The efficacy and safety of endostar combined with taxane-based regimens for HER-2-negative metastatic breast cancer patients

The purpose of the present study was to prospectively evaluate the efficacy and safety of endostar, a recombinant product of endostatin, combined with taxane-based regimens for HER-2 negative metastatic breast cancer (MBC) patients. Women with ages between 18–70 years with histologically confirmed MBC documented as HER-2-negative were included. Endostar was administered at 7.5 mg/m(2), d1–14, q21d and was continued until progressive disease, unacceptable toxicity, consent withdrawal, or completion of 24 months of endostar, whichever came first. Taxane-based chemotherapy was continued until progressive disease, unacceptable toxicity, consent withdrawal, or up to 8 cycles. The primary endpoint was overall response rate (ORR). Fifty-seven patients were recruited. The ORRs for the whole population, first-, second-, and third-line therapy or beyond were 68.4%, 79.3%, 54.5%, and 16.7%, respectively. The median PFS was 10.8 (8.0–12.1) months, yet the median OS was still not attained. For the patients receiving first-, second-, and third-line therapy or beyond, median PFS was 11.9, 7.5, and 7.4 months, respectively (P=0.048). No significant difference in median PFS between hormonal receptor-positive and -negative patients was observed. The most common drug-related grade 3–4 hematologic toxicities were neutropenia (80.7%) and leukopenia (77.2%). Six (10.5%) patients experienced febrile neutropenia. The most frequent drug-related grade 3–4 non-hematologic toxicities were liver dysfunction (10.5%) and peripheral neurotoxicity (8.8%). No treatment-related deaths were reported. We conclude that Endostar combined with taxane-based regimens may be effective and safe for the treatment of HER-2-negative MBC. However, further investigations on its long-term efficacy and toxicity are warranted.