Vinorelbine and cisplatin in metastatic breast cancer patients previously treated with anthracyclines.

PURPOSE: To assess the antitumor efficacy and safety of a vinorelbine and cisplatin combination in patients with metastatic breast cancer previously treated with anthracyclines. PATIENTS AND METHODS: Fifty-three patients with assessable metastatic breast cancer with previous exposure to anthracyclines (adjuvant n = 6, palliative n = 47) were studied. Cisplatin 75 mg/m2 on day 1 was given followed by 25 mg/m2 vinorelbine (VNR) on days 1 + 8, in a five-min i.v. infusion. Courses were repeated every three weeks on an outpatient basis. Treatment continued until disease progression, excess toxicity or patient refusal. Patients were classified according to their response to anthracyclines: anthracycline refractory patients were patients who had never responded under an anthracycline regimen. Anthracycline resistant patients were either metastatic patients who progressed within four months of completing anthracycline-based chemotherapy or patients who progressed within six months of completion of an anthracycline adjuvant treatment. Patients who progressed four months after the end of an anthracycline regimen in metastatic setting or six months after the end of an anthracycline regimen in adjuvant setting were considered as patients previously treated with anthracyclines and were called 'relapsed'.
RESULTS: Four patients (8%) achieved a complete response (CR) and twenty-two patients (41%) achieved a partial response (PR) with an overall response rate (OR) of 49% (95% confidence interval (CI): 35-63). Stable disease (SD) was observed in five patients (9%), twenty-two patients had progressive disease (PD). Responses according to previous sensitivity to anthracycline were as follow: 5 refractory patients achieved a PR from 14 patients (36%). Seven of sixteen resistant patients responded (44%), six with PR and one with CR. Among 23 'relapsed' patients, 14 responses were observed (61%), with 3 CR and 11 PR. There was no statistical difference in RR among the three groups. The median duration of response for all patients was 7 months, the median time to progression (TTP) 5 months and median overall survival 12 months. All patients were assessed for toxicity. The main toxicity was neutropenia grade 3 and 4 in 49% of patients. Febrile neutropenia requiring hospitalization was uncommon (2 patients). There were no treatment related deaths. Despite potential overlapping neurologic toxicities of the two drugs, only eight patients (15%) developed neuropathy, which was, however, mild (grades 1 and 2).
CONCLUSIONS: This cisplatin VNR regimen is well tolerated and active in patients who failed anthracyclines. The response rate, TTP and survival data are encouraging and indicate that cisplatin VNR may have a place as second-line treatment alternative to taxanes or other less active regimens. If these results can be verified in multi-institution trials, this combination of drugs would merit investigation as first-line therapy in this patient population.