A Phase 3 Study of Abemaciclib Plus Lasofoxifene or Fulvestrant in People With Advanced Breast Cancer

Full Title

An Open Label, Randomized, Multicenter Study Comparing the Efficacy and Safety of the Combination of Lasofoxifene and Abemaciclib to the Combination of Fulvestrant and Abemaciclib for the Treatment of Pre- and Postmenopausal Women and Men with Locally Advanced or Metastatic ER+/HER2- Breast Cancer with an ESR1 Mutation

Purpose

Researchers want to learn if combining lasofoxifene and abemaciclib works well in people with advanced breast cancer. This treatment will be compared to the usual breast cancer treatment with fulvestrant and abemaciclib. The people in this study have breast cancer that is fueled by estrogen and does not have the HER2 protein. They also have a mutation (change or variant) in the ESR1 gene. Lasofoxifene targets the ESR1 gene mutation.

Lasofoxifene and fulvestrant are hormonal therapies that work by lowering the amount of estrogen. Abemaciclib blocks a protein that may slow or stop the growth of breast cancer cells.

If you join this study, you will be randomly assigned to one of these treatments:

• Lasofoxifene and abemaciclib
• Fulvestrant and abemaciclib

Who Can Join

To join this study, there are a few conditions. You must:

• Have estrogen receptor-positive HER2-negative breast cancer that is locally advanced or has spread.
• Have a mutation in the ESR1 gene.
• Not have had more than 1 prior regimen of chemotherapy for advanced breast cancer.
• Be well enough to walk and take care of yourself. You must be able to do activities such as office work or light housework.
• Be age 18 or older.

Contact

For more information and to see if you can join this study, please call Dr. Sherry Shen’s office at 646-888-5134.