Phase II trial of carboplatin and etoposide in metastatic breast cancer

Carboplatin and Oral Etoposide in the Treatment of Patients with Advanced Breast Cancer Refractory to Anthracyclines

Aims and Background

To determine the efficacy and toxicity of the carboplatin and oral etoposide combination in patients with advanced breast cancer previously treated with anthracyclines.

Methods

Twenty-seven patients were treated with a maximum of 6 cycles of carboplatin (300 mg/m2) and etoposide (200 mg/m2) every 4 weeks. Prior treatment with an anthracycline was given as adjuvant in 17 patients and as first line treatment for advanced disease in 10 patients.

Results

Only 12 (44 %) patients completed all 6 cycles of chemotherapy. The median administered dose of carboplatin was 72 mg/m2/week and of etoposide 143 mg/m2/week. Two (7.5 %) complete and 4 (15 %) partial responses were observed. Both complete responses occurred in patients who received only mitoxantrone-containing adjuvant treatment, and lasted for 36 and 92+ weeks. The main toxicities included anemia (56 %), leukopenia (56 %), nausea/vomiting (50 %) and alopecia (79 %).

Conclusions

The combination of carboplatin and oral etoposide is effective and should probably be considered as an alternative therapeutic option for patients with advanced breast cancer refractory to anthracyclines.

Platinum-based compounds for the treatment of metastatic breast cancer

The role of platinum-based compounds (PBCs) in the treatment of metastatic breast cancer (MBC) has been extensively studied. As single agents, high response rates have been observed in first-line therapy, while results in pretreated patients were discouraging. Regimens containing cisplatin/carboplatin together with taxanes showed the highest efficacy and safety as both first-line and second-line therapy. When administered with vinorelbine, the combination was also active and well tolerated in anthracycline- and taxane-pretreated patients. Combining PBCs with etoposide or nucleoside analogues showed moderate activity, yet high toxicity in the case of etoposide. The overall results for the combination with anthracyclines were disappointing. Addition of trastuzumab to PBC combinations showed remarkable activity and good tolerability in patients with HER2/neu overexpression. The use of cisplatin or carboplatin alongside novel targeted therapeutics for patients with triple-negative MBC seems promising and is being further evaluated. The use of PBCs against MBC requires careful patient selection and combination with the right chemotherapeutic agent.

Platinum-based chemotherapy in metastatic breast cancer: current status

Cisplatin and carboplatin are active in previously untreated patients with metastatic breast cancer (MBC) with mean response rates (RRs) of 50 and 32%, respectively. In pretreated patients the RR to cisplatin/carboplatin monotherapy declines markedly to <10%. Cisplatin and carboplatin have been combined with many other cytotoxics. In first-line setting high activity has been observed in combination with taxanes or vinorelbine (RRs consistently approximately 60%). It appears that these newer combinations are superior to older regimens with etoposide (RRs 30 to 50%) or 5-fluorouracil (RRs 40 to 60%). Cisplatin-/carboplatin-based regimens with infusional 5-FU and epirubicin/paclitaxel/vinorelbine achieve high RRs of around 60 to 80%. However these regimens are difficult to administer in all patients because they require central venous access for continuous 5-FU infusion. In pretreated MBC the combinations of cisplatin-taxane/vinorelbine/gemcitabine or carboplatin-docetaxel/vinorelbine yield RRs of 40 to 50%, which are higher than those achieved with platinum-etoposide/5-FU. In locally advanced disease cisplatin-based regimens achieve very high RRs (>80%). This would suggest that in chemotherapy-naïve patients platinum-based therapy might have an important role to play. Additionally the synergy demonstrated between platinum compounds, taxanes and herceptin, in preclinical and clinical studies is of immense importance and the results of the two ongoing Breast Cancer International Research Group randomized phase III studies are eagerly awaited. These studies may help clarify the role of platinum compounds in the treatment of metastatic and possibly early breast cancer.

