Background: This retrospective study evaluated the activity and toxicity profile of a regimen of vinorelbine and 5-fluorouracil with levofolinic acid, given to a large series of patients with recurrent or refractory metastatic breast cancer after first-line chemotherapy.
Patients and methods: Overall, 286 evaluable patients were included in the analysis. Two chemotherapy schedules were reviewed: a) the bolus regimen consisted of levofolinic acid 100 mg/m2 and 5-fluorouracil 375 mg/m2, both administered i.v. on days 1,2 and 3, plus vinorelbine 25 mg/m2 i.v. bolus on days 1 and 8 every 3 weeks; b) the infusional regimen of levofolinic acid 100 mg/m2 given as a 2-hour infusion, followed by 5-fluorouracil 400 mg/m2 i.v. bolus and by 5-fluorouracil 600 mg/m2 administered as 22-hour continuous venous infusion (c.v.i) for 2 days, plus vinorelbine i.v. bolus on days 1 and 8.
Results: Overall, twelve patients achieved a complete response (4%; 95%CL 2%-7%) and 115 patients showed a partial response (40%, 95%CL 34%-46%), for an overall response rate of 44% (95CL 39%-50%). Sixty-one patients had stable disease (21%) and 98 patients progressive disease (34%). The tumor growth control rate was 63% (95%CL 60%-71%). Patients with soft tissue metastases as the dominant disease showed the highest response rate (56%), followed by viscera (48%) and bone (33%). The difference in response rate between patients with dominant visceral disease versus those with dominant bone disease was statistically significant (p=0.038). Patients treated with the bolus schedule achieved a 40% overall response rate with a 5% complete response rate, while those who received the infusional regimen had a 48% overall response rate with a 5% complete response rate. This difference was not statistically significant (p=0.164). The overall median duration of objective responses was 8.3 months (range 4-14 months), median time to progression of the all series was 6.1 months (range 2-24 months) and the median overall survival was 14.6 months (range 3-32). There was a statistically significant difference in survival among responder and non-responder patients (p=0.0009).
Conclusion: The results of this large off-trial analysis confirmed the clinical activity and adverse-event profile reported in controlled clinical trials of the vinorelbine/ 5-fluorouracil with levofolinic acid regimen in clinical practice. This combination regimen was active with a low toxicity burden and, therefore, represents a good therapeutic choice for patients who require second-line chemotherapy.