reaction (3%), cardiopulmonary arrest (2%), dermatologic toxicity (2.5%), mucositis (6%), radiation dermatitis (3%), confusion (2%), and diarrhea (2%).

The most serious adverse reactions associated with ERBITUX in mCRC clinical trials (N=774) were infusion reaction (3%), dermatologic toxicity (1%), interstitial lung disease (0.4%), fever (5%), sepsis (3%), kidney failure (2%), pulmonary embolus (1%), dehydration (5% in patients receiving ERBITUX with irinotecan, 2% in patients receiving ERBITUX as a single agent) and diarrhea (6% in patients receiving ERBITUX with irinotecan, 0.2% in patients receiving ERBITUX as a single agent).

The overall incidence of late radiation toxicities (any grade) was higher with ERBITUX in combination with radiation therapy compared with radiation therapy alone. The following sites were affected: salivary glands (65%/56%), larynx (52%/36%), subcutaneous tissue (49%/45%), mucous membranes (48%/39%), esophagus (44%/35%), skin (42%/33%), brain (11%/9%), lung (11%/8%), spinal cord (4%/3%), and bone (4%/5%) in the ERBITUX and radiation versus radiation alone arms, respectively.

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The incidence of Grade 3 or 4 late radiation toxicities were generally similar between the radiation therapy alone and the ERBITUX plus radiation therapy arms.

The most common adverse events seen in patients with carcinomas of the head and neck receiving ERBITUX in combination with radiation therapy (n=208) versus radiation alone (n=212) were mucositis-stomatitis (93%/94%), acneform rash (87%/10%), radiation dermatitis (86%/90%), weight loss (84%/72%), xerostomia (72%/71%), dysphagia (65%/63%), asthenia (56%/49%), nausea (49%/37%), constipation (35%/30%) and vomiting (29%/23%). The most common adverse events seen in patients receiving ERBITUX as a single agent (N=103) were acneform rash (76%), asthenia (45%), pain (28%), fever (27%) and weight loss (27%).

The most common adverse events seen in patients receiving ERBITUX with irinotecan (n=354) or ERBITUX as a single agent (n=420) were acneform rash (88%/90%), asthenia/malaise (73%/48%), diarrhea (72%/25%), nausea (55%/29%), abdominal pain (45%/26%), vomiting (41%/25%), fever (34%/27%), constipation (30%/26%), and headache (14%/26%).

About Colorectal Cancer

In the U.S., approximately 149,000 people will be diagnosed with cancer of the colon or rectum this year. Half of these patients have metastatic disease, or cancer that has spread to other organs, at the time of diagnosis. EGFR is expressed in up to 77.7 % of colorectal cancer tumors. Colorectal cancer is the third most common cancer in both men and women.(i)

About ImClone Systems Incorporated

ImClone Systems Incorporated is 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’ strategy is to become a fully integrated biopharmaceutical company, taking its development programs from the research stage to the market. ImClone Systems’ headquarters and research operations are located in New York City, with additional administration and manufacturing facilities in Branchburg, New Jersey.

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.

#  #  #

(i)American Cancer Society: Cancer Facts and Figures 2006. http://www.cancer.org/downloads/STT/CAFF2006PWSecured.pdf. Accessed 5/16/06.

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EX-99.4

Exhibit 99.4

ImClone Systems Incorporated
	180 Varick Street New York, NY 10014 Tel: (212) 645-1405 Fax: (212) 645-2054 www.imclone.com

ImClone Systems Incorporated
Investors:	Media:
Andrea F. Rabney	David M. F. Pitts
(646) 638-5058	(646) 638-5058
Stefania Bethlen
(646) 638-5058

Abstract 3509, 3550, 3551, 3557 and 3559

SCIENTIFIC DATA PRESENTED AT ASCO ANNUAL MEETING EVALUATING
ERBITUX®(CETUXIMAB) IN COMBINATION WITH CHEMOTHERAPY AS FIRST
LINE TREATMENT OF ADVANCED COLORECTAL CANCER

Atlanta, GA — June 5, 2006 — ImClone Systems Incorporated (NASDAQ: IMCL) today announced that data from five clinical trials for the investigational use of ERBITUX® (Cetuximab) as first line treatment of metastatic colorectal cancer in combination with various chemotherapies were presented here at the American Society of Clinical Oncology (ASCO) 42nd Annual Meeting in Atlanta, GA.

