Efficacy of Metronomic Oral Vinorelbine, Cyclophosphamide, and Capecitabine vs Weekly Intravenous Paclitaxel in Patients With Estrogen Receptor–Positive, ERBB2-Negative Metastatic Breast Cancer
Authors: Munzone Elisabetta , Regan Meredith M. , Cinieri Saverio , Montagna Emilia , Orlando Laura , Shi Ruichao , Campadelli Enrico , Gianni Lorenzo , Palleschi Michela , Petrelli Fausto , Bengala Carmelo , Generali Daniele , Collovà Elena , Puglisi Fabio , Cretella Elisabetta , Zamagni Claudio , Chini Claudio , Ruepp Barbara , Loi Sherene , Colleoni Marco ,   International Breast Cancer Study Group (IBCSG), Di Leo Angelo , Stahel Rolf A , Aebi Stefan , Baas Paul , Gelber Richard D , McGregor Keith , Peters Solange , Popat Sanjay , Rosell Rafael , Hiltbrunner Anita , Achille Giuseppe , Carrer-Wagner Anne , Celotto Daniela , Comune Carmen , Gasca Adriana , Giacomelli Nino , Kammler Roswitha , Pfister Rita , Roschitzki Heidi , Ruggeri Monica , Rugiati Elizabeth , Schneider Mirjam , Schroeder Judith , Troesch Sandra , Bouzan Colleen , Farah Subrina , Sun Zhuoxin , Shaw Holly , Blacher Lynette , King Colleen , Mundy Leslie , Polizzi Dorene , Greco Monica , Scott Karolyn , Starkweather Robert , Ghisini Raffaella , Masetti Roberto , Amaducci Laura , De Giorgi Ugo , Pinotti Graziella , Donadio Michela , Goldhirsch Aron 
Published: July 2023

Importance

In spite of the effectiveness of endocrine therapy plus cyclin-dependent kinase (CDK) 4/6 inhibitors as the first-line treatment for estrogen receptor (ER)-positive, erb-b2 receptor tyrosine kinase 2 (ERBB2 [formerly HER2/neu])-negative (ER+/ERBB2−) metastatic breast cancer (MBC), patients eventually develop resistance, and eventually most will receive chemotherapy. The METEORA-II trial compared a metronomic all-oral treatment with intravenous (IV) chemotherapy.

Objective

To compare the efficacy of the oral vinorelbine plus cyclophosphamide plus capecitabine (VEX) regimen vs weekly IV paclitaxel among patients with ER+/ERBB2− MBC who are candidates for chemotherapy.

Design, Setting, and Participants

This phase 2 randomized clinical trial including 140 women 18 years and older (randomized 1:1) with ER+/ERBB2− MBC was carried out from September 13, 2017, to January 14, 2021 at 15 centers in Italy. Eligible patients could have received 1 prior line of chemotherapy for MBC and/or 2 lines of endocrine therapy (including CDK4/6 inhibitors).

Interventions

In 4-week cycles, patients received either metronomic oral VEX or weekly IV paclitaxel.

Main Outcomes and Measures

The primary end point was investigator-assessed time to treatment failure (TTF) defined as the interval between the date of randomization to the end of treatment (because of disease progression or lack of tolerability or because further trial treatment was declined). Secondary end points included progression-free survival (PFS), overall survival (OS), and disease control rate (complete or partial response or stable disease lasting for at least 24 weeks).

Results

In total, 133 patients received either VEX (n = 70) or paclitaxel (n = 63) in 4-weekly cycles. The median age was 61 (range, 30-80) years. The VEX treatment significantly prolonged TTF vs paclitaxel (hazard ratio [HR], 0.61; 95% CI, 0.42-0.88; P = .008), median TTF was 8.3 (95% CI, 5.6-11.1) months for VEX vs 5.7 (95% CI, 4.1-6.1) months for paclitaxel, and the 12-month TTF was 34.3% for VEX vs 8.6% for paclitaxel. The median PFS was 11.1 (95% CI, 8.3-13.8) months vs 6.9 (95% CI, 5.4-10.1) months favoring VEX (HR, 0.67; 95% CI, 0.46-0.96, P = .03). The 12-month PFS was 43.5% for VEX vs 21.9% for paclitaxel. No difference in OS was found. The TF event for 55.6% of patients was progression of disease; for 23% it was AEs. More patients assigned to VEX had at least 1 grade 3 or 4 targeted adverse event (VEX, 42.9%; 95% CI, 31.1%-55.3% vs paclitaxel, 28.6%; 95% CI, 17.9%-41.3%), but essentially no alopecia.

Conclusion and Relevance

This randomized clinical trial found significantly prolonged TTF and PFS for oral VEX but no improvement in OS compared with intravenous paclitaxel, despite increased but still manageable toxic effects. The VEX regimen may provide more prolonged disease control than weekly paclitaxel for ER+/ERBB2− MBC.

Trial Registration

ClinicalTrials.gov Identifier: NCT02954055