Serological Her2/neu-determination in patients receiving Herceptin^®

Objective

Treatment with Herceptin^® is one of the most promising therapies for patients with metastatic breast cancer whose tumors overexpress the HER2/neu protein. Recent studies provide evidence that patients receiving herceptin have a significant benefit. Taking into account this clinical success and, additionally, the favorable side-effect pattern, addition of Herceptin in first-line treatment of metastatic breast cancer is considered the most encouraging therapeutic option. However, prognostic and/or predictive markers justifying the therapy have not been available until now. Therefore, we designed a retrospective study in order to evaluate the serological Her2/neu determination accompanying a Herceptin therapy.

Method

The sera samples of 10 Herceptin-patients were collected immediately after standard hematological investigation. Serological Her2/neu was quantified using the Her2/neu Kit (Bayer Diagnostics, Munich, Germany). Automatical determination was performed on the immunoanalyzer Bayer Immuno1™. The valueswere analyzed in terms of the clinical course of each patient. Each assay was performed in duplicate.

Results

The 10 patients were observed 15 months (median), range 6-21. Two patients had visceral metastases, two patients bone metastases and six patients developed multiple occult metastases. Seven patients had suffered a relapse. In all these seven patients the serological Her2/neu concentration increased strikingly at time of progress. The Her2/neu levels of the three patients with stable disease did not change during the observation period.

Conclusion

Serological Her2/neu concentrations paralleled the clinical course of a patient with metastatic breast cancer receiving Herceptin therapy. Prospective studies should be designed in order to demonstrate the prognostic/predictive value of serological Her2/neu determination.