ERBITUX(R) Data on Locoregional Control and Overall Survival in Phase III Head and Neck Cancer Study Presented at AACR-NCI-EORTC Meeting

ImClone Systems Incorporated (NASDAQ: IMCL) today announcedindependently reviewed results from an international, randomized phaseIII study examining ERBITUX(R) (Cetuximab), an IgG1 monoclonalantibody, combined with radiation (n=211) versus radiation alone(n=213) in patients with locoregionally advanced squamous cellcarcinoma of the head and neck. The study demonstrated that theaddition of ERBITUX to radiation resulted in a 9.5 month improvementin median duration of locoregional control, or the prevention of thespread of cancer beyond the head and neck region, and a 19.7 monthimprovement in median survival when compared to radiation alone; bothresults were statistically significant. These results were presentedtoday at the AACR-NCI-EORTC International Conference on MolecularTargets and Cancer Therapeutics in Philadelphia.

Treatment of patients with ERBITUX plus radiation resulted in a32% reduction in the risk of locoregional recurrence compared toradiation alone (hazard ratio, 0.68 (95% CI 0.52-0.89)). The medianduration of locoregional control was 24.4 months with ERBITUX plusradiation versus 14.9 months with radiation alone (log-rank pvalue = 0.005).

The median overall survival with radiation plus ERBITUX was 49.0months versus 29.3 months for radiation alone (hazard ratio, 0.74 (95%CI 0.56-0.97); log-rank p value = 0.03). In addition, there was anadvantage for the ERBITUX regimen over radiation alone in the 3-yearsurvival rates (56.1% versus 45.0%, respectively).

With the exception of acneiform rash and infusion reactions, theincidence of grade 3 or greater toxicity, including mucositis, whichoften precludes combining chemotherapies with radiation, did notdiffer significantly between the treatment arms.

According to the American Cancer Society, approximately 40,000Americans will be diagnosed with head and neck cancer this year,including cancers of the tongue, mouth, pharynx, and larynx. Inaddition, it is estimated that more than 11,000 Americans will diefrom the disease in 2005.

"Radiation therapy or radiation therapy combined with chemotherapyare the principal treatment options in this disease type," said JamesBonner, M.D., University of Alabama, principal investigator for thestudy. "If approved, ERBITUX added to radiation may represent analternative treatment option for patients with head and neck cancer."

This study and other ERBITUX study data are included in regulatoryapplications in various countries, including a supplemental BiologicsLicense Application (sBLA) that was recently accepted for filing bythe U.S. Food and Drug Administration (FDA). The U.S. application wasgranted priority review, a designation given to drugs that potentiallyoffer a significant therapeutic advance over existing therapies forserious or life-threatening diseases. Based on the priority reviewdesignation, the FDA has until March 1, 2006 to take action on thesBLA filing. Merck KGaA has submitted applications to the EuropeanAgency for Evaluation of Medicinal Products (EMEA), the pharmaceuticalregulatory body of the E.U., and to Swissmedic, the Swiss agency fortherapeutic products.

About the 9815 Study

The phase III trial (IMCL-9815) included 424 patients withadvanced squamous cell carcinoma of the oropharynx (area of the throatat the back of the mouth), larynx (voice box) or hypopharynx (cavityat the back of the mouth that opens into the esophagus) that hasspread through the head and neck region. Patients were randomized toreceive radiation plus weekly ERBITUX therapy (n=211) or radiationalone (n=213) for six to seven weeks. Initial findings from study 9815were presented at the American Society of Clinical Oncology (ASCO)annual meeting in 2004.

About ERBITUX(R) (Cetuximab)

On February 12, 2004, the FDA approved ERBITUX for use in theUnited States in combination with irinotecan in the treatment ofpatients with EGFR-expressing, metastatic colorectal cancer who arerefractory to irinotecan-based chemotherapy and for use as a singleagent in the treatment of patients with EGFR-expressing, metastaticcolorectal cancer who are intolerant to irinotecan-based chemotherapy.The effectiveness of ERBITUX for the treatment of colorectal cancer isbased on objective response rates. Currently, no data are availablethat demonstrate an improvement in disease-related symptoms orincreased survival with ERBITUX in metastatic colorectal cancerpatients.

