RecruitingMetastatic Breast Cancer

Evaluation of Lasofoxifene Combined With Abemaciclib Compared With Fulvestrant Combined With Abemaciclib in Locally Advanced or Metastatic ER+/HER2- Breast Cancer With an ESR1 Mutation

Eligible age

18+ yrs

Accepts

All genders

Locations

20 states

Healthy volunteers

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About this study

The goal of this clinical trial is to assess the efficacy, safety and tolerability of the combination of lasofoxifene and abemaciclib compared to fulvestrant and abemaciclib for the treatment of pre- and postmenopausal women and men who have previously received ribociclib or palbociclib-based treatment and have 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 main question the study aims to answer is: • To compare the efficacy of the combination of lasofoxifene and abemaciclib with that of fulvestrant and abemaciclib Participants will receive either receive 5 mg/d of oral lasofoxifene plus oral abemaciclib 150 mg twice a day or the combination of fulvestrant 500 mg intramuscular (IM) on Days 1, 15, and 29 and then once monthly thereafter plus oral abemaciclib 150 mg twice a day.

Sponsor: LeonaBio

You may qualify if…

✓ 1. Pre- or postmenopausal women or men.
✓ 2. Locally advanced and/or metastatic ER+ breast cancer with radiological or clinical evidence of progression on an AI in combination with either palbociclib or ribociclib as their first hormonal treatment for metastatic disease.
✓ 3. Histological or cytological confirmation of ER+/HER2 - disease
✓ 4. No evidence of progression for at least 6 months on an AI/CDKi combination for advanced breast cancer.
✓ 5. At least 1 or more ESR1 point mutations in the ESR1 ligand binding domain as assessed in cell- free ctDNA obtained from a blood or breast cancer tissue.
✓ 6. Locally advanced or metastatic breast cancer with at least 1 measurable (according to RECIST 1.1) lesion with or without non-measurable lesions.
✓ 7. Subjects may have received 1 cytotoxic chemotherapy regimen in the metastatic disease setting prior to study entry, but must have recovered from chemotherapy acute toxicity excluding alopecia and Grade 2 peripheral neuropathy.
✓ 8. Eastern Cooperative Oncology Group (ECOG) performance score of 0 or 1

You may not qualify if…

✕ 1. Lymphangitic carcinomatosis involving the lung.
✕ 2. History of Grade 3 or Grade 4 interstitial lung disease (ILD) on previous therapy.
✕ 3. Visceral crisis in need of cytotoxic chemotherapy as assessed by the investigator.
✕ 4. Prior progression of disease on abemaciclib, fulvestrant, or other selective estrogen receptor degrader (SERD) therapy.
✕ 5. Subjects with a known hypersensitivity to fulvestrant or to any of the excipients
✕ 6. Radiotherapy within 30 days prior to Visit 0 (Day 1) except in case of localized radiotherapy for analgesic purposes or for lytic lesions at risk of fracture, which can then be completed within 7 days prior to Visit 0 (Day 1). Subjects must have recovered from radiotherapy toxicities prior to Visit 0 (Day 1).
✕ 7. Known RB1 mutations or deletions that in the opinion of the investigator confer resistance to CDK4/6i. (Screening for RB1 mutation is not required for entry.)
✕ 8. History of long QTc (Q-T interval corrected for heart rate) syndrome or a QTc of \>480 msec.