ClinicalTrials.gg
Sign In
CompletedNCT03492918Updated Oct 13, 2026

Pembrolizumab and Paclitaxel in Hypermutated Breast Cancer

A Phase 2 interventional study of Pembrolizumab, paclitaxel in Breast Neoplasms, sponsored by Yonsei University. Completed at 1 site in South Korea. Open to female participants aged 19 Years and older. Per ClinicalTrials.gov, last updated 2026-10-13.

Sponsored by Yonsei University · Phase 2, Interventional, and Treatment

Updated Oct 13, 2026Now CompletedStart date moved+7 moreGo to Updates ↓
Phase
Phase 2
Study type
Interventional
Enrollment
52
Allocation
Not applicable
Ages
19 Years and older
Sex
Female
01

Where this study stands

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

Among 85 studies testing pembrolizumab in Breast Neoplasms — 22 open to participants now, 45 under way, 8 of them phase 3. pembrolizumab · Breast Neoplasms.

Enrollment
33rd of 85
52 · median 44
Started
2022
with 5 others
Phase 2
56 of 85
13 open now
Registered
38th of 85
by date

Among the 85 studies testing pembrolizumab in Breast Neoplasms, this one is the 33rd largest by enrollment, is one of 6 that started in 2022, is one of 56 in phase 2, and was the 38th 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

22 of the 85 studies testing pembrolizumab in Breast Neoplasms are open now, in 11 countries. Recruiting first, the newest first:

17 more — sign in →

By country, each count listing its studies:

United States11
Canada2
China2
France2
Belgium1
Germany1
Italy1
Japan1
Poland1
Puerto Rico1
Spain1

All 22 open studies →

About pembrolizumab

pembrolizumab: first FDA approval 2014 (KEYTRUDA), first EMA approval 2015. 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 and older · 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 85 studies testing pembrolizumab in Breast Neoplasms, or all of them as a file.
02

Study summary

Abbreviated Title: Pembrolizumab in hypermutated breast cancer Trial Phase: II Clinical Indication: Hormone receptor-positive metastatic breast cancer Trial Type: Interventional Type of control: None Route of administration: Intravenous Trial Blinding: None Treatment Groups: Pembrolizumab plus Paclitaxel Number of trial subjects: Approximately 200 patients will be prescreened with whole exome sequencing. Then 52 patients will be enrolled in the treatment phase.

Estimated enrollment period: 12 months Estimated duration of trial: The sponsor estimates that the trial will require approximately 48 months from the time the first subject signs the informed consent until the last subject's last visit.

Duration of Participation: 12 months Estimated average length of treatment per patient: 8 months

03

Conditions studied

  • Breast Neoplasms

Browse trials for

04

Who can participate

The criteria were revised on the registry on Oct 13, 2026. See what changed

Ages eligible
19 Years and older
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

  1. Female patients with or cytologically confirmed premenopausal or , hormone receptor-positive, stage IV breast cancer.

    *Definition of hormone receptor positivity: nuclear staining of tumor cells for ER or PR between 1% and 100% on immunochemical staining using a tumor sample (ASCO/CAP guideline 2020).

  2. Patients who have given written for this clinical study.
  3. Patients who have not received systemic cytotoxic chemotherapy in the setting. Hormone therapy and anti- targeted therapy are not limited; however, patients are excluded if an anti-HER2 agent and a cytotoxic chemotherapeutic agent were used together as therapy. (Patients who have received a PARP inhibitor are eligible for enrollment.)
  4. Patients over 19 years of age as of the date of written informed consent.

  5. Patients who meet the criteria for hypermutation based on whole-exome sequencing.

    *Criteria for hypermutation: the number of nonsynonymous mutations is initially set at 70 or more, and is adjusted to the value corresponding to the top 20% or higher through interim analysis performed for every 30 cases. That is, the standard may change approximately every 30 cases.