Investigators who conducted the studies presented the following data:

Abstract #3509

In an oral session, Allen Venook, M.D., Professor, Clinical Medicine, University of California, San Francisco, presented results from a Cancer and Leukemia Group B randomized clinical trial (CALGB-80203) of ERBITUX in the treatment of patients with previously untreated metastatic colorectal cancer. A total of 238 patients with untreated metastatic adenocarcinoma of the colon or rectum were enrolled in the study and received either chemotherapy (randomized between FOLFIRI or FOLFOX) or chemotherapy plus ERBITUX. The median follow-up for all patients was 16 months. The study was originally designed to enroll 2,200 patients and powered to determine whether ERBITUX conferred a survival benefit when added to chemotherapy. Enrollment was closed at 238 patients (representing only 11% of the intended power) to account for an evolving standard of care in the first line treatment of metastatic colorectal cancer, including the emergence of oxliplatin and bevacizumab as therapies in this setting.

The primary endpoint of the study was overall survival and secondary endpoints were response rate, progression free survival and toxicity. Response rate among patients treated with the combination of ERBITUX and chemotherapy was 52% (61/117) versus a response rate of 38% (46/121) (p = 0.029) for patients treated with chemotherapy alone. As the study was closed prematurely, the survival and progression free survival endpoints were not sufficiently powered to reach statistical significance. The most common grade 3 or greater toxicities observed in the

treatment arms (ERBITUX plus FOLFIRI, ERBITUX plus FOLFOX, FOLFIRI alone, or FOLFOX alone) were diarrhea (22%, 14%, 15%, and 10%, respectively) and absolute neutrophil count (34%, 38%, 27%, and 36%, respectively).

Abstract #3550

In a poster session, Volker Heinemann, M.D., Ph.D., of the Ludwig-Maximilians University, Munich, Germany, presented preliminary results of a Phase II trial of ERBITUX, capecitabine (an oral fluoropyrimidine) and irinotecan (CCI) versus ERBITUX, capecitabine and oxaliplatin (CCO) as first line therapy for patients with metastatic colorectal cancer. Objective response rate was the primary endpoint of the study. A total of 92 patients were enrolled in the study; 52 were evaluable for efficacy and 74 were evaluable for toxicity. Response rate in the CCI arm was 41% (11/27) and 68% (17/51) (p=0.058) in the CCO arm. The most common Grade 3-4 toxicities observed in the CCI and the CCO-arms respectively were skin toxicity (19% vs 30%), leucopenia (11% vs 3%), diarrhea (19% vs 22%), neurotoxicity (3% vs 19%), nausea/vomiting (14% vs 16%), anemia (11% vs 0%) and pain (11% vs 5%). Overall grade 3 and 4 allergic reactions occurred in 4% and 3% of patients respectively, during the first adminstration of ERBITUX.

Abstract #3551

In a poster session, Markus Borner, M.D., of the Institute of Medical Oncology, Inselspital, Berne, Switzerland, presented preliminary results from a Swiss Group for Clinical Cancer Research randomized Phase II study of capecitabine and oxaliplatin with or without ERBITUX as first line treatment of patients with metastatic colorectal cancer. Objective response rate was the primary endpoint of the study. A total of 74 patients were recruited for the study and evaluable for preliminary response after follow up for at least nine weeks. Following a median of four treatment cycles, response rates were 43% (21/44) in the chemotherapy alone arm and 61% (23/44) in the combination ERBITUX and chemotherapy arm. The rate of disease control was 76% and 87% in the chemotherapy and chemotherapy plus ERBITUX arms, respectively. The most common grade 3 and 4 adverse reactions were diarrhea (6% vs 8%), thrombocytopenia (4% vs 1%), fatigue (1% vs 5%) and skin toxicity (0% vs 6%) in the chemotherapy and chemotherapy plus ERBITUX arms, respectively.

Abstract #3557

In a poster session, Shaker Dakhil, M.D., FACP, President, the Cancer Center of Kansas, presented preliminary results from a Phase II study of ERBITUX and FOLFOX6 as first-line therapy for metastatic colorectal cancer. The study was designed to evaluate the safety and efficacy of ERBITUX combined with FOLFOX6 in this setting. A total of 82 patients were enrolled in the study. To date, 6% of patients (4/67) evaluable for response had documented complete responses and 55% of patients (37/67) had documented partial responses. The most common grade 3 and 4 toxicities seen in greater than or equal to 5% of patients were neutropenia (44%), diarrhea (14%), rash (11%), nausea (6%), hypersensitivity (5%), acne (6%) and neurotoxicity (11%).

