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Two Phase 3 Studies of Cetuximab Demonstrate Different Overall Survival Rates
A randomized, multicenter, Phase III trial (NCIC CTG CO.17) compared Erbitux plus best supportive care to best supportive care alone in 572 patients with metastatic colorectal cancer whose disease was refractory to all available chemotherapy, including irinotecan, oxaliplatin, and fluoropyrimidines. The study, conducted by the National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) in collaboration with the Australasian Gastro-Intestinal Trials Group (AGITG), met its primary efficacy endpoint showing a statistically significant improvement in overall survival. These are the first data of an anticancer therapy to demonstrate overall survival in this refractory treatment setting. The NCIC CTG is scheduled to submit the data from this study for presentation at a major medical meeting in 2007.
"This is the second tumor type where Erbitux has shown survival benefit," said Eric Rowinsky, M.D., Chief Medical Officer and Senior Vice President of ImClone Systems. "Additionally, no other EGFR-targeted therapy has demonstrated an improvement in overall survival in a Phase III colorectal cancer clinical study."
A second Phase III, randomized study, known as the Erbitux Plus Irinotecan in Colorectal Cancer (EPIC), compared irinotecan to irinotecan plus Erbitux in approximately 1,300 patients whose disease was not responding to first-line oxaliplatin-based chemotherapy. After randomization, patients were treated until their disease progressed. Upon disease progression, study treatment was stopped and further treatment was at the discretion of the physician.
Secondary efficacy endpoints (progression free survival, response rate) strongly favored the combination of Erbitux plus irinotecan over irinotecan alone; however, the primary endpoint (overall survival) was not met.
Efforts to interpret these confounded results are ongoing. A preliminary review of the data reveal that a considerable number of patients randomized to the irinotecan arm went on to receive Erbitux with or without irinotecan after failing irinotecan alone.
"The studies provide important new information for patients with advanced colorectal cancer, and are part of our comprehensive clinical development program designed to fully understand the potential uses of Erbitux for cancer patients," said Martin Birkhofer, M.D., Vice President, Oncology Global Medical Affairs, Bristol-Myers Squibb. "We look forward to our full analysis of the data, and to sharing the results with the scientific community at a major medical meeting."
"We are encouraged by the totality of the results from both studies and we plan to have discussions with the Food and Drug Administration concerning a registrational submission," said Eric Rowinsky, M.D. Chief Medical Officer and Senior Vice President of ImClone Systems.
About Erbitux® (Cetuximab)
Erbitux is a 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). In vitro assays and in vivo animal studies have shown that binding of Erbitux to the EGFR blocks phosphorylation and activation of receptor-associated kinases, resulting in inhibition of cell growth, induction of apoptosis, and decreased matrix metalloproteinase and vascular endothelial growth factor production. In vitro, Erbitux can mediate antibody-dependent cellular cytotoxicity (ADCC) against certain human tumor types. While the mechanism of Erbitux' anti-tumor effect(s) in vivo is unknown, all of these processes may contribute to the overall therapeutic effect of Erbitux. EGFR is part of a signaling pathway that is linked to the growth and development of many human cancers, including those of the head and neck, colon and rectum.
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 (mCRC) 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 for the treatment of EGFR-expressing mCRC cancer is based on objective response rates. Currently, no data are available that demonstrate an improvement in disease-related symptoms or increased survival with Erbitux for the treatment of EGFR-expressing mCRC.
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 (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. 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 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). In patients with mCRC, acneform rash was reported in 89% (686/774) of all treated patients, and was severe in 11% (84/774). Subsequent to the development of severe dermatologic toxicities, complications including S. aureus sepsis and abscesses requiring incision and drainage were reported. 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.
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 with carcinomas of the head and neck 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 with mCRC 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.
Source: ImClone Systems