  6. Patients with a metastatic tumor that can be biopsied for whole-exome sequencing. of a breast or axillary lymph node tumor is also allowed for patients with local recurrence after surgery or with stage IV disease from diagnosis.
  7. Patients with one or more based on v1.1. Biopsied tissue is considered a measurable lesion if not resected.
  8. Patients whose disease progression has been confirmed since the most recent treatment (not applicable at the prescreening stage; i.e., tissue biopsy is possible while maintaining the existing treatment).
  9. Patients with an expected life span of 12 weeks or more.
  10. performance status of 0 to 1.

  11. Patients whose organ function eligibility test, conducted within 14 days prior to the start of treatment, meets the criteria summarized in Table 2 below.

    Table 2. Adequate Organ Function Laboratory Values

  12. In the case of women of , a negative pregnancy reaction confirmed by a urine or serum pregnancy test within 72 hours prior to the first administration of the study drug. If the urine test is positive or negative but difficult to confirm, a serum pregnancy test is required.
  13. For women of childbearing potential, willingness to use an appropriate method of as described in Appendix 3 by day 180 after the last dose of the drug.

Note: If abstinence is the subject's routine lifestyle and preferred method of contraception, that method is also permitted.

Exclusion criteria

Exclusion Criteria:

  1. Women of who have a positive urine pregnancy test within 72 hours prior to the first administration of the study drug (see criterion 7). If the urine test cannot be confirmed as negative, a serum pregnancy test must be performed. In this case, if the serum pregnancy test is positive, the subject must be excluded from the study.
  2. Has a history of prior treatment with agents targeting , anti-PD-L1, or anti-PD-L2, or other stimulatory or co-inhibitory T-cell receptors (e.g., CTLA-4, OX40, CD137).
  3. Has received prior systemic therapy, including the study drug, within 4 weeks before the first dose [for kinase inhibitors or other short half-life drugs, if a period of at least 5 half-lives has not elapsed before randomization]. However, enrollment is permitted even within 4 weeks if 5 half-lives have elapsed and the adverse effects of the prior systemic therapy have completely resolved.
  4. Has received prior radiation therapy within 2 weeks before the start of treatment. Subjects must have recovered from all radiation-related toxicity, must not require , and must not have developed radiation pneumonitis. A 1-week is permitted for palliative radiation (≤2 weeks of radiation therapy) for non-CNS disease.

  5. Has received a within 30 days before the first dose of the drug.

    -Note: Seasonal influenza vaccines are generally inactivated influenza virus vaccines and are therefore permitted for study participation. However, intranasal influenza vaccines (e.g., Flu-Mist®) are live attenuated vaccines and are not permitted for study participation.

  6. Is currently participating in a clinical trial, or has participated in a clinical trial of an investigational drug and received investigational treatment or used an investigational medical device within 4 weeks before the first dose of the investigational drug.

    -Note: Subjects currently participating in an observational study may be enrolled in this trial if 4 weeks have elapsed since the last study drug administration.

  7. Has been diagnosed with immunodeficiency, or is chronically receiving systemic steroid therapy (at a dose exceeding the equivalent of 10 mg prednisone daily) or any other form of therapy within 7 days before the first dose of the study drug.

  8. Has a known additional invasive that is progressing or has required active treatment within the past 2 years.

    - Note: Subjects with basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer, or carcinoma in situ of the cervix who have been treated with curative intent are not subject to this exclusion.

  9. Has active central nervous system (CNS) and/or carcinomatous meningitis; such subjects are excluded from the trial. Subjects previously treated for may participate if they are stable (no evidence of disease progression on imaging for at least 4 weeks before the first dose of the study drug and neurological symptoms have returned to baseline), have no new or enlarging brain metastases, and will not require steroids for at least 7 days before study treatment. Carcinomatous meningitis is excluded regardless of clinical stability.
  10. Has a history of to pembrolizumab or its .
  11. Has hypersensitivity (grade 2 or higher peripheral neuropathy) or a to paclitaxel or its excipients.
  12. Has an active disease that has required systemic treatment within the past 2 years (e.g., use of disease-modifying agents, corticosteroids, or immunosuppressive drugs); such subjects are excluded. Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment.
  13. Has cardiovascular disease (including unstable angina, myocardial infarction, stroke, and ) or uncontrolled hypertension (SBP > 140 mmHg or DBP > 90 mmHg despite medication), as judged by the investigator, that occurred within 24 weeks before study participation.
  14. Has active non-infectious pneumonitis or a history of non-infectious pneumonitis; such subjects are excluded.
  15. Has an active infection requiring systemic treatment; such subjects are excluded.
  16. Has a history of immunodeficiency virus ( 1/2 or HTLV-1 antibody).

