Department of Haematology/Oncology, Ruhr-University Bochum, Marienhospital I Herne, Herne, Germany
Received 25 April 2001; revised 7 January 2002; accepted 11 February 2002
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The aim of our study was to evaluate the efficacy of the monoclonal antibody edrecolomab after chemo- and radiotherapy in the elimination of disseminated tumour cells in bone marrow in the adjuvant therapy of breast cancer.
Patients and methods:
The bone marrow of 25 patients with breast cancer was tested for the presence of disseminated tumour cells using the pancytoceratine antibody and the alkaline phosphataseanti-alkaline-phosphatase (APAAP) technique. To characterize tumour cells simultaneously, immunofluorescent double labelling of pancytoceratine and epithelial cell adhesion molecule (antibody 17-1A) was performed on tumour cells after magneto bead enrichment. Patients positive for the 17-1A antigen in bone marrow after chemotherapy were treated with edrecolomab (500 mg Panorex® initially, then 100 mg/month over 4 months) and investigated for the presence of micrometastases 6 weeks after the last treatment.
Results:
Of the 17 patients showing bone marrow micrometastases (BM-MM), 14 tested 17-1A positive before adjuvant chemotherapy. After chemotherapy, nine patients remained positive for the 17-1A antigen and were treated with edrecolomab. The final investigation after immunotherapy showed a complete elimination of the 17-1A-positive BM-MM in seven patients and a significant reduction of these cells in two patients.
Conclusions:
Sequential treatment of breast cancer with edrecolomab after adjuvant chemotherapy can reduce disseminated tumour cells in the bone marrow and eliminate 17-1A-positive micrometastases.
Key words: 17-1A antigen, bone marrow, breast cancer, disseminated tumour cells, immunotherapy
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
There is emerging evidence that the presence of disseminated tumour cells in bone marrow is a prognostic factor in cancer, particularly in breast cancer [26]. Epithelial tumour cells are able to be disseminated to secondary organs at an early stage of primary tumour development. The data that are currently available suggest that bone marrow micrometastases (BM-MM) represent a select population of dormant cells that can lead to early relapses of the disease [6].
The efficacy of chemotherapy on these tumour cells is limited because of their predominantly dormant non-proliferating status [79]; therefore, adjuvant treatment against these tumour cells is of great interest. Treatment with the monoclonal antibody edrecolomab has been reported to kill quiescent tumour cells, despite their resistance to chemotherapy [10]. Nevertheless, the potential benefit of edrecolomab is controversial. While Riethmüller et al. demonstrated its efficacy in a 7-year follow-up, with a 32% reduction in the overall mortality in colon cancer patients [11, 12], Punt et al. [13] demonstrated that the addition of edrecolomab to 5-FU/LV in the adjuvant treatment of stage III colon cancer did not improve overall survival. Braun investigated the efficacy of edrecolomab on disseminated tumour cells in 10 patients with advanced breast cancer in the metastatic state, and showed a complete elimination of epithelial cell adhesion molecule (EpCAM)-positive cells in four patients [14, 15].
The aim of our study was to evaluate the efficacy of the monoclonal antibody edrecolomab in the elimination of disseminated tumour cells in bone marrow in the adjuvant therapy of breast cancer.
![]() |
Patients and methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
BM-MM were detected by pancytoceratine antibody (A45-B/B3) and visualized by the alkaline phosphataseanti-alkaline-phosphatase technique (APAAP) as described by Cordell et al. [16] and Braun et al. [14]. To characterize tumour cells, simultaneous immunofluorescent double labeling of pancytokeratine and EpCAM (antibody 17-1A) was performed on tumour cells after magneto bead enrichment as described by Naume et al. [17] and Braun et al. [15]. After permeabilization with 0.1% Triton X-100 and fixation with 1.0% paraformaldehyde, the immunocytochemical double-labeling technique was performed by a simultaneous incubation with alkaline phosphatase-conjugated anti CK A45-B/B3 Fab fragments and the anti EpCAM immunoglobulin edrecolomab. After co-incubation of the antibody conjugates, specific goat antimouse immunoglobulins conjugated with colloidal gold particles were added to specifically label murine edrecolomab [15]. After washing steps and fixation, silver development was carried out and terminated under the microscope as soon as silver precipitates became visible.
In cases of cytokeratine-positive BM-MM with 17-1A antigen expression after the adjuvant chemotherapy, the efficacy of an additional therapy with the monoclonal antibody 17-1A edrecolomab was investigated.
The initial dose of edrecolomab (Panorex®) was 500 mg, followed by 100 mg/month over 5 months.
Main target parameters of the study were the evidence of disseminated tumour cells in newly diagnosed breast cancer patients, and the prevalence of BM-MM with 17-1A antigen expression before and after adjuvant chemotherapy and additional immunotherapy. In addition, the tolerance of patients to immunotherapy and the clinical follow-up were investigated.
