ClinicalTrials.gg
RecruitingNCT05816655Updated Mar 18, 2025

Comparison of Clinical Efficacy Between Letrozole + Ribociclib and Fulvestrant + Letrozole + Ribociclib in Hormone Receptor Positive, HER2 Negative Metastatic Breast Cancer

A Phase 2 interventional study of Fulvestrant plus AI plus ribociclib and AI plus ribociclib in Metastatic Breast Cancer, sponsored by Korea University Guro Hospital. Recruiting at 2 sites in Korea, Republic of. Open to female participants aged 19 Years to 80 Years. Per ClinicalTrials.gov, last updated 2025-03-18.

Sponsored by Korea University Guro Hospital · Phase 2, Interventional, and Treatment

From the registry’s dates

  • Started May 2023; still recruiting 3 years 5 months later.
Phase
Phase 2
Study type
Interventional
Enrollment
202
Allocation
Randomized
Ages
19 Years to 80 Years
Sex
Female
01

Where this study stands

Counted across the records on this site · 2026-11-12

Among 94 studies testing fulvestrant in Breast Neoplasms — 12 open to participants now, 22 under way, 5 of them phase 3. Fulvestrant · Breast Neoplasms.

Planned enrollment
24th of 93
202 · median 70
Started
2023
with 3 others
Phase 2
58 of 94
7 open now
Primary completion
2028-12
later than 16 of 21 live
Registered
89th of 94
by date

Among the 94 studies testing fulvestrant in Breast Neoplasms, this one is the 24th largest by planned enrollment of the 93 interventional ones that give a count, is one of 4 that started in 2023, is one of 58 in phase 2, reaches primary completion later than 16 of the 21 other live ones, and was the 89th registered.

Breast Neoplasms

14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.

Browse Breast Neoplasms studies →

Open to participants now

12 of the 94 studies testing fulvestrant in Breast Neoplasms are open now, in 7 countries. Recruiting first, the newest first:

6 more — sign in →

By country, each count listing its studies:

All 12 open studies →

About fulvestrant

Fulvestrant: first FDA approval 2002 (FASLODEX), first EMA approval 2004. What it is approved for, and how studies give it, is on its page →

Who these studies take

Of the 2,400 Breast Neoplasms studies recruiting now, 1,572 (66%) set no upper age limit and 591 (25%) stop at 75 or younger; 103 take children under 18; 214 take healthy volunteers.

This study: 19 Years to 80 Years · female · no healthy volunteers.

The full table on the hub →

This tab as a report to print or save as PDF → With an account.

Was this useful?
Watch this landscapeDownload CSVNarrow it in search →With an account: a weekly mail of what changed among 94 studies testing fulvestrant in Breast Neoplasms, or all of them as a file.
02

Study summary

Aromatase inhibitor (AI) + CDK4/6 inhibitor is settled down as the standard first line therapy for HR+/HER2- metastatic breast cancer and all three CDk4/6 inhibitors, palbociclib, ribociclib, and abemaciclib are currently available for same indications. However, there is no effective treatment strategy for patients who have progressed on AI+CDK4/6 inhibitor. In particular, the clinical efficacies of subsequent hormone therapy are lowered when ESR1 mutations, one of mechanisms of AI resistance occur. In the PADA-1 trial, when ESR1 mutations in ctDNA were detected in patients treated with AI+CDK4/6 inhibitor, AI was switched to fulvestrant even if disease progression was not confirmed clinically. As a result, the median PFS was prolonged by about 8 months in this switching group compared to the group in which AI was continued. The results of this study suggested that delaying the occurrence of ESR1 mutations and early response to them are necessary to increase the effectiveness of hormone therapy.

In SWOG S0226 study, fulvestrant + AI combination showed significant benefits in PFS and OS compared to AI monotherapy as the first line therapy. Based on these results, the NCCN guideline suggests fulvestrant + AI combination as one of the first line hormone therapy options. However, the clinical effect of AI + fulvestrant + CDK4/6 inhibitor has not been investigated yet. Therefore, the investigators are planning to compare the clinical efficacy of AI+ fulvestrant + CDK4/6 inhibitor and AI+CDK4/6 inhibitor, and to investigate if a triple combination regimen can delay the emergence of ESR1 mutations and modulate occurred ESR1 mutations.

03

Conditions studied

  • Metastatic Breast Cancer

Browse trials for

04

Who can participate

Ages eligible
19 Years to 80 Years
Sexes eligible
Female
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Female ≥ 19 years of age
  • confirmed unresectable, locally advanced or invasive breast cancer with hormone receptor positive/ negative
  • No previous history of systemic endocrine or chemotherapy for metastatic, advanced breast cancer.
  • If the patient has received AI as endocrine therapy, the treatment free interval (TFI) should be more than 12 months after the end of adjuvant endocrine therapy. If the patient has received tamoxifen for adjuvant endocrine therapy, TFI less than 12 months will be allowed.
  • PS 0-2
  • Patients should have measurable or evaluable lesion based on version 1.1
  • Patients should have adequate organ function:

    • (absolute neutrophil count) ≥ 1.5 × 109/L
    • ≥ 100 × 109/L
    • Serum ≥ 9.0 g/dL
    • ≤1.5
    • Serum creatinine ≤ 1.5 X
    • \& ALT \<2.5 X ULN, if patients have hepatic metastasis, ALT \& ALT \<5.0 X ULN is allowed
    • Total serum \<1.5 X ULN, if patients have hepatic metastasis, Total serum bilirubin \<3.0 X ULN is allowed.
  • In the case of , patients who can adhere to appropriate during the study period and for at least 6 months after the end of study treatment.
  • Patients who understand the contents of the clinical trial and are cooperative with the process of the clinical trial.