  17. Has active (HBs antigen +) or (anti-HCV antibody +) on laboratory testing within 180 days before the first dose of the study drug.

    However, enrollment is permitted if the following are demonstrated within 60 days before the first dose of the study drug:

    • For HBs antigen +: enrollment is permitted if the subject is inactive without treatment (HBV DNA \< 20 IU/mL), or if the viral load is undetectable while on antiviral therapy (HBV DNA \< 20 IU/mL).
    • For anti-HCV antibody +: enrollment is permitted if an HCV RNA PCR test is performed and is negative. However, subjects who are anti-HCV antibody + and have not undergone HCV RNA PCR testing are not eligible for enrollment.
  18. Has current active tuberculosis.
  19. Has any condition, treatment, or laboratory abnormality that could confound the study results or interfere with the subject's participation for the entire duration of the study, or is, in the investigator's opinion, otherwise unsuitable for participation in the study.
  20. Has a psychiatric disorder or substance abuse disorder that would interfere with the requirements of the clinical study.
  21. Is a woman who is currently pregnant or breastfeeding, or a woman of childbearing potential who is unwilling to continuously use an effective method of from the time of the prescreening or screening visit through 180 days after the last dose of the study drug.
  22. Has received an allogeneic tissue/solid organ transplant.
Terms in these criteria, in plain language(29)

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.

Postmenopausal

Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

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.

Line of therapy

A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.

“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.

Biopsy and archival tissue

A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.

Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.

Measurable disease

The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.

The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.

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.

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.

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.

PD-1, PD-L1 and checkpoint inhibitors

PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.

PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

Washout period

A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.

Live vaccines

Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Cancer (malignancy)

Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.

Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.

Brain metastases

Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).

Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.

Hypersensitivity

An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.

Excipients

The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.

Contraindication

A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.

Autoimmune disease

A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.

Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

TIA (transient ischaemic attack)

A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.

Stroke symptoms need emergency care at once, even if they go away.

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.

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.

05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
52 participants (actual)

Study arms

  • Experimental
    Pembrolizumab + Paclitaxel

    Patients with hormone receptor-positive metastatic breast cancer identified as hypermutated (nonsynonymous mutations ≥ 70 per tumor) by whole exome sequencing receive pembrolizumab 200 mg as an intravenous infusion every 3 weeks (up to 35 cycles), in combination with paclitaxel 80 mg/m² administered as an intravenous infusion on Days 1, 8, and 15 of each 28-day cycle.

    Drug: Pembrolizumab, paclitaxel

Interventions

  • DrugPembrolizumab, paclitaxel

    Drug pages: Pembrolizumab · Paclitaxel

    Enrolled patients received pembrolizumab (200 mg every 3 weeks) plus paclitaxel (80 mg/m² on days 1, 8, and 15 of a 28-day cycle) until disease progression, unacceptable toxicity or withdrawal of consent. Pembrolizumab was administered up to 35 cycles if patient showed persistent clinical response. According to pre-specified dose modification guidelines, dose reduction of weekly paclitaxel was permitted for management of toxicities. Dose modification of pembrolizumab was not permitted.

    Also known as: Keytruda

06

What researchers measure

Primary outcomes

  1. Investigator-assessed objective response rate (ORR)

    ORR was defined as the proportion of patients showing a complete response (CR) or partial response (PR) over the total patient population.

