IMMU drug shows promising results in small adjuvant colorectal trial:
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Phase-II Trial Shows Improved Survival of Colorectal Cancer Patients Receiving Radioimmunotherapy Post Salvage Resection of Liver Metastases
- German Study Results Published in Journal of Clinical Oncology -
GOTTINGEN, Germany, Sept. 21 /PRNewswire/ -- The University of Gottingen today announced that the results of a five-year study conducted at this German university's Departments of General Surgery and Nuclear Medicine were published in the September 20th issue of The Journal of Clinical Oncology, a publication of the American Society of Clinical Oncology. The authors reported that they treated 23 colorectal cancer patients with a radioactive, humanized, antibody against carcinoembryonic antigen (CEA), which is expressed by more than 90% of colorectal cancers, after the patients had complete resection of their liver metastases by these surgeons. The investigators found that those treated after surgery with one injection of this 131I-labeled labetuzumab antibody, developed by Immunomedics, Inc. (Nasdaq: IMMU ), survived twice as long (68 months median survival) than either historical controls or a contemporaneous control group of patients receiving either chemotherapy or no therapy (31 months median survival) at this hospital. The median follow-up time in this trial was a little over 5 years (64 months). In the evaluable population of 19 patients, the five-year survival rate was 51.3%. The major adverse event was transient myelosuppression, mostly in a drop in white blood cells and/or platelets.
The study's principal investigators, Dr. Torsten Liersch (Department of General Surgery) and Dr. Johannes Meller (head of the Department of Nuclear Medicine of the University of Gottingen), commented: "These are the best results we know so far for the adjuvant, or post-operative treatment, of patients having their liver metastases of colorectal cancer resected. In most other trials reported, the median survival after resection of these metastases, even with post-operative chemotherapy, is between 28 and 41 months, when about 25%-37% of the patients survive five years. These initial trial results with radiolabeled labetuzumab confirm animal and earlier clinical studies showing a benefit for this treatment in the setting of micrometastatic disease, which we presume is present in patients having their liver metastases removed, since over two-thirds usually relapse between 2 and 5 years later."
"These striking results encourage us to proceed to a randomized trial, comparing 131I-labetuzumab to post-operative chemotherapy or to the combination of radioimmunotherapy and chemotherapy in colorectal cancer patients having resection of their liver metastases," added Professor Heinz Becker, M.D., Director of the Department of General Surgery, and a co-investigator of this study.
Reference:
T. Liersch, J. Meller, B. Kulle, T.M. Behr, P. Markus, C. Langer, B.M. Ghadimi, W.A. Wegener, J. Kovacs, I.D. Horak, H. Becker, and D.M. Goldenberg. Phase II Trial of Carcinoembryonic Antigen Radioimmunotherapy With 131I- labetuzumab After Salvage Resection of Colorectal Metastases in the Liver: Five-Year Safety and Efficacy Results. J Clin Oncol 2005; 23(27): 6763-6770.
About Colorectal Cancer
Colorectal cancer is responsible for more than 15% of all malignancies in the United States and Europe, afflicting about 147,000 Americans and killing approximately 57,000 in 2004; it is the third most frequent cancer killer in our society. The liver is the most common site of distant spread, or metastasis, affecting up to 60% of colorectal cancer patients (at least 50,000 is the USA). The five-year survival rate, irrespective of any form of therapy other than surgery, is close to zero in patients with liver metastases, and after resection of liver tumors in patients who are amenable to complete surgical removal of metastatic liver disease, the 5-year survival rate has been reported to be between 25% and 37% at specialized centers, but with tumor relapse occurring in the majority of patients. Since about two-thirds of resected colorectal cancer patients eventually relapse, with more than half first experiencing a recurrence in the liver, current thought is that clusters of tumor cells are trapped selectively in the liver, where they then expand to form liver metastases. Therefore, methods to selectively and timely destroy these clusters of cancer cells are needed, so that surgical efforts can be more successful.
About 131I-labetuzumab
Labetuzumab is Immunomedics' proprietary, humanized, monoclonal antibody targeting a specific site on carcinoembryonic antigen (CEA) that is associated with over 90% of colorectal cancers, even when they spread to the liver and other organs. The antibody, labeled with a therapeutic radioisotope, iodine- 131, is able to target and destroy clusters of CEA-expressing cancer cells, as demonstrated previously in preclinical studies involving human colonic cancers grafted to immunosuppressed mice, where cures were achieved after giving the therapeutic to mice with disseminated, or metastatic, disease. Since the radioactivity passes through the blood as the antibody distributes throughout the body, compartments rich in blood, such as the bone marrow, received radioactivity, but at lower doses than to cancer cells. This results in the transient hematological depression observed in patients at the radiation doses delivered. Studies are now in progress to assess the safety and efficacy of repeated doses of this radioactive antibody following resection of liver metastases in colorectal cancer patients.
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