Exclusion criteria

Exclusion Criteria:

  • Patients with a history of previous treatment with a CDK4/6 inhibitor or other systemic treatment for advanced/ breast cancer
  • Patients who have received prior treatment with fulvestrant and any ER-directed therapy including SERDs (selective estrogen receptor degrader)
  • Patients who have disease recurrence on aromatase inhibitor treatment as endocrine therapy
  • Patients who have symptomatic or untreated central nervous system metastasis
  • Patients who have a history of cardiovascular disease or heart failure as following conditions; within at least 6 months of myocardial infarction, unstable angina, or uncontrolled arrhythmia.
  • Patients having visceral crisis which needs rapid tumor reduction
  • Patients who have a history of any other cancer (except nonmelanoma skin cancer, carcinoma in-situ of the cervix, well-differentiated thyroid cancer)
  • Patients unable to cooperate with periodic blood samples collection
  • Patients who have active , infection, immune-suppressive disease, or infection. In case of chronic HBV infection, HBV DNA should be negative. Patients with complete remission of HCV infection are allowed.
  • Pregnant or breast-feeding women
  • Patients who are considered to be unsuitable for this trial by investigators.
Terms in these criteria, in plain language(19)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Histologically or cytologically confirmed

The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).

Your pathology report is the document that shows this.

Metastases

Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.

HER2

HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.

In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.

Adjuvant and neoadjuvant

Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.

ECOG performance status

A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.

0
Fully active, no restrictions.
1
Limited in strenuous activity, but walking and able to do light work, such as housework or office work.
2
Walking and able to look after yourself, but unable to work; up and about more than half of waking hours.
3
Able to look after yourself only in part; in bed or a chair more than half of waking hours.
4
Unable to look after yourself at all; in bed or a chair all day.

Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.

RECIST

The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.

“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.

Absolute neutrophil count (ANC)

The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.

It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

Hemoglobin (Hb)

The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).

INR, PT and aPTT (clotting tests)

Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.

Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.

ULN (upper limit of normal)

The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.

“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.

ALT and AST (liver enzymes)

Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.

Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.

Bilirubin

A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.

Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.

Childbearing potential

Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).

Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Hepatitis B tests

Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.

Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.

Hepatitis C tests

Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.

After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
202 participants (estimated)

Study arms

  • Experimental
    Fulvestrant arm

    fulvestrant + AI + ribociclib

    Drug: Fulvestrant plus AI plus ribociclib

  • Active comparator
    Control arm

    AI + ribociclib

    Drug: AI plus ribociclib

Interventions

  • DrugFulvestrant plus AI plus ribociclib

    Drug pages: Fulvestrant · Ribociclib

    Fulvestrant + AI + ribociclib +/- GnRH agonist

  • DrugAI plus ribociclib

    Drug page: Ribociclib

    AI + ribociclib +/- GnRH agonist

06

What researchers measure

Primary outcomes

  1. 24 month- progression free survival rate

    To compare 24 month- progression free survival rate (PFS rate) of letrozole + ribociclib + fulvestrant to letrozole + ribociclib for HR+/HER2- metastatic breast cancer (MBC) as the 1st line endocrine therapy

    Time frame: the time from randomization until documented disease progression or death from any cause, whichever occurs first, assessed up to 24 months.

07

Study locations

2 of 2 sites recruiting
08

References and documents

Individual participant data

Plan to share: Undecided

No publications or documents are linked to this record.

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started May 2023 (actual). Primary completion is estimated for Dec 2028, 67 months after the start.

Of 1,070 non-industry phase 2 interventional studies under Breast Neoplasms, half reached primary completion within 56 months of starting (the median), counting those still running; a quarter within 34 and three quarters within 87. This study's planned 67 months is above that.

Counting every sponsor, half of 1,302 studies reached it within 51 months; a quarter within 30 and three quarters within 82.

How these figures are worked out, and which studies are left out of them.

Registered
Mar 22, 2023
First posted
Apr 18, 2023
StartActual
May 31, 2023
Primary completionEst.
Dec 31, 2028
CompletionEst.
Jun 30, 2029
Last update
Mar 18, 2025
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Mar 18, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05816655
Lead sponsor
Korea University Guro Hospital
Responsible party
Park, In Hae (Principal investigator, Clinical professor, Korea University Guro Hospital) — Principal investigator
First posted
Apr 18, 2023
Start date
May 31, 2023
Primary completion
Dec 31, 2028 (estimated)
Completion
Jun 30, 2029 (estimated)
Last update
Mar 18, 2025

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Interested in this study?

Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.

No contact was published for this record. The registry link below has the sponsor’s details.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Studies of the drugs tested here: Fulvestrant · Ribociclib

Start the discussion