ERBITUX binds specifically to epidermal growth factor receptor(EGFR, HER1, c-ErbB-1) on both normal and tumor cells, andcompetitively inhibits the binding of epidermal growth factor (EGF)and other ligands, such as transforming growth factor-alpha. The EGFRis constitutively expressed in many normal epithelial tissues,including the skin and hair follicle. Over-expression of EGFR is alsodetected in many human cancers including those of the colon andrectum.

Important Safety Information

Severe infusion reactions, rarely fatal and characterized by rapidonset of airway obstruction (bronchospasm, stridor, hoarseness),urticaria, and hypotension, have occurred in approximately 3% (20/774)of patients with the administration of ERBITUX. Most reactions (90%)were associated with the first infusion of ERBITUX despite the use ofprophylactic antihistamines. Severe infusion reactions requireimmediate and permanent discontinuation of ERBITUX therapy. Cautionmust be exercised with every ERBITUX infusion as there were patientswho experienced their first severe infusion reaction during laterinfusions. A 1-hour observation period is recommended following theERBITUX infusion. Longer observation periods may be required inpatients who experience infusion reactions.

Severe cases of interstitial lung disease (ILD), which was fatalin one case, occurred in less than 0.5% of 774 patients receivingERBITUX.

Dermatologic toxicities, including acneform rash (11% of 774patients, grade 3/4), skin drying and fissuring, inflammatory orinfectious sequelae (e.g., blepharitis, cheilitis, cellulitis, cyst)and paronychial inflammation (0.4% of 774 patients, grade 3) werereported. Sun exposure may exacerbate any skin reactions.

Hypomagnesemia has been reported with ERBITUX when administered asa single agent and in combination with multiple differentchemotherapeutic regimens. The incidence of hypomagnesemia (bothoverall and severe (NCI CTC grades 3 & 4)) was increased in patientsreceiving ERBITUX alone or in combination with chemotherapy ascompared to those receiving best supportive care or chemotherapy alonebased on ongoing, controlled clinical trials in 244 patients.Approximately one-half of these patients receiving ERBITUX experiencedhypomagnesemia and 10-15% experienced severe hypomagnesemia.Electrolyte repletion was necessary in some patients, and in severecases, intravenous replacement was required. Patients receivingERBITUX therapy should be periodically monitored for hypomagnesemia,and accompanying hypocalcemia and hypokalemia during, and up to 8weeks following the completion of, ERBITUX therapy.

Other serious adverse events associated with ERBITUX in clinicaltrials (n=774) were fever (5%), sepsis (3%), kidney failure (2%),pulmonary embolus (1%), dehydration (5% in patients receiving ERBITUXplus irinotecan, 2% receiving ERBITUX as a single agent) and diarrhea(6% in patients receiving ERBITUX plus irinotecan, 0.2% with ERBITUXas a single agent).

Additional common adverse events seen in patients receivingERBITUX plus 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%).

Full prescribing information, including boxed WARNING regardinginfusion reactions, is available upon request or by visitingwww.ERBITUX.com.

About ImClone Systems Incorporated

ImClone Systems Incorporated is committed to advancing oncologycare by developing a portfolio of targeted biologic treatments,designed to address the medical needs of patients with a variety ofcancers. The Company's research and development programs includegrowth 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 inNew York City, with additional administration and manufacturingfacilities in Branchburg, New Jersey.

Certain matters discussed in this news release may constituteforward- looking statements within the meaning of the PrivateSecurities Litigation Reform Act of 1995 and the Federal securitieslaws. Although the company believes that the expectations reflected insuch forward-looking statements are based upon reasonable assumptionsit can give no assurance that its expectations will be achieved.Forward-looking information is subject to certain risks, trends anduncertainties that could cause actual results to differ materiallyfrom those projected. Many of these factors are beyond the company'sability to control or predict. Important factors that may cause actualresults to differ materially and could impact the company and thestatements contained in this news release can be found in thecompany's filings with the Securities and Exchange Commissionincluding quarterly reports on Form 10-Q, current reports on Form 8-Kand annual reports on Form 10-K. For forward-looking statements inthis news release, the company claims the protection of the safeharbor for forward-looking statements contained in the PrivateSecurities Litigation Reform Act of 1995. The company assumes noobligation to update or supplement any forward-looking statementswhether as a result of new information, future events or otherwise.