Effect of zoledronate on persisting isolated tumour cells in patients with early breast cancer.

BACKGROUND: There is strong evidence for the isolated tumour cells (ITCs) in the bone marrow of breast cancer patients having prognostic impact both at primary diagnosis and during recurrence-free follow-up. The goal of this study was to investigate the therapeutic efficacy of zoledronate on the persistence of ITC. PATIENTS AND METHODS: A total of 172 primary breast cancer patients without evidence of distant recurrence but detection of ITC in bone marrow were followed up. Zoledronate was administered every 4 weeks for 6 months to 31 patients who had completed surgery and adjuvant chemotherapy. In a matched-pair analysis, these patients were compared to 141 patients who did not receive additional zoledronate treatment. The bone marrow was re-examined after a median of 7.9 months (SD 0.89) and 11.5 months (SD 12.41; p=0.11), respectively. Patients were followed-up prospectively for a median of 39 months after the first aspiration. RESULTS: While ITCs were detected in all 172 patients at the time of first bone marrow aspiration, ITCs were detected in four patients (13%) following 6 months of zoledronate therapy in contrast to 38 patients (27%) of the control group (p=0.099). The reduction in cell numbers between the first and second aspiration reached statistical significance in the zoledronate group (p=0.02 vs. p=0.14). Persistent ITCs at the follow-up aspiration were associated with reduced recurrence-free survival (p=0.05). CONCLUSION: These results indicate a potential antineoplastic effect of the cell cycle-independent agent zoledronate on persisting ITCs in a dormant state.

Phase I trial of the trifunctional anti-HER2 x anti-CD3 antibody ertumaxomab in metastatic breast cancer.

PURPOSE: Ertumaxomab is an intact bispecific antibody targeting HER2/neu and CD3 with selective binding to activatory Fcgamma type I/III receptors, resulting in the formation of a tri-cell complex between tumor cells, T cells, and accessory cells. Patients with metastatic breast cancer were enrolled into a multicenter phase I dose-escalating trial. EXPERIMENTAL DESIGN: Three ascending doses of ertumaxomab (10-200 microg) were administered i.v. on day 1, 7 +/- 1, and 13 +/- 1. Safety and tolerability were the primary objectives. Secondary objectives were antitumor activity and different immunologic variables. RESULTS: Fifteen out of 17 enrolled patients completed the study. One hundred micrograms was identified as the maximal tolerable single dose. Most drug-related adverse events were mild and transient including fever (94%), rigors (47%), headache (35%), nausea (29%), vomiting (29%). Grades 3 and 4 (Common Toxicity Criteria) were lymphocytopenia (76%) and elevation of liver enzymes (47%). One patient (200 mug dose) developed severe hypotension and respiratory distress syndrome, another patient (150 mug dose) developed a systemic inflammatory response syndrome and acute renal failure. Aggravation of congestive heart failure was seen in one patient with preexisting ventricular dysfunction after administration of the third dose (200 microg). All adverse events were fully reversible. Antitumor response was seen in 5 out of 15 evaluable patients (one with a complete response, two with partial responses, two with stable disease) at dose levels of > or = 100 microg. Measurements of cytokines (interleukin-6, interleukin-2, tumor necrosis factor-alpha, and IFN-gamma) suggest a strong T helper cell type 1-associated immune response. The induction of human anti-mouse/anti-rat antibodies was detected in 5 out of 16 (31%) patients. DISCUSSION: Treatment with triple infusions of ertumaxomab yields a strong immunologic response. Doses up to 100 microg can be safely infused with close monitoring of patients. The observed clinical responses are encouraging and indicate antitumor efficacy.