Evaluation of Lasofoxifene Versus Fulvestrant in Advanced or Metastatic ER+/HER2- Breast Cancer With an ESR1 Mutation

Summary

This is an open label, randomized, multicenter study evaluating the activity of lasofoxifene relative to fulvestrant for the treatment of pre- and postmenopausal women with locally advanced or metastatic ER+/HER2- breast cancer with an acquired ESR1 mutation and who have disease progression on an aromatase inhibitor (AI) in combination with a cyclin dependent kinase (CDK) 4/6 inhibitor. The primary objective is to evaluate the progression free survival (PFS) of 5 mg lasofoxifene relative to fulvestrant for the treatment of pre- and postmenopausal women with locally advanced or metastatic estrogen receptor positive (ER+)/human epidermal growth factor 2 negative (HER2-) breast cancer with an estrogen receptor 1 (ESR1) mutation. The secondary objectives are to evaluate: 1. Clinical benefit rate (CBR) and Objective Response Rate (ORR) 2. Duration of response 3. Time to response 4. Overall Survival (OS) 5. Pharmacokinetics of lasofoxifene 6. Quality of life (QoL): Quality of Life (QoL): vaginal assessment scale (VAS) and vulvar assessment scale (VuAS) questionnaires 7. Safety of lasofoxifene 8. Response to various ESR1 mutation (Y537S, Y537C, D538G, E380Q, S463P, V534E, P535H, L536H, L536P, L536R, L536Q, or Y537N).

Timeline

Start

2019-09-20

Primary completion

2025-05-08

Completion

2025-05-08

Publications

• Goetz MP, Bagegni NA, Batist G, Brufsky A, Cristofanilli MA, Damodaran S, Daniel BR, Fleming GF, Gradishar WJ, Graff SL, Grosse Perdekamp MT, Hamilton E, Lavasani S, Moreno-Aspitia A, O'Connor T, Pluard TJ, Rugo HS, Sammons SL, Schwartzberg LS, Stover DG, Vidal GA, Wang G, Warner E, Yerushalmi R, Plourde PV, Portman DJ, Gal-Yam EN. Lasofoxifene versus fulvestrant for ER+/HER2- metastatic breast cancer with an ESR1 mutation: results from the randomized, phase II ELAINE 1 trial. Ann Oncol. 2023 Dec;34(12):1141-1151. doi: 10.1016/j.annonc.2023.09.3104.

Drugs

Indications