    Time frame: Tumour assessment was performed at baseline and every 8 weeks (+/- 7 days) based on appropriate imaging studies, such as computed tomography (CT) scans or magnetic resonance imaging (MRI) scans until progressive disease based on RECIST criteria version 1

Secondary outcomes

  1. progression-free survival (PFS)

    PFS was calculated from the first date of paclitaxel and pembrolizumab administration to the date of disease progression confirmed by imaging studies or patients' death.

    Time frame: through study completion

  2. overall survival (OS)

    OS was defined from the start date of paclitaxel plus pembrolizumab administration to patients' death or to last follow-up date

    Time frame: through study completion

  3. duration of response (DoR)

    DoR was defined as the time from the first documentation of objective response (CR or PR) to radiographic disease progression or death from any cause

    Time frame: through study completion

  4. clinical benefit rate (CBR)

    CBR was defined as the proportion of patients with CR, PR or stable disease lasting ≥24 weeks

    Time frame: 24 weeks

  5. safety

    Safety was assessed based on National Cancer Institute - Common Terminology Criteria for Adverse Events version 5.0 (NCI-CTCAE v5.0)

    Time frame: through study completion

07

Study locations

1 site
  • Yonsei Cancer Center at Yonsei University Health System
    Seoul, 03722, South Korea
08

Timeline

1 registry update since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedDate before it movedWhere the date was before it movedSimilar 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

Ran from Mar 2022 to primary completion in Jun 2026, 50 months.

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 50 months is below that.

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

Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 13, 2026: start Apr 2022 → Mar 2022, primary completion Apr 2023 → Jun 2026 and completion May 2023 → Jun 2026.