Abstract #3559

In a poster session, Giuseppe Colucci, M.D., Ph.D., Professor and Chairman, Oncologia Medica, Instituto Nazionale del Cancro, Bari, Italy, presented preliminary results from a Phase II study of FOLFOX-4 and ERBITUX in untreated patients with advanced colorectal cancer. Objective response rate was the primary endpoint of the study. A total of 70 patients with EGFR-

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expressing metastatic disease were enrolled in the study. To date, 67 patients are evaluable for activity. Overall, investigators observed responses in 62.7% of evaluable patients, including complete responses in 4.5% of patients (3/67), partial responses in 58.2% of patients (39/67). Stable disease was observed in 31.3% of patients (21/67). Four patients (6%) had progressive disease. To date, seven patients (10.4%) have undergone surgery of their metastases, five for liver and two for lung. The most common grade 3 and 4 toxicities were acne-like rash (20%), diarrhea (7%), leucopenia (7%) and nausea/vomiting (6%). The study is ongoing.

About ERBITUX® (Cetuximab)

ERBITUX is an IgG1 monoclonal antibody (IgG1 MAb) designed to inhibit the function of a molecular structure expressed on the surface of normal and tumor cells called the epidermal growth factor receptor (EGFR, HER1, c-ErbB-1). EGFR is part of a signaling pathway that is linked to the growth, development, and survival of many human cancer cells.  In vitro assays and in vivo animal studies have shown that binding of ERBITUX to the EGFR blocks phosphorylation, resulting in multiple EGFR mediated anti-tumor effects. Additionally, as an IgG1 MAb, ERBITUX has shown in vitro to mediate the recruitment of the body’s immune system defenses to attack cancer cells (antibody-dependent cell-mediated cytotoxicity) in certain human tumor types. While the specific mechanism of ERBITUX’ anti-tumor effect(s) in vivo is unknown, the combination of these processes may contribute to the overall therapeutic effect of ERBITUX.

ERBITUX (Cetuximab), in combination with radiation therapy, is indicated for the treatment of locally or regionally advanced squamous cell carcinoma of the head and neck. ERBITUX as a single agent is indicated for the treatment of patients with recurrent or metastatic squamous cell carcinoma of the head and neck for whom prior platinum-based therapy has failed.

ERBITUX is indicated for the treatment of EGFR-expressing, metastatic colorectal carcinoma in combination with irinotecan for patients who are refractory to irinotecan-based chemotherapy, and as a single agent for patients who are intolerant to irinotecan-based therapy. The effectiveness of ERBITUX in EGFR-expressing mCRC cancer is based on objective response rates. Currently, no data are available in mCRCthat demonstrate an improvement in disease-related symptoms or increased survival with ERBITUX.

For full prescribing information, including boxed WARNINGS regarding infusion reactions and cardiopulmonary arrest, visit http://www.ERBITUX.com.

Important Safety Information
Grade 3/4 infusion reactions, rarely with fatal outcome (<1 in 1000), occurred in approximately 3% (46/1485) of patients receiving ERBITUX (Cetuximab) therapy, characterized by rapid onset of airway obstruction (bronchospasm, stridor, hoarseness), urticaria, hypotension, and/or cardiac arrest. Severe infusion reactions require immediate and permanent discontinuation of ERBITUX therapy.

Most reactions (90%) were associated with the first infusion of ERBITUX despite the use of prophylactic antihistamines. Caution must be exercised with every ERBITUX infusion as there were patients who experienced their first severe infusion reaction during later infusions. A 1-hour observation period is recommended following the ERBITUX infusion. Longer observation periods may be required in patients who experience infusion reactions.

Cardiopulmonary arrest and/or sudden death occurred in 2% (4/208) of patients with squamous cell carcinoma of the head and neck treated with radiation therapy and

3

ERBITUX as compared to none of 212 patients treated with radiation therapy alone. ERBITUX in combination with radiation therapy should be used with caution in patients with known coronary artery disease, congestive heart failure and arrhythmias.

Close monitoring of serum electrolytes, including serum magnesium, potassium, and calcium during and after ERBITUX therapy is recommended.

Severe cases of interstitial lung disease (ILD), which was fatal in one case, occurred in less than 0.5% of 774 patients with advanced colorectal cancer (mCRC) receiving ERBITUX. There was one case of ILD reported in 796 patients with head and neck cancer receiving ERBITUX in clinical studies.

In clinical studies of ERBITUX, dermatologic toxicities, including acneform rash, skin drying and fissuring, and inflammatory and infectious sequelae (eg, blepharitis, cheilitis, cellulitis, cyst) were reported. In 208 patients receiving ERBITUX + RT, acneform rash was reported in 87% (17% severe) as compared to 10% in 212 patients treated with radiation therapy alone (1% severe). In patients receiving ERBITUX alone, 76% (N=103) experienced acneform rash (1% severe). Severe (Grade 3/4) acneform rash was reported in 11% of 774 patients with metastatic colorectal cancer treated with ERBITUX. Sun exposure may exacerbate these effects. A related nail disorder, occurring in 12% (0.4% Grade 3) of patients, was characterized as a paronychial inflammation.

