Background: Based on previous data demonstrating a potentially synergistic interaction between tamoxifen and cisplatin in metastatic melanoma therapy, a Phase II study was performed to assess the activity of tamoxifen, etoposide, mitoxantrone, and cisplatin (TEMP) in patients with metastatic breast carcinoma.
Methods: Forty-six patients with metastatic breast carcinoma were treated with tamoxifen, 10 mg orally, twice a day for 28 days; etoposide, 100 mg/m2, on Days 1-3; mitoxantrone, 10 mg/m2, on Day 1; and cisplatin, 30 mg/m2, on Days 1 and 2. Forty-four patients (7 with bone only disease) were evaluable for response and toxicity after at least 1 cycle of therapy. All patients had previously received doxorubicin-containing regimens in either the adjuvant or metastatic setting.
Results: The overall objective response rate for the 37 patients with visceral and/ or soft tissue disease was 41% (95% confidence interval, 25-58%). The objective response rate among women previously treated with doxorubicin in the adjuvant setting was 56% (14 of 24). Only 1 of 13 patients with metastatic carcinoma who had failed doxorubicin responded. Five of seven patients with bone-only disease had subjective improvement of bone pain without worsening of bone scans. Approximately 59% of patients had Grade 3 or 4 neutropenia at some time in their therapy and 1 patient died of neuropenic sepsis. Logistic regression analysis (n = 37) revealed that response was not related to estrogen receptor (ER) status or to the presence of visceral metastases.
Conclusions: TEMP appears to be an active regimen for patients with either ER positive (tamoxifen-resistant) or ER negative metastatic breast carcinoma that progresses after adjuvant doxorubicin therapy. Moreover, among patients who developed metastatic disease either during or < 12 months after adjuvant doxorubicin therapy, TEMP had a higher response rate than would have been predicted from previous studies. Although the mechanism remains to be elucidated, these results suggest a potentially synergistic role for tamoxifen in etoposide/cisplatin-based chemotherapy of breast carcinoma.