Dose-dense nab-paclitaxel (nanoparticle albumin-bound paclitaxel) in adjuvant chemotherapy for breast cancer: A feasibility study

594 Background: We sought to evaluate the feasibility of substituting nab-paclitaxel (ABI-007) for paclitaxel as part of “dose-dense” adjuvant sequential doxorubicin / cyclophosphamide (AC) followed by taxane chemotherapy. Patients and Methods: Eligible patients had stage I-III breast cancer receiving adjuvant/neoadjuvant chemotherapy, ANC > 1500, and LVEF > 50%. Patients received AC (60 mg/m2 and 600 mg/m2) every 2 weeks × 4 cycles with G-CSF support, followed by nab- paclitaxel 260 mg/m2 every 2 weeks × 4 cycles. The endpoint was incidence of treatment delay during nab-paclitaxel therapy. Results: 66 women (median age 48 years) were enrolled. Among the first 11 given nab-paclitaxel without G-CSF support, one developed febrile neutropenia, and 4 had nab-paclitaxel treatment delays related to neutropenia (ANC < 1,000). The protocol was amended to require G-CSF support (filgrastim or pegfilgrastim) during nab-paclitaxel. Among the next 55 patients, 3 had febrile neutropenia, none during nab- paclitaxel. In cycles 6–8, nab-paclitaxel was delayed only 6 times (1 neutropenia, 3 hepatic toxicity, 2 patient scheduling); 96% of these cycles were delivered on time. By comparison, 82% of such cycles were delivered on time in a prior institutional study using paclitaxel. In the full cohort, 8 patients had nab-paclitaxel dose reduction, 4 for neuropathy, while other neuropathy was moderate (grade 2, n = 6; grade 3, n=1; grade 4, n=0). Conclusions: Administration of nab-paclitaxel every 2 weeks is feasible but requires G-CSF support. Data comparing nab-paclitaxel dose-delivery, toxicities and quality of life to paclitaxel as seen in prior studies will be presented. No significant financial relationships to disclose.