Abstract P1-14-01: Final results of NorBreast-231, a randomized phase II study evaluating weekly oral vinorelbine versus weekly paclitaxel as first-line chemotherapy in patients with advanced breast cancer
Authors: Aapro MS , Hegg R , Ruiz Borrego M , Staroslawska E , Morales S , Cinieri S , De Freitas Junior R , Garcia Estevez L , Szombara E , Hervieu H , Groc M , Villanova GR 
Published: May 2019

Background: Single-agent chemotherapy (CT) is the standard treatment option in endocrine receptor (ER)-positive advanced breast cancer (ABC) after failure of endocrine therapy (ET) or in patients (pts) without visceral crisis. Both weekly paclitaxel (WP) and oral vinorelbine (OV) are among the recommended treatment options in this setting. The aim of this study was to evaluate the efficacy and safety profiles of OV and WP in a face to face study.

Material and methods: Pts with ER-positive, HER2-negative ABC, with an age ≥18 years and with a documented locally recurrent or metastatic involvement previously untreated by CT were eligible. Pts were randomized to receive, as first-line CT, 3 weekly-cycles of either: ARM A: weekly OV, given as a 80 mg/m2 dose (following a first cycle at 60 mg/m2, dose escalation to 80 in the absence of grade 3 or 4 toxicity at cycle 1); ARM B: WP 80 mg/m2 per week. Primary endpoint was disease control rate (DCR). Pts were stratified according to prior taxane CT and visceral metastases.

Results: 131 pts have been treated (OV: 66, WP: 65). Baseline pts characteristics (Arms OV/WP): median age 58/61 years; median number of prior ET: 2/2; prior (neo) adjuvant CT 74/72%; prior anthracycline 67/62%; prior taxane: 41/42%; &gt;3 metastatic sites 42/48%; visceral metastases 79/79%. Median number of cycles (range): 6(1-55)/7(1-44); dose escalation of OV was performed in 75% of pts. Safety: most common non-hematological related G3/4 adverse events per pt were fatigue 8/2%, peripheral neuropathy 0/5%, nausea 3/0%, diarrhoea 3/2%, vomiting 3/0%, constipation 3/2%, alopecia (G2) 2/34%, no toxic deaths; febrile neutropenia was present in 2/0% of pts. Quality of life: over time, no major differences between both arms have been observed. Efficacy: DCR in the intent-to-treat population was [95%CI] 75.8 [63.6-85.5] /75.4 [63.1-85.2]%; overall response rate 20/40%; median progression-free survival: 5.5/6.4 months. Median overall survival was: OV 27.6/WP 22.3 months.

Conclusion: Both OV and WP reached similar DCR rates of 75%. Each regimen presented a specific tolerance profile, with, in particular, a lower incidence of alopecia and peripheral neuropathy with OV. OV and WP are valid first-line CT options for ER-positive/HER2-negative pts with ABC.

Citation Format: Aapro MS, Hegg R, Ruiz Borrego M, Staroslawska E, Morales S, Cinieri S, De Freitas Junior R, Garcia Estevez L, Szombara E, Hervieu H, Groc M, Villanova GR. Final results of NorBreast-231, a randomized phase II study evaluating weekly oral vinorelbine versus weekly paclitaxel as first-line chemotherapy in patients with advanced breast cancer [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 P1-14-01.