Platinum compounds in the treatment of advanced breast cancer

Interest in platinum compounds for the treatment of breast cancer has been reawakened because of preclinical studies indicating synergy of platinum salts with the monoclonal antibody trastuzumab in human breast cancer cell lines that overexpress HER2/neu. Cisplatin, carboplatin, and iproplatin are not very active as single agents in patients with previously treated metastatic breast cancer (MBC). The activity of oxaliplatin has not been adequately tested in refractory MBC. On the other hand, cisplatin is very active as first-line chemotherapy, with response rates (RR) of 50%; carboplatin appears to be moderately active in patients without prior chemotherapy (RR around 30%). The clinical effectiveness of the other platinum compounds (iproplatin, oxaliplatin, and others) has not yet been fully tested as first-line chemotherapy. Platinum compounds have been extensively tested in combination with other antitumoral agents. Cisplatin combinations have been employed as neoadjuvant chemotherapy in women with locally advanced breast cancer. These combinations are very active, although the precise contribution of cisplatin to the overall activity is not known. Combinations with cisplatin have been investigated, essentially, as salvage therapy for patients with previously treated MBC. The combinations of cisplatin with older pharmacological agents (5-fluorouracil, etoposide) have moderate activity, while the combinations of cisplatin with the newer agents (vinorelbine, paclitaxel, docetaxel, gemcitabine) appear to be more active. The combinations of carboplatin with the classical agents (5-fluorouracil, etoposide) are poorly active in previously treated MBC; however, the combination of carboplatin with the taxanes (docetaxel, paclitaxel) is more active. Of greatest interest is the synergy between the platinum derivatives and the monoclonal antibody trastuzumab demonstrated in vitro in breast cancer cell lines overexpressing HER2/neu. Currently, several combinations of platinum compounds (either cisplatin or carboplatin) with docetaxel and trastuzumab are under clinical testing in patients with MBC who overexpress HER2/neu. The preliminary results are very promising, and these combinations will soon be tested in the adjuvant setting. Cisplatin, carboplatin, and perhaps, oxaliplatin appear to have some antitumor activity in MBC and can be combined safely with other agents that are active in this disease. However, the precise role that platinum compounds play in the treatment of breast cancer remains to be defined.

Phase II study of carboplatin and etoposide as salvage treatment for patients with metastatic breast cancer

A phase II study of carboplatin and etoposide as salvage polychemotherapy in metastatic, infiltrating breast carcinoma was carried out with 25 multiply pretreated patients. Six of 25 patients (24%) had a partial response that lasted an average of 3.5 months; of the six responders, four had undergone either four or five previous chemotherapeutic treatments. Eight of 25 patients (32%) had stable disease, and 11 (44%) manifested disease progression. The median survival from time of entry to the salvage protocol was 8 months. There were treatment responses in lung, chest wall, liver, and skeleton. The most common side effects were leukopenia (68% of 25 patients), thrombocytopenia (56%), anemia (40%), fever (28%), and weakness (16%). Carboplatin combined with etoposide may be an effective and tolerable salvage regimen in advanced breast cancer.

Phase II trial of tamoxifen, etoposide, mitoxantrone, and cisplatin in patients with metastatic breast carcinoma

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.

High-dose cyclophosphamide, carboplatin, and etoposide with autologous stem cell rescue in patients with breast cancer

