Temozolomide in metastatic breast cancer (MBC): A phase II trial of the National Cancer Institute of Canada-Clinical Trials Group (NCIC-CTG)

Background: Temozolomide is an oral alkylating agent that crosses the blood-brain barrier, and has preclinical activity in breast cancer. This phase II trial sought to determine the activity and toxicity of temozolomide in metastatic breast cancer (MBC). Temozolomide was administered in a dose dense schedule of 150 mg/m(2) on days 1-7 and 15-21 in a 28-day cycle. Materials and methods: Patients had unidimensional disease for response assessment by RECIST criteria, up to two prior chemotherapy regimens for MBC, and may have had brain metastases if radiation was not expected to be required within 4 weeks. Results: Nineteen women were entered on the study. All were evaluable for toxicity and 18 were evaluable for response. The median age was 54 years; 14 had prior chemotherapy for MBC and 12 had prior hormones. Sites of disease included bone, brain, liver and lung. Treatment was well tolerated with 14/19 receiving > 90% planned dose intensity. Common grade 1-3 drug-related effects included nausea, fatigue, vomiting, anorexia and skin rash. Grade 3-4 hematologic toxicities included granulocytopenia and thrombocytopenia. Of the 18 evaluable patients, there were no objective responses; three had stable disease and 15 progressive disease. Conclusions: No responses to temozolomide were documented in these heavily pretreated women with extensive MBC including brain metastases.