Earlier changes are on the record history on ClinicalTrials.gov ↗

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

Registered
Apr 1, 2018
First posted
Apr 10, 2018
StartActual
Mar 31, 2022was Apr 2022
Primary completionActual
Jun 19, 2026was Apr 2023
CompletionActual
Jun 19, 2026was May 2023
Last update
Oct 13, 2026
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.
Status
Status unknown→Completed
changed Oct 13, 2026
Start date
Apr 2022→Mar 31, 2022 (actual)
Oct 13, 2026
Primary completion
Apr 2023→Jun 19, 2026 (actual)
Oct 13, 2026
Study completion
May 2023→Jun 19, 2026 (actual)
Oct 13, 2026
Enrollment
30 (estimated)→52 (actual)
Oct 13, 2026
Eligibility
Criteria largely rewritten (63 changes)
What changed in the criteria
Inclusion criteria
  • RemovedPre or postmenopausal women with stage IV hormone receptor-positive breast cancer by histological or cytological confirmation
  • RemovedBe willing and able to provide written informed consent/assent for the trial
  • RemovedProgression after 1 or more lines of any systemic therapy (endocrine, HER2-targeted or chemotherapy) in the metastatic setting
  • AddedFemale patients with histologically or cytologically confirmed premenopausal or postmenopausal, hormone receptor-positive, stage IV breast cancer.
  • Added*Definition of hormone receptor positivity: nuclear staining of tumor cells for ER or PR between 1% and 100% on immunochemical staining using a tumor sample (ASCO/CAP guideline 2020).
  • AddedPatients who have given written informed consent for this clinical study.
  • AddedPatients who have not received systemic cytotoxic chemotherapy in the metastatic setting. Hormone therapy and anti-HER2 targeted therapy are not limited; however, patients are excluded if an anti-HER2 agent and a cytotoxic chemotherapeutic agent were used together as first-line therapy. (Patients who have received a PARP inhibitor are eligible for enrollment.)
  • EditedBePatients over 19 years of age on dayas of signingthe date of written informed consent.
  • Removed70 or more nonsynonymous mutations per tumor by WES
  • RemovedSubject who has biopsy-accessible tumor for WES. Biopsy on breast tumor or axillary nodes is acceptable if locoregional recurrence after primary surgery occurs or de novo stage IV breast cancer is diagnosed
  • AddedPatients who meet the criteria for hypermutation based on whole-exome sequencing.
  • Added*Criteria for hypermutation: the number of nonsynonymous mutations is initially set at 70 or more, and is adjusted to the value corresponding to the top 20% or higher through interim analysis performed for every 30 cases. That is, the standard may change approximately every 30 cases.
  • AddedPatients with a metastatic tumor that can be biopsied for whole-exome sequencing. Biopsy of a breast or axillary lymph node tumor is also allowed for patients with local recurrence after surgery or with stage IV disease from diagnosis.
  • EditedHavePatients with one or more measurable diseaselesions based on RECIST 1v1.1. Biopsied tumor may be countedtissue is considered a measurable lesion if it is not excisedresected.
  • RemovedDocumented disease progression on the most recent therapy
  • RemovedLife expectancy of > 12 weeks
  • AddedPatients whose disease progression has been confirmed since the most recent treatment (not applicable at the prescreening stage; i.e., tissue biopsy is possible while maintaining the existing treatment).
  • AddedPatients with an expected life span of 12 weeks or more.
  • EditedHave aECOG performance status of 0 orto 1 on the ECOG Performance Scale.
  • RemovedDemonstrate adequate organ function as defined in Table 3, all screening labs should be performed within 10 days of treatment initiation.
  • AddedPatients whose organ function eligibility test, conducted within 14 days prior to the start of treatment, meets the criteria summarized in Table 2 below.
  • AddedTable 2. Adequate Organ Function Laboratory Values
  • EditedFemale subjectIn the case of women of childbearing potential should have, a negative pregnancy reaction confirmed by a urine or serum pregnancy test within 72 hours prior to receiving the first doseadministration of the study medicationdrug. If the urine test is positive or cannot be confirmed as negativenegative but difficult to confirm, a serum pregnancy test will beis required.
