Feasibility Study of Nanoparticle Albumin-Bound-Paclitaxel and S-1 Followed by Epirubicin/Cyclophosphamide as Neoadjuvant Chemotherapy in Patients With Operable Breast Cancer: A Prospective Study

Background: The efficacy and safety of nanoparticle albumin-bound (nab)-paclitaxel combined with S-1 in patients with operable breast cancer is uncertain. We evaluated the feasibility of this combination followed by epirubicin/cyclophosphamide (EC) as neoadjuvant chemotherapy in such patients.

Patients and methods: This was an open-label, single-arm, phase II, single-institution prospective study of 4 cycles of nab-paclitaxel (260 mg/m²) administered intravenously on day 1 in combination with S-1 (65 mg/m² orally twice daily) on days 1 to 14 every 21 days followed by EC as neoadjuvant chemotherapy.

Results: Of 30 patients, 1 required a dose interruption for nab-paclitaxel combined with S-1; 4 required a dose reduction for nab-paclitaxel, 1 for S-1, and 4 for EC. Mean relative dose intensities of nab-paclitaxel, S-1, and EC were 98.0%, 99.3%, and 98.2%, respectively. Overall clinical response rate was 96.7%. In histological response, grade 3, pathological complete response (pCR; ypT0/is and ypN0) rate was 63.3% and grade 2b (near pCR) was 3.3%. pCR was observed in 57.1% of luminal B human epidermal growth factor receptor type 2 (HER2)-negative patients, 55.6% of luminal B HER2-positive patients, 100% of HER2-positive patients, and 57.1% of triple-negative breast cancer patients. Grade 3/4 neutropenia was observed in 1 patient during nab-paclitaxel combined with S-1 and in 7 during EC treatments. The most frequent nonhematological severe adverse events were grade 3 peripheral neuropathy in 2 patients and grade 3 arthralgia in 2 patients during nab-paclitaxel combined with S-1.

Conclusion: Tri-weekly nab-paclitaxel with S-1 followed by EC is effective and well tolerated as neoadjuvant chemotherapy in patients with operable breast cancer.