Abstract P6-14-03: Randomized phase II study evaluating weekly oral vinorelbine versus weekly paclitaxel in estrogen receptor positive, HER2-negative patients with advanced breast cancer (NorBreast-231 trial)

Rationale: Quality of Life is of prime importance in Advanced Breast Cancer (ABC), a mostly non-curable disease. Both paclitaxel (P) and vinorelbine as single-agent chemotherapy (CT) are recommended treatment options in the management of ABC non-responsive to hormone therapy (HT) and with no visceral crisis. These agents are active with a good tolerance profile. The benefits and safety of oral vinorelbine (OV) and weekly P have however never been evaluated in a face to face trial. Methods : Main eligibility criteria included: age ≥18 years, documented locally recurrent or metastatic involvement previously untreated by CT, estrogen receptor positive disease previously treated by at least one HT, HER2-negative status, Karnofsky PS ≥70 and presence of at least one measurable lesion. Study treatment (until progression): Arm A, OV 80 mg/m 2 weekly (following a first cycle at 60 mg/m 2 and dose escalation to 80 in the absence of grade 3 or 4 toxicity); Arm B: paclitaxel 80 mg/m 2 weekly. One cycle was defined as three weeks of treatment. Patients were stratified according to prior taxane (yes/no) and visceral metastases (yes/no). Primary endpoint was disease control rate (DCR), defined as confirmed complete response/partial response/stable disease of a minimum duration of 6 weeks. Results: 131 pts have been randomized (OV 66; P 65). Baseline patient characteristics (Arms A/B): median age 58/61 years; median number of previous HT 2/2; prior (neo)adjuvant CT 74/72%; prior anthracycline 64/62%; prior taxane 39/42%; u003e3 metastatic sites 42/48%; visceral metastases 80/78%. Safety: the most common non-haematological related G3/4 adverse events (≥3% patients) were: fatigue 7.6/1.5%, peripheral neuropathy 0/4.6%, nausea 3/0%, diarrhoea 3/1.5%, vomiting 3/0%, constipation 3/1.5%; alopecia (G2) was present in 1.5/33.8%; no toxic deaths 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 was 20/40%; stable disease was 56/35% respectively. Treatment exposure, other efficacy / safety parameters and quality of life results will be presented during the meeting. Conclusion: Both OV and P reached similar DCR rates of 75%. As expected, each regimen presented a specific tolerance profile, with, in particular, a lower incidence of alopecia and peripheral neuropathy with OV. Citation Format: Aapro M, Ruiz Borrego M, Staroslawska E, Morales S, Cinieri S, De Freitas Junior R, Garcia Estevez L, Szombara E, Hervieu H, Groc M, Villanova G, Hegg R. Randomized phase II study evaluating weekly oral vinorelbine versus weekly paclitaxel in estrogen receptor positive, HER2-negative patients with advanced breast cancer (NorBreast-231 trial) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-14-03.