The safety of ERBITUX in combination with radiation therapy and cisplatin has not been established. Death and serious cardiotoxicity were observed in a single-am trial with ERBITUX, delayed, accelerated (concomitant boost) fractionation radiation therapy, and cisplatin (100 mg/m2) conducted in patients with locally advanced squamous cell carcinoma of the head and neck. Two of 21 patients died, one as a result of pneumonia and one of an unknown cause. Four patients discontinued treatment due to adverse events. Two of these discontinuations were due to cardiac events (myocardial infarction in one patient and arrhythmia, diminished cardiac output, and hypotension in the other patient).

The incidence of hypomagnesemia (both overall and severe [NCI CTC Grades 3 & 4]) was increased in patients receiving ERBITUX alone or in combination with chemotherapy as compared to those receiving best supportive care or chemotherapy alone based on ongoing, controlled clinical trials in 244 patients. Approximately one-half of these patients receiving ERBITUX experienced hypomagnesemia and 10-15% experienced severe hypomagnesemia. Electrolyte repletion was necessary in some patients and in severe cases, intravenous replacement was required. Patients receiving ERBITUX therapy should be periodically monitored for hypomagnesemia, and accompanying hypocalcemia and hypokalemia during, and up to 8 weeks following the completion of, ERBITUX therapy.

The most serious adverse reactions associated with ERBITUX in combination with radiation therapy in 208 patients with head and neck cancer were infusion reaction (3%), cardiopulmonary arrest (2%), dermatologic toxicity (2.5%), mucositis (6%), radiation dermatitis (3%), confusion (2%), and diarrhea (2%).

The most serious adverse reactions associated with ERBITUX in mCRC clinical trials (N=774) were infusion reaction (3%), dermatologic toxicity (1%), interstitial lung disease (0.4%), fever (5%), sepsis (3%), kidney failure (2%), pulmonary embolus (1%), dehydration (5% in patients receiving ERBITUX with irinotecan, 2% in patients receiving ERBITUX as a single agent) and

4

diarrhea (6% in patients receiving ERBITUX with irinotecan, 0.2% in patients receiving ERBITUX as a single agent).

The overall incidence of late radiation toxicities (any grade) was higher with ERBITUX in combination with radiation therapy compared with radiation therapy alone. The following sites were affected: salivary glands (65%/56%), larynx (52%/36%), subcutaneous tissue (49%/45%), mucous membranes (48%/39%), esophagus (44%/35%), skin (42%/33%), brain (11%/9%), lung (11%/8%), spinal cord (4%/3%), and bone (4%/5%) in the ERBITUX and radiation versus radiation alone arms, respectively.

The incidence of Grade 3 or 4 late radiation toxicities were generally similar between the radiation therapy alone and the ERBITUX plus radiation therapy arms.

The most common adverse events seen in patients with carcinomas of the head and neck receiving ERBITUX in combination with radiation therapy (n=208) versus radiation alone (n=212) were mucositis-stomatitis (93%/94%), acneform rash (87%/10%), radiation dermatitis (86%/90%), weight loss (84%/72%), xerostomia (72%/71%), dysphagia (65%/63%), asthenia (56%/49%), nausea (49%/37%), constipation (35%/30%) and vomiting (29%/23%). The most common adverse events seen in patients receiving ERBITUX as a single agent (N=103) were acneform rash (76%), asthenia (45%), pain (28%), fever (27%) and weight loss (27%).

The most common adverse events seen in patients receiving ERBITUX with irinotecan (n=354) or ERBITUX as a single agent (n=420) were acneform rash (88%/90%), asthenia/malaise (73%/48%), diarrhea (72%/25%), nausea (55%/29%), abdominal pain (45%/26%), vomiting (41%/25%), fever (34%/27%), constipation (30%/26%), and headache (14%/26%).

About Colorectal Cancer

In the U.S., approximately 149,000 people will be diagnosed with cancer of the colon or rectum this year. Half of these patients have metastatic disease, or cancer that has spread to other organs, at the time of diagnosis. EGFR is expressed in up to 77.7 % of colorectal cancer tumors. Colorectal cancer is the third most common cancer in both men and women.(1)

About ImClone Systems

ImClone Systems Incorporated is committed to advancing oncology care by developing 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’ strategy is to become a fully integrated biopharmaceutical company, taking its development programs from the research stage to the market. ImClone Systems’ headquarters and research operations are located in New York City, with additional administration and manufacturing facilities in Branchburg, New Jersey.

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

5

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.

#   #   #

(1)           American Cancer Society: Cancer Facts and Figures 2006.
http://www.cancer.org/downloads/STT/CAFF2006PWSecured.pdf. Accessed 5/16/06.

6