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
|
|
|
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
New therapeutic strategies to prevent metastatic relapse in patients with operable primary carcinomas, such as immunotherapy with the monoclonal antibody edrecolomab, are still controversial [1113].
Edrecolomab is a mouse-derived monoclonal IgG 2a antibody [10, 21]. It recognizes the human tumour-associated antigen Co 17-1A, which is expressed on the surface of a wide variety of tumour cells, and appears to be related to the presence of well differentiated tumours [10].
The immunotherapeutic agent is thought to destroy tumour cells by activating an array of endogenous cytotoxic mechanisms, including antibody-dependent cell-mediated cytotoxicity and possibly antibody-dependent complement-mediated cytotoxicity. Edrecolomab may induce antitumour activity indirectly by inducing a host anti-idiotypic response.
In clinical practice, edrecolomab was first used by Riethmüller et al. [11] for the adjuvant treatment of colon cancer. In their study, the intention-to-treat analysis showed a significant effect on overall and disease-free survival, with a decreased recurrence rate of 25% and a 32% reduction in overall mortality in colon cancer patients. The presence of the 17-1A surface adhesion molecule on disseminated tumour cells, identified by immunocytological methods, has been demonstrated in 50% of breast cancer patients and 60% of disseminated tumour cells.
Braun et al. [14] showed how a single edrecolomab application (1 x 500 mg) in patients with metastatic breast cancer could result in 17-1A-positive tumour cells being significantly reduced in four of the eight patients tested and eliminated completely in the remaining four. We have confirmed these results in this study of nine patients with 17-1A-positive BM-MM in the adjuvant breast cancer setting, using the recommended multiple application of edrecolomab (1 x 500 mg plus 4 x 100 mg). No correlation could be found between tumour grading, tumour size or the presence of metastatic enlarged lymph nodes and the presence of disseminated tumour cells before edrecolomab therapy. Bearing in mind the small number of patients in our study, our results demonstrate that use of the recommended multiple dose regimen of edrecolomab could achieve a complete elimination of 17-1A-positive BM-MM in 78% of patients and a significant reduction in 22%. The additional benefit of 28% compared with Brauns investigation (which showed only 50% complete elimination) may be due to the multiple dose application of edrecolomab. The immunotherapy was very well tolerated and had no side effects.
Despite the results discussed above, none of the nine patients showed a complete reduction in the number of disseminated tumour cells after tumour cell enrichment. Nevertheless, the prognostic value of the evidence of the cells by means of this method has not yet been fully determined; for example, Mansi et al. described a spontaneous loss of BM-MM over time [22]. We showed using APAAP immunostaining that five of the nine patients (56%) were completely negative for BM-MM after edrecolomab therapy. If this testing alone were considered to have a prognostic value, the complete elimination of 56% of BM-MM would demonstrate that cure of breast cancer by means of additional immunotherapy might be possible. On the other hand tumour cell enrichment, now valuable for improving detection of disseminated tumour cells, showed only a selective elimination of 17-1A-positive BM-MM, an argument against the statement of Mansi et al. [22]. The selective disappearance of 17-1A-positive tumour cells is unlikely to have occurred spontaneously in patients with BM-MM. Taking into consideration that fact that two of our nine patients showed a significant reduction in the number of 17-1A-positive tumour cells, our results also revealed evidence of other 17-1A-negative tumour cells in bone marrow after immunotherapy using an immunomagnetic technique. The efficacy of edrecolomab is evidently due to its selection of 17-1A-positive cells. This may be explained by Brauns theory that the tumour cell antigen heterogeneity of disseminated tumour cells limits the efficacy of monovalent immunotherapeutic strategies directed against only one particular antigen. Therefore, new immunotherapeutic strategies should be developed to detect and eliminate these cells [7]. Because of the small number of patients we cannot definitely exclude that some of them could have been negative purely by chance or methodological variability. On the other hand it seems more unlikely that the elimination of 17-1A-positive cells after antibody application occurred purely by chance.
The follow-up to our data will demonstrate the significance of both tumour cell enrichment and APAAP immunostaining with regard to the prognostic value.
One limitation of our study is that we cannot definitely exclude a biased endocrine effect of adjuvant chemotherapy. An additional endocrine effect of chemotherapy-induced cessation of ovarian function may in part explain the delayed disappearance of 17-1A-positive cells, particularly since six out of nine patients were hormone receptor positive.
In conclusion, sequential treatment of breast cancer with edrecolomab after adjuvant chemotherapy can reduce the number of tumour cells in bone marrow and eliminate 17-1A-positive cells in breast cancer. This therapy is very well tolerated, which is highly important in the adjuvant situation. Further investigations are ongoing, correlating these data with disease-free and overall survival of the patients in this study.