  • RemovedFemale subjects of childbearing potential (Section 5.5.2) must be willing to use an adequate method of contraception as outlined in Section 5.7.2 - Contraception, for the course of the study through 120 days after the last dose of study medication.
  • RemovedNote: Abstinence is acceptable if this is the usual lifestyle and preferred contraception for the subject.
  • AddedFor women of childbearing potential, willingness to use an appropriate method of contraception as described in Appendix 3 by day 180 after the last dose of the investigational drug.
  • AddedNote: If abstinence is the subject's routine lifestyle and preferred method of contraception, that method is also permitted.
Exclusion criteria
  • AddedWomen of childbearing potential who have a positive urine pregnancy test within 72 hours prior to the first administration of the study drug (see criterion 7). If the urine test cannot be confirmed as negative, a serum pregnancy test must be performed. In this case, if the serum pregnancy test is positive, the subject must be excluded from the study.
  • EditedHas receiveda history of prior therapytreatment with anagents targeting anti-PD-1, anti-PD-L1, or anti-PD-L2 agent, or other stimulatory or co-inhibitory T-cell receptors (e.g., CTLA-4, OX40, CD137).
  • AddedHas received prior systemic therapy, including the study drug, within 4 weeks before the first dose [for kinase inhibitors or other short half-life drugs, if a period of at least 5 half-lives has not elapsed before randomization]. However, enrollment is permitted even within 4 weeks if 5 half-lives have elapsed and the adverse effects of the prior systemic therapy have completely resolved.
  • AddedHas received prior radiation therapy within 2 weeks before the start of treatment. Subjects must have recovered from all radiation-related toxicity, must not require corticosteroids, and must not have developed radiation pneumonitis. A 1-week washout period is permitted for palliative radiation (≤2 weeks of radiation therapy) for non-CNS disease.
  • AddedHas received a live vaccine within 30 days before the first dose of the investigational drug.
  • EditedHas received a live vaccine within 30 days of planned start of study therapy. -Note: Seasonal influenza vaccines for injection are generally inactivated fluinfluenza virus vaccines and are allowed; howevertherefore permitted for study participation. However, intranasal influenza vaccines (e.g., Flu-Mist®) are live attenuated vaccines, and are not allowedpermitted for study participation.
  • EditedIs currently participating and receiving study therapyin a clinical trial, or has participated in a studyclinical trial of an investigational agentdrug and received study therapyinvestigational treatment or used an investigational medical device within 4 weeks ofbefore the first dose of treatmentthe investigational drug.
  • Added-Note: Subjects currently participating in an observational study may be enrolled in this trial if 4 weeks have elapsed since the last study drug administration.
  • EditedHas a diagnosis ofbeen diagnosed with immunodeficiency, or is chronically receiving systemic steroid therapy (at a dose exceeding the equivalent of 10 mg prednisone daily) or any other form of immunosuppressive therapy within 7 days prior tobefore the first dose of trial treatmentthe study drug.
  • RemovedHas a known history of active TB (Bacillus Tuberculosis)
  • AddedHas a known additional invasive malignancy that is progressing or has required active treatment within the past 2 years.
  • Added- Note: Subjects with basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer, or carcinoma in situ of the cervix who have been treated with curative intent are not subject to this exclusion.
  • EditedHas known active central nervous system (CNS) metastases and/or carcinomatous meningitis; such subjects are excluded from the trial. Subjects with previously treated for brain metastases may participate providedif they are stable (withoutno evidence of disease progression byon imaging for at least four4 weeks prior tobefore the first dose of trial treatmentthe study drug and any neurologicneurological symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and arewill not usingrequire steroids for at least 7 days prior to trialbefore study treatment. This exception does not include carcinomatousCarcinomatous meningitis which is excluded regardless of clinical stability.

