Bendamustine as salvage treatment in patients with advanced progressive breast cancer: a phase II study

A phase II pilot study of bendamustine as salvage treatment in patients with advanced breast cancer was performed to determine the objective response rates and make further observations on the toxicity of this drug. A group of 37 patients, pretreated with chemotherapy for advanced disease, entered the trial. Treatment consisted of 150 mg/m2 bendamustine on days 1 and 2 of a 4-week treatment course. Patients continued to receive treatment until complete remission and then two further courses, until tumour progression or unacceptable toxicity ensued. A total of 36 patients received at least one treatment course and were assessable for toxicity; 33 patients were evaluable for treatment results. Dose-limiting grade 3 and 4 WHO toxicity occurred in 5 and 3 patients respectively; 27% of patients entered complete or partial tumour remission. The median time to tumour progression was 2 months with a range of 1-14 months. The efficacy of bendamustine was apparently independent of pretreatment with anthracyclines, suggesting a lack of cross-resistance between bendamustine and anthracyclines. It can be concluded that bendamustine in the dose and application schedule used here is active in the salvage therapy of women with advanced breast cancer. The toxicity was acceptable. Future studies have to confirm the data of this pilot trial and to define the role of bendamustine in the combination chemotherapy of metastatic breast cancer that has been suggested by previous trials.