Elacestrant ELEVATE Phase 2: Everolimus/Abemaciclib Combo Improves PFS, Including in Non-ESR1-Mutated Patients
SCIENCE

Elacestrant ELEVATE Phase 2: Everolimus/Abemaciclib Combo Improves PFS, Including in Non-ESR1-Mutated Patients

By Léa · · San Antonio Breast Cancer Symposium 2025 / ELEVATE Phase 2
KO | EN

A new ladder is forming in metastatic breast cancer treatment. Stemline·Menarini’s elacestrant (Orserdu) is the first oral selective estrogen receptor degrader (SERD), FDA-approved in 2023. As monotherapy in ER+/HER2- + ESR1-mutated metastatic breast cancer, it showed PFS improvement vs standard endocrine therapy in EMERALD phase 3.

The ELEVATE phase 2 trial is the next step. PFS improvement was reported in elacestrant + everolimus (mTOR inhibitor) or elacestrant + abemaciclib (CDK4/6 inhibitor) combinations. Updated data presented at San Antonio Breast Cancer Symposium December 2025. More striking: effect observed in patients without ESR1 mutation, suggesting expansion potential beyond the current FDA approval.

What Is a SERD

Selective Estrogen Receptor Degrader (SERD) is a core drug category for ER+ breast cancer treatment. Mechanism:

  1. Binds estrogen receptor (full antagonist)
  2. Induces receptor protein degradation (proteasome pathway)
  3. Complete ER signaling blockade → tumor growth suppression

Existing SERDs:

  • Fulvestrant (Faslodex): injectable, 1st generation. EMBRACE trial. Disadvantages: monthly 2× IM injection, absorption variability
  • Elacestrant (Orserdu): oral, 2nd generation. EMERALD phase 3. First oral SERD
  • Camizestrant (AstraZeneca): oral 2nd generation, SERENA-6 phase 3
  • Giredestrant (Roche): oral 2nd generation, persevERA in progress

SERD vs SERM (tamoxifen): SERMs are partial agonists with estrogen action in some tissues (uterus). SERDs are complete blockade + receptor degradation. SERDs are more powerful.

From EMERALD to ELEVATE

EMERALD (phase 3, 2022 release):

  • ER+/HER2- + post 1~2 endocrine therapy progression + prior CDK4/6i use
  • Elacestrant 400mg/day vs standard endocrine alone
  • ESR1-mutated patients PFS 5.5 months vs 1.9 months
  • PFS improvement in non-ESR1-mutated patients but smaller

ELEVATE (phase 2, 2025 release):

  • Elacestrant + everolimus or elacestrant + abemaciclib
  • Additional PFS improvement (vs single)
  • Effect in non-ESR1-mutated patients
  • Expansion potential beyond FDA approval

Significance of ESR1 Mutation

ESR1 codes estrogen receptor alpha (ER-α). About 40% of metastatic breast cancer patients develop ESR1 mutations. With mutation:

  • ER stays active without estrogen (ligand-independent activation)
  • Aromatase inhibitor (letrozole, anastrozole) resistance → don’t work
  • Fulvestrant partially works, elacestrant stronger

The non-ESR1-mutated patient effect in ELEVATE may involve other circuits (e.g., PI3K/AKT/mTOR pathway activation). Everolimus’s mTOR blockade synergizes by cutting this circuit too.

Clinical Significance for Postmenopausal Women

  • ER+ breast cancer most common post-menopause (70~80% of all breast cancer)
  • Recurrent·metastatic: clearer 2nd-line option ladder for patients progressing after 1st-line endocrine
  • Oral option: avoids monthly 2× IM injection burden of fulvestrant
  • Post CDK4/6i progression: clear next step for the most common clinical scenario

Side Effect Profile

Elacestrant:

  • Nausea (35%): usually mild
  • Fatigue (19%)
  • VMS (vasomotor symptoms): in some patients
  • Partial liver enzyme elevation
  • Few serious side effects

Combination (everolimus):

  • Stomatitis, fatigue, rash, hyperlipidemia added
  • Pneumonitis (rare but risky)

Combination (abemaciclib):

  • Diarrhea, neutropenia, fatigue
  • Some venous thrombosis risk

Korean Market Entry

Elacestrant approved by Korean MFDS 2024. Insurance coverage in process. Some coverage possible under specialty disease cost reimbursement for cancer indication. Insurance expansion for ELEVATE combination indication awaits additional clinical trial data.

Clinical Application Guide

ER+/HER2- metastatic breast cancer ladder (2026 standard):

  • 1st line: CDK4/6i (palbociclib, ribociclib, abemaciclib) + AI (aromatase inhibitor) or fulvestrant
  • Post CDK4/6i progression: ESR1 mutation testing → if mutated, elacestrant alone or combination
  • Next step: PI3K/AKT inhibitor (alpelisib, capivasertib + fulvestrant)
  • HER2-low or HER2-zero: T-DXd (trastuzumab deruxtecan)
  • Triple negative: different ladder

Natural Matrix (Concurrent)

Natural matrix during cancer treatment doesn’t replace standard care but supports:

  • Body weight·insulin circuit: metformin shows recurrence reduction signal in some ER+ breast cancer data
  • Exercise 150 min/week: 25% recurrence reduction data (observational)
  • Vitamin D: increased recurrence·mortality in deficient patients
  • Omega-3: chronic inflammation attenuation
  • Protein: muscle loss avoidance
  • Dietitian·psychologist·exercise therapist matrix

Core message: ELEVATE results give postmenopausal ER+/HER2- metastatic breast cancer patients a stronger option ladder. Oral + non-ESR1-mutated patient effect expands clinical value. Standard treatment + natural matrix + regular monitoring matrix application is central.

Source: San Antonio Breast Cancer Symposium 2025 / ELEVATE Phase 2