Phase 3 Study of ER+/HER2− Breast Cancer with an ESR1 Mutation
Research type
Research Study
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
IRAS ID
1007796
Contact name
Kelvin Ho
Contact email
Sponsor organisation
Sermonix Pharmaceuticals, Inc
Eudract number
2023-503708-10
Clinicaltrials.gov Identifier
Research summary
Women with metastatic breast cancer most often have cancer that is responsive to hormonal treatment. Unfortunately, hormonal treatment eventually stops working for these women. One common cause is the development of mutations in the estrogen receptor of the tumor. In early studies lasofoxifene has helped to overcome the resistance produced by the mutations. The combination of lasofoxifene and abemaciclib was also shown to produce benefit that is greater than either drug alone. Lasofoxifene is a hormonal therapy that is not approved but is being studied in a large study to determine if the combination of lasofoxifene and abemaciclib can be better than the approved drugs, fulvestrant and abemaciclib in women with metastatic breast cancer that have developed a mutation of the estrogen receptor. Currently there are no approved drugs in Europe for the treatment of patients who develop an estrogen receptor mutation but both fulvestrant and abemaciclib are approved for the treatment of breast cancer.
The purpose of this study is to compare the effects of the research medicine, lasofoxifene, in combination with abemaciclib to fulvestrant in combination with abemaciclib to find out which is better for treating breast cancer with oestrogen receptor mutations.
The main endpoint of the study will be the time from the start of the study medication to the time the medication is no longer helping to treat the breast cancer.
The study will also be measuring the size of the tumor to determine if it changed on study medication. All patients will be followed until they die.
All patients enrolled in the study will be treated until disease progression or withdrawn for any reason. After discontinuation of the study medication, the patient will continue to be followed until they die. It is estimated that full recruitment into the study will occur within 18-24 months. It is also estimated that on average each patient will remain on study medication for about 5-12 months.REC name
South West - Central Bristol Research Ethics Committee
REC reference
23/SW/0102
Date of REC Opinion
23 Oct 2023
REC opinion
Further Information Favourable Opinion