SAN ANTONIO--Three different regimens of vinorelbine tartrate(Drug information on vinorelbine tartrate) (Navelbine) combined with established chemotherapeutic agents led to significant responses in up to 60% of patients with advanced or metastatic breast cancer, including previously treated patients.
In the largest of the three studies, 35 (56.4%) of 62 patients with metastatic breast cancer responded to the combination of vinorelbine and doxorubicin(Drug information on doxorubicin) as first-line chemotherapy. Seven patients had complete responses, and 28 had partial responses; an additional 16 patients remained stable, New York University oncologist Howard Hochster reported at a general session of the San Antonio Breast Cancer Symposium.
The dosing regimen consisted of 50 mg/m² of doxorubicin on day 1, and 25 mg/m² of vinorelbine on days 1 and 8. The regimen was repeated every 3 weeks for eight cycles, after which patients continued weekly vinorelbine until progression. The patients completed a median of six cycles, and 30% completed eight cycles, said Dr. Hochster, assistant professor of medical oncology/hematology.
The doxorubicin dose was reduced to 40 mg/m² for patients whose ANC was between 1,000 and 2,000, or whose platelet count was 75,000 to 100,000. If the ANC fell below 1,000, or platelets below 75,000, the day 1 doses of doxorubicin and vinorelbine were delayed for a week. The day 8 vinorelbine dose was delayed 1 week for grade 4 neutropenia, or if platelets fell below 75,000.
One-year survival for the cohort was 75%, and 44% of the patients have died. Median survival was 94 weeks, and median time to progression was 34 weeks.
Grade 4 granulocytopenia occurred in 87% of the patients but, in most cases, did not require intervention, Dr. Hochster said. Dose modifications mitigated problems with further episodes of granulocytopenia, which occurred in only 30% of all chemotherapy cycles. Eighteen patients required hospitalization for febrile neutropenia.
Thrombocytopenia, nausea, and vomiting were not significant problems. Three cases of grade 3 cardiotoxicity occurred, and one patient died of heart failure.