This study was designed to establish the toxicity and response rates o observed with a combination of high-dose cyclophosphamide, carboplatin, and etoposide with stem cell rescue in patients with breast carcinoma. Eligibility criteria included metastatic or locally advanced breast carcinoma ; aged < or equal to 60 years; performance status Eastern Cooperative Oncology Group (ECOG) 0-1; and creatinine clearance > or equal to 65 ml/min. Chemotherapy consisted of cyclophosphamide 25 mg/kg i.v. X 4 days, etoposide 400 mg/m(2) i.v. X 4 days, and carboplatin 375 mg/m(2) X 4 days. Bone marrow or peripheral blood stem cells were reinfused 48 h after completion of chemotherapy. Seventeen patients were treated in this study. The major toxicity was gastrointestinal (grades I and II). Fevers associated with neutropenia were observed in all the patients, but no episodes of bacteremia were documented. Hematopoietic toxicities were acceptable. No toxic deaths were observed. Six patients had chemotherapy-sensitive disease at time of transplant, nine had refractory disease, and two were untested. A response rate of 62% with 18% complete response (CR) was achieved. Two patients are free of disease at +7 and +9 months after transplantation. The combination of high-dose cyclophosphamide, carboplatin, and etoposide is well tolerated with a response rate comparable to previously reported high-dose chemotherapy regimens. However, in a poor prognostic risk group, namely patients with chemoinsensitive disease, this therapeutic approach seems to be of no advantage over standard chemotherapy.

Phase II study of oral etoposide for patients with advanced breast cancer

BACKGROUND

The objective of this study was to define the activity and toxicity of etoposide for patients with previously treated metastatic breast cancer.

METHODS

Thirty patients with measurable metastatic breast cancer who progressed after prior chemotherapy, hormonal therapy, or both, either as adjuvant therapy or for metastatic disease, were enrolled. There were 26 patients evaluable for response and 30 evaluable for toxicity. Treatment consisted of oral etoposide at a dose of 50 mg/m2/day administered for 21 consecutive days. Doses were modified depending on toxicity. Patients were evaluable for response after at least one cycle of therapy.

RESULTS

One complete response and four partial responses were observed. The overall objective response rate was 19% (5/26). Six patients had stable disease. Toxicity consisted mainly of Grade 4 neutropenia for 24% and Grade 4 thrombocytopenia for 13% of patients. There was one death due to neutropenic sepsis.

CONCLUSION

Oral etoposide is an effective, easily administered outpatient regimen with minimal toxicities. Etoposide is effective for patients with pretreated metastatic breast cancer.

Dose intensive therapy with autologous blood stem cell transplantation in breast cancer

BACKGROUND

Breast cancer is the commonest form of cancer in Australian women. Although approximately 50% of women with breast cancer achieve long term survival by current management methods, recurrent or metastatic disease is generally incurable. In addition, women with Stage II disease with > 10 positive axillary lymph nodes and also women with locally advanced disease (Stage III) have a poor survival even with adjuvant therapy.

AIMS

To assess the toxicity and efficacy of high-dose chemotherapy with autologous peripheral blood stem cell (PBSC) transplantation in women with both metastatic and poor prognosis primary breast cancer.

METHODS

Twenty-eight women with either metastatic (15) or poor prognosis (13) primary breast cancer were enrolled in the study between November 1988 to January 1993. PBSC were harvested using high-dose cyclophosphamide (Cy) with or without granulocyte-colony stimulating factor (G-CSF) and a myeloablative regimen of Cy, melphalan and carboplatin (CMCp) was used in the transplantation phase.

RESULTS

Optimum numbers of stem cells were harvested in 85% of patients. The use of five G/m2 Cy plus G-CSF resulted in better PBSC yields and a significant reduction in haematologic morbidity when compared to mobilisation with Cy alone. Twenty-two women underwent 23 PBSC transplants (PBSCT). There have been two early deaths due to sepsis. The predominant morbidities observed following high dose chemotherapy and transplantation have been nausea, mucositis and diarrhoea. The median number of days to discharge following infusion of PBSC was 15 (range 11-21). At a median follow up time of 1.1 years (range 0 months-3.6 years), 8/22 (36%) evaluable patients remain alive and disease free while 14/22 (64%) have relapsed or progressed or died.

CONCLUSION

High-dose chemotherapy and autologous PBSCT is a potentially highly effective treatment of women with metastatic and poor prognosis primary breast cancer. Randomised studies are required to compare this form of therapy to more standard forms of treatment in breast cancer.