![]() |
Footnotes |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
2. Braun S, Pantel K. Biological characteristics of micrometastatic cancer cells in bone marrow. Cancer Metastasis Rev 1999; 18: 7590.[ISI][Medline]
3. Braun S, Pantel K. Prognostic significance of micrometastatic bone marrow involvement. Breast Cancer Res Treat 1998; 52: 201216.[ISI][Medline]
4. Braun S, Pantel K. Micrometastatic bone marrow involvement: detection and prognostic significance. Med Oncol 1999; 16: 154165.[ISI][Medline]
5. Cote RJ, Rosen PP, Hakes TB et al. Monoclonal antibodies detect occult breast carcinoma metastases in the bone marrow of patients with early stage disease. Am J Surg Pathol 1988; 12: 333340.[ISI][Medline]
6. Diel IJ, Kaufmann M, Costa SD et al. Micrometastatic breast cancer cells in bone marrow at primary surgery: Prognostic value in comparison with nodal status. J Natl Cancer Inst 1996; 88: 16521664.
7. Braun S, Hepp F, Sommer H, Pantel K. Tumor-antigen heterogeneity of disseminated breast cancer cells: implications for immunotherapy of minimal residual disease. Int J Cancer (Pred Oncol) 1999; 84: 15.[ISI][Medline]
8. Braun S, Kentenich C, Janni W et al. Lack of effect of adjuvant chemotherapy on the elimination of single dormant tumor cells in bone marrow of high-risk breast cancer patients. J Clin Oncol 2000; 18: 8086.
9. Fidler IJ. Modulation of the organ environment for treatment of cancer metastases. J Natl Cancer Inst 1995; 87: 15881592.[ISI][Medline]
10. Adkins JC, Spencer CM. Edrecolomab (monoclonal antibody 17-1A). Drugs 1998; 56: 619626.[ISI][Medline]
11. Riethmüller G, Schneider E, Schlimok G et al. Randomised trial of monoclonal antibody for adjuvant therapy of resected Dukes C colorectal carcinoma. Lancet 1994; 343: 11771183.[ISI][Medline]
12. Riethmüller G, Holz E, Schlimok G et al. Monoclonal antibody therapy for resected Dukes C colorectal cancer: seven-year outcome of a multicenter randomized trial. J Clin Oncol 1998; 16: 17881794.[Abstract]
13. Punt CJ, Nagy A, Douillard J et al. Edrecolomab (17-1A antibody) alone or in combination with 5-fluorouracil based chemotherapy in the adjuvant treatment of stage III colon cancer: results of a phase III study. Proc Am Soc Clin Oncol 2001; 20: 123a (Abstr 487).
14. Braun S, Janni W, Hepp F et al. Monitoring of reduction of 17-1A-expressing breast cancer micrometastases (BC-MM) during antibody therapy with edrecolomaba pilot study. Proc Am Soc Clin Oncol 1999; 18: 448a (Abstr 1728).
15. Braun S, Hepp F, Kentenich CRM et al. Monoclonal antibody therapy with edrecolomab in breast cancer patients: monitoring of elimination of disseminated cytokeratin-positive tumor cells in bone marrow. Clin Cancer Res 1999; 5: 39994004.
16. Cordell JL, Falini B, Erber WN et al. Immunoenzymatic labeling of monoclonal antibodies using immune complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase (APAAP complexes). J Histochem Cytochem 1984; 32: 219229.[Abstract]
17. Naume B, Borgen E, Beiske K et al. Immunomagnetic techniques for the enrichment and detection of isolated breast carcinoma cells in bone marrow and peripheral blood. J Hematother 1997; 6: 103114.[ISI][Medline]
18. Funke I, Fries S, Rolle M et al. Comparative analyses of bone marrow micrometastases in breast and gastric cancer. Int J Cancer 1996; 65: 755761.[ISI][Medline]
19. Pantel K, Schlimok G, Braun S et al. Differential expression of proliferation-associated molecules in individual micrometastatic carcinoma cells. J Natl Cancer Inst 1993; 85: 14191424.[Abstract]
20. Pantel K, Schlimok G, Angstwurm M et al. Methodological analysis of immunocytochemical screening for disseminated epithelial tumor cells in bone marrow. J Hematother 1994; 3: 165173.[Medline]
21. Göttlinger HG, Funke I, Johnson JP et al. The epithelial cell surface antigen 17-1A, a target for antibody-mediated tumor therapy: its biochemical nature, tissue distribution and recognition by different monoclonal antibodies. Int J Cancer 1986; 38: 4753.[ISI][Medline]
22. Mansi JL, Berger U, Mc Donnell T et al. The fate of bone marrow micrometastases in patients with primary breast cancer. J Clin Oncol 1989; 7: 445449.[Abstract]