…and 23 more changes, on the record history on ClinicalTrials.gov ↗

Oct 13, 2026
Interventions
Changed Pembrolizumab→Pembrolizumab, paclitaxel. Arms added: Pembrolizumab + Paclitaxel; arms removed: pembrolizumab group
Oct 13, 2026
Primary outcomes
1 edited
What changed in the outcomes
  • EditedChange ofInvestigator-assessed objective response rate (ORR) by RECIST 1.1Time frame: Every 3 cycles (each cycle is 21 days) → Tumour assessment was performed at baseline and every 8 weeks (+/- 7 days) based on appropriate imaging studies, such as computed tomography (CT) scans or magnetic resonance imaging (MRI) scans until progressive disease based on RECIST criteria version 1
Oct 13, 2026
Secondary outcomes
1 edited, 4 added
What changed in the outcomes
  • EditedClinicalclinical benefit rate (CBR) by RECIST 1.1Time frame: through study completion, an average of 1 year → 24 weeks
  • Addedprogression-free survival (PFS)Time frame: through study completion
  • Addedoverall survival (OS)Time frame: through study completion
  • Addedduration of response (DoR)Time frame: through study completion
  • AddedsafetyTime frame: through study completion
Oct 13, 2026
Title
Pembrolizumab in Combination With Paclitaxel in the Hormone Receptor-positive Metastatic Breast Cancer With High Tumor Mutational Burden Selected by Whole Exome Sequencing: Korean Cancer Study Group Trial (KCSG BR20-16)→Pembrolizumab and Paclitaxel in Hypermutated Breast Cancer
Oct 13, 2026
Show all 1 update
  1. Oct 13, 2026
    Status unknown→Completed
    Start date Apr 2022→Mar 31, 2022 (now actual)
    Primary completion Apr 2023→Jun 19, 2026 (now actual)
    Study completion May 2023→Jun 19, 2026 (now actual)
    Enrollment 30 (estimated)→52 (actual)
    Eligibility Criteria largely rewritten (63 changes)
    What changed in the criteria
    Inclusion criteria
    • RemovedPre or postmenopausal women with stage IV hormone receptor-positive breast cancer by histological or cytological confirmation
    • RemovedBe willing and able to provide written informed consent/assent for the trial
    • RemovedProgression after 1 or more lines of any systemic therapy (endocrine, HER2-targeted or chemotherapy) in the metastatic setting
    • AddedFemale patients with histologically or cytologically confirmed premenopausal or postmenopausal, hormone receptor-positive, stage IV breast cancer.
    • Added*Definition of hormone receptor positivity: nuclear staining of tumor cells for ER or PR between 1% and 100% on immunochemical staining using a tumor sample (ASCO/CAP guideline 2020).
    • AddedPatients who have given written informed consent for this clinical study.
    • AddedPatients who have not received systemic cytotoxic chemotherapy in the metastatic setting. Hormone therapy and anti-HER2 targeted therapy are not limited; however, patients are excluded if an anti-HER2 agent and a cytotoxic chemotherapeutic agent were used together as first-line therapy. (Patients who have received a PARP inhibitor are eligible for enrollment.)
    • EditedBePatients over 19 years of age on dayas of signingthe date of written informed consent.
    • Removed70 or more nonsynonymous mutations per tumor by WES
    • RemovedSubject who has biopsy-accessible tumor for WES. Biopsy on breast tumor or axillary nodes is acceptable if locoregional recurrence after primary surgery occurs or de novo stage IV breast cancer is diagnosed
    • AddedPatients who meet the criteria for hypermutation based on whole-exome sequencing.
    • Added*Criteria for hypermutation: the number of nonsynonymous mutations is initially set at 70 or more, and is adjusted to the value corresponding to the top 20% or higher through interim analysis performed for every 30 cases. That is, the standard may change approximately every 30 cases.
    • AddedPatients with a metastatic tumor that can be biopsied for whole-exome sequencing. Biopsy of a breast or axillary lymph node tumor is also allowed for patients with local recurrence after surgery or with stage IV disease from diagnosis.
    • EditedHavePatients with one or more measurable diseaselesions based on RECIST 1v1.1. Biopsied tumor may be countedtissue is considered a measurable lesion if it is not excisedresected.
    • RemovedDocumented disease progression on the most recent therapy
    • RemovedLife expectancy of > 12 weeks
    • AddedPatients whose disease progression has been confirmed since the most recent treatment (not applicable at the prescreening stage; i.e., tissue biopsy is possible while maintaining the existing treatment).
    • AddedPatients with an expected life span of 12 weeks or more.
    • EditedHave aECOG performance status of 0 orto 1 on the ECOG Performance Scale.
    • RemovedDemonstrate adequate organ function as defined in Table 3, all screening labs should be performed within 10 days of treatment initiation.
    • AddedPatients whose organ function eligibility test, conducted within 14 days prior to the start of treatment, meets the criteria summarized in Table 2 below.
    • AddedTable 2. Adequate Organ Function Laboratory Values
    • EditedFemale subjectIn the case of women of childbearing potential should have, a negative pregnancy reaction confirmed by a urine or serum pregnancy test within 72 hours prior to receiving the first doseadministration of the study medicationdrug. If the urine test is positive or cannot be confirmed as negativenegative but difficult to confirm, a serum pregnancy test will beis required.
    • RemovedFemale subjects of childbearing potential (Section 5.5.2) must be willing to use an adequate method of contraception as outlined in Section 5.7.2 - Contraception, for the course of the study through 120 days after the last dose of study medication.
    • RemovedNote: Abstinence is acceptable if this is the usual lifestyle and preferred contraception for the subject.
    • AddedFor women of childbearing potential, willingness to use an appropriate method of contraception as described in Appendix 3 by day 180 after the last dose of the investigational drug.
    • AddedNote: If abstinence is the subject's routine lifestyle and preferred method of contraception, that method is also permitted.
    Exclusion criteria
    • AddedWomen of childbearing potential who have a positive urine pregnancy test within 72 hours prior to the first administration of the study drug (see criterion 7). If the urine test cannot be confirmed as negative, a serum pregnancy test must be performed. In this case, if the serum pregnancy test is positive, the subject must be excluded from the study.
    • EditedHas receiveda history of prior therapytreatment with anagents targeting anti-PD-1, anti-PD-L1, or anti-PD-L2 agent, or other stimulatory or co-inhibitory T-cell receptors (e.g., CTLA-4, OX40, CD137).
    • AddedHas received prior systemic therapy, including the study drug, within 4 weeks before the first dose [for kinase inhibitors or other short half-life drugs, if a period of at least 5 half-lives has not elapsed before randomization]. However, enrollment is permitted even within 4 weeks if 5 half-lives have elapsed and the adverse effects of the prior systemic therapy have completely resolved.
    • AddedHas received prior radiation therapy within 2 weeks before the start of treatment. Subjects must have recovered from all radiation-related toxicity, must not require corticosteroids, and must not have developed radiation pneumonitis. A 1-week washout period is permitted for palliative radiation (≤2 weeks of radiation therapy) for non-CNS disease.
    • AddedHas received a live vaccine within 30 days before the first dose of the investigational drug.
    • EditedHas received a live vaccine within 30 days of planned start of study therapy. -Note: Seasonal influenza vaccines for injection are generally inactivated fluinfluenza virus vaccines and are allowed; howevertherefore permitted for study participation. However, intranasal influenza vaccines (e.g., Flu-Mist®) are live attenuated vaccines, and are not allowedpermitted for study participation.
    • EditedIs currently participating and receiving study therapyin a clinical trial, or has participated in a studyclinical trial of an investigational agentdrug and received study therapyinvestigational treatment or used an investigational medical device within 4 weeks ofbefore the first dose of treatmentthe investigational drug.
    • Added-Note: Subjects currently participating in an observational study may be enrolled in this trial if 4 weeks have elapsed since the last study drug administration.
    • EditedHas a diagnosis ofbeen diagnosed with immunodeficiency, or is chronically receiving systemic steroid therapy (at a dose exceeding the equivalent of 10 mg prednisone daily) or any other form of immunosuppressive therapy within 7 days prior tobefore the first dose of trial treatmentthe study drug.
    • RemovedHas a known history of active TB (Bacillus Tuberculosis)
    • AddedHas a known additional invasive malignancy that is progressing or has required active treatment within the past 2 years.
    • Added- Note: Subjects with basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer, or carcinoma in situ of the cervix who have been treated with curative intent are not subject to this exclusion.
    • EditedHas known active central nervous system (CNS) metastases and/or carcinomatous meningitis; such subjects are excluded from the trial. Subjects with previously treated for brain metastases may participate providedif they are stable (withoutno evidence of disease progression byon imaging for at least four4 weeks prior tobefore the first dose of trial treatmentthe study drug and any neurologicneurological symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and arewill not usingrequire steroids for at least 7 days prior to trialbefore study treatment. This exception does not include carcinomatousCarcinomatous meningitis which is excluded regardless of clinical stability.

    …and 23 more changes, on the record history on ClinicalTrials.gov ↗

    Primary outcomes 1 edited
    What changed in the outcomes
    • EditedChange ofInvestigator-assessed objective response rate (ORR) by RECIST 1.1Time frame: Every 3 cycles (each cycle is 21 days) → Tumour assessment was performed at baseline and every 8 weeks (+/- 7 days) based on appropriate imaging studies, such as computed tomography (CT) scans or magnetic resonance imaging (MRI) scans until progressive disease based on RECIST criteria version 1
    Secondary outcomes 1 edited, 4 added
    What changed in the outcomes
    • EditedClinicalclinical benefit rate (CBR) by RECIST 1.1Time frame: through study completion, an average of 1 year → 24 weeks
    • Addedprogression-free survival (PFS)Time frame: through study completion
    • Addedoverall survival (OS)Time frame: through study completion
    • Addedduration of response (DoR)Time frame: through study completion
    • AddedsafetyTime frame: through study completion
    Interventions Changed Pembrolizumab→Pembrolizumab, paclitaxel. Arms added: Pembrolizumab + Paclitaxel; arms removed: pembrolizumab group
    Title Pembrolizumab in Combination With Paclitaxel in the Hormone Receptor-positive Metastatic Breast Cancