Abstract P1-15-23: Higher efficacy of 2-week nab-paclitaxel compared to solvent-based paclitaxel in neoadjuvant chemotherapy of triple negative breast cancers
Authors: Wang J , Xie F , Zhang L , Chen R , Zhu Q , Yin Z , You S , Jiang C , Zha X 
Published: May 2019

Background: Weekly nab-paclitaxel (nP) has better efficacy and safety for breast cancer patients compared with solvent-based paclitaxel (sP), but the result seems to be compromised when to 3-week nP though more convenient. However, reports about the 2-week nP in early breast cancer (EBC) are few. The current study aims to investigate whether 2-week nP is more effective than 2-week sP when added to an epirubicin/cyclophosphamide containing Neoadjuvant Chemotherapy (NAC) in Chinese EBCs .

Methods: Patients included in current retrospective study must meet at least one of the following criteria: tumor size≥3cm; positive axillary lymph node; human epidermal growth factor receptor-2 (HER2) overexpression; triple negative breast cancer (TNBC, estrogen receptors (ER), progesterone receptors (PR), and HER2 negative); patients with willingness to receive breastconserving therapy. Based on expressive levels of ER, PR, HER2 and Ki-67, patients were divided into different subgroups. After dose dense EC (E, epirubicin 90 mg/m2; C, cyclophosphamide 600 mg/m2), patients were received either nP (260 mg/m2) q2w or sP (175 mg/m2) q2w, with or without herceptin (first time 8mg/kg and followed by 6mg/kg). The primary endpoint was the pathological complete response (pCR) rates (ypT0N0 and ypT0/isN0) and the second endpoint was the toxicity.

Results: Total 151 patients were recruited from August 2013 to October 2017. Of them, 77 patients received nP and 74 received sP. Baseline characteristics are similar that the mean age was 47.68/51.82 years (nP/sP) and tumor size was 41.23/39.77 mm (nP/sP). After treatment, the pCR rate of TNBC patients was significantly higher in the group receiving nP (6/11, 54.4%) compared to sP (2/16, 12.5%, p=0.0332). No difference of pCR rates was found between nP and sP groups regarding to the threshold (20%) of Ki-67. Only few or no patients in subgroups of Luminal A, Luminal B HER2+ and Ki-67 ≤ 20% experienced pCR. Although the pCR was observed in other subgroups, there was no significant difference between patients with nP and sP . The side effects included peripheral neuropathy, allergic reactions, bone marrow suppression, and the incidence of peripheral neuropathy in nP was significantly increased.

Table 1.pCR rates.  nP(n=77)sP(n=74)P valueLuminal AypT0N00/150/5/ ypT0/isN00/150/5/Luminal B HER2-ypT0N03/202/330.3685 ypT0/isN04/202/330.1836Luminal B HER2+ypT0N00/00/3/ ypT0/isN00/01/3/HER2+ypT0N02/30/20.4000 ypT0/isN02/30/20.4000TNBCypT0N06/112/160.0332 ypT0/isN06/112/160.0332Luminal B HER2+ aypT0N01/151/60.4805 ypT0/isN02/151/61.0000HER2+ aypT0N03/135/90.1870 ypT0/isN05/136/90.3870Ki-67≤20%ypT0N00/160/12/ ypT0/isN01/160/12/Ki-67&gt;20%ypT0N015/6110/620.2437 ypT0/isN019/6112/620.1320a, patients received EC-TH, other patients received EC-T.

Conclusions: The results suggested that nP (260 mg/m2, q2w) was associated with a better efficiency profile compared to sP (175 mg/m2, q2w) in NAC for TNBC. Meanwhile, nP also brings more peripheral neuropathy. As a result, nP (260 mg/m2, q2w) is also an NAC option for TNBC in China.

Citation Format: Wang J, Xie F, Zhang L, Chen R, Zhu Q, Yin Z, You S, Jiang C, Zha X. Higher efficacy of 2-week nab-paclitaxel compared to solvent-based paclitaxel in neoadjuvant chemotherapy of triple negative breast cancers [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-23.