452 Osteoprotegerin (OPG) and osteopontin (OPN): their usefulness in monitoring the Anastrzole (AN) treated advanced breast cancer (ABC) patients bearing bone metastases

Abstract

Capecitabine, a tumor-activated oral fluoropyrimidine, and albumin-bound paclitaxel (ab-paclitaxel) have substantial single-agent activity in patients with metastatic breast cancer (MBC). Taxane and antimetabolite doublets have improved efficacy compared with single agents. This phase II open-label trial was designed to test the safety and efficacy of capecitabine and ab-paclitaxel in previously untreated MBC.Patients received capecitabine (825 mg/m2 orally twice daily, approximately 12 hours apart, on days 1 to 15) and ab-paclitaxel (125 mg/m2 intravenously on days 1 and 8 of each cycle with no premedication) every 3 weeks. The primary endpoint was overall objective response rate (ORR), with evaluation performed after every 2 cycles. Entry criteria included measurable MBC, human epidermal growth factor receptor 2 (HER2) negativity, Eastern Cooperative Oncology Group (ECOG) performance status 0-2, no previous chemotherapy for metastatic disease, and > 6 months since adjuvant fluoropyrimidine or paclitaxel treatment.Fifty patients received at least 1 dose of study drug, with 46 patients evaluable for efficacy evaluation. Three hundred seventy-four cycles of therapy were delivered. Eighty percent of patients completed 8 cycles. The ORR was 61% (complete response [CR], 4%; partial response [PR], 57%), and 7 patients had sustained (≥ 24 weeks) stable disease for a clinical benefit rate of 76.1%. The median progression-free survival (PFS) was 10.6 months, and the median overall survival was 19.9 months. The most common adverse events (AEs) that were ≥ grade 3 were pain, hand-foot syndrome, and neutropenia.The combination of weekly ab-paclitaxel plus daily capecitabine orally at these doses and scheduling was well tolerated and showed substantial efficacy.