FDA approves combo for ESR1-mutated breast cancer - Scorecard - MDSpire
Coming Soon: Introducing MDSpire News. Learn more
Conexiant’s news site is now MDSpire News. Learn more

FDA approves combo for ESR1-mutated breast cancer

In an exploratory subgroup analysis of patients with ESR1-mutated tumors, median progression-free survival was 11.1 months with the combination and 5.5 months with imlunestrant alone.

  • By

  • Kathryn Wighton

  • September 21, 2026

  • 2 min

Share

Clinical Scorecard: FDA approves combo for ESR1-mutated breast cancer

At a Glance

CategoryDetail
ConditionEstrogen receptor-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer
Key MechanismsCombination of imlunestrant and abemaciclib targeting ESR1 mutations
Target PopulationAdults with disease progression following at least 1 line of endocrine therapy
Care SettingOncology clinical practice

Key Highlights

  • FDA approved imlunestrant with abemaciclib for specific breast cancer patients
  • Guardant360 CDx assay authorized for detecting ESR1 mutations
  • Study included 874 adults with previously treated advanced breast cancer
  • Significant improvement in progression-free survival with combination therapy
  • Warnings for embryo-fetal toxicity associated with both drugs

Guideline-Based Recommendations

Diagnosis

  • Use Guardant360 CDx assay to detect ESR1 mutations

Management

  • Consider imlunestrant plus abemaciclib for patients with ESR1 mutations

Monitoring & Follow-up

  • Monitor for progression-free survival and response rates

Risks

  • Embryo-fetal toxicity, diarrhea, neutropenia, interstitial lung disease, hepatotoxicity, venous thromboembolism

Patient & Prescribing Data

Adults with ESR1-mutated advanced or metastatic breast cancer

Combination therapy shows improved progression-free survival in patients with ESR1 mutations

Clinical Best Practices

  • Utilize genetic testing for ESR1 mutations in treatment planning
  • Monitor patients for adverse effects associated with imlunestrant and abemaciclib

Related Resources & Content

Original Source(s)

FDA approves combo for ESR1-mutated breast cancer

  • by Kathryn Wighton

  • September 21, 2026

Related Content

TGMS-UNet: A dual-branch segmentation network for ultrasound endometrium based on sequence guidance and multi-scale feature correction

Cancer Screening Gaps Seen in Sexual, Gender Minority Groups

A large BRFSS analysis points to persistent screening disparities among sexual orientation and gender identity minority respondents, with particularly large gaps in some gender identity minority groups.

Differences in Cascade Genetic Testing Among Families With Hereditary Cancer Risk