BREAST: METASTATIC: ER+, HER2 negative: 2nd Line: ESR1 mutant: SMX 18001

An Open-Label, Randomized, Multicenter Study Evaluating the Activity of Lasofoxifene Relative to Fulvestrant for the Treatment of Postmenopausal Women With Locally Advanced or Metastatic ER+/HER2− Breast Cancer With an ESR1 Mutation

Title
Sermonix SMX 18001 (ESR1 mutated breast)
Study Title

An Open-Label, Randomized, Multicenter Study Evaluating the Activity of Lasofoxifene Relative to Fulvestrant for the Treatment of Postmenopausal Women With Locally Advanced or Metastatic ER+/HER2− Breast Cancer With an ESR1 Mutation

Site Link
Malignancy
Breast cancer, invasive breast cancer, BC, hormone receptor positive BC
Stage
Disease Setting
Metastatic/Palliative
Line Of Therapy
2nd Line or later endocrine tx
Investigational Agent
Lasofoxifene
Drug Class
SERM
PI
Lee Schwartzberg, MD
Sponsor
Sermonix Pharmaceuticals LLC
Phase
Status
Key Eligibility Criteria
Key Eligibility Criteria Details
  • Postmenopausal women with locally advanced or metastatic breast cancer
  • Progression on an aromatase inhibitor (AI) in combination with a CDK4/6 inhibitor
  • Demonstrated prior sensitivity to endocrine therapy (recurrence or progression after at least 12 months of treatment in metastatic setting)
  • Measurable or non-measurable disease allowed
  • One of the following ESR point mutations in cell-free DNA:
    • Y537S, Y537C, D538G, E380Q, S463P, V534E, P535H, L536H, L536P, L536R, L536Q, or Y537N
  • May have received up to one chemothearpy regimen in adjuvant or neoadjuvant setting
  • ECOG PS 0-1
  • No prior use of any SERM with following exception
    • OK if tamoxifen previously used in adjuvant setting with relapse at least 1 year after stopping tamoxifen
  • No prior everolimus or PI3K inhibitors
  • No presence of CNS disease
  • No immediate need for chemotherapy
  • No HIV, HBV, HCV
  • No prior malignancy in last 5 years except non-melanoma skin cancer or early stage cervical cancer
  • No uncontrolled HTN
  •  
Objective
  • Primary- PFS
  • Secondary- CBR, ORR, Safety
Assessment Frequency
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Assessment Frequency 2
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Assessment Frequency Link
Path
ER positive, HER2 negative
Dosing Frequency
Control Agents
Fulvestrant
Study Protocol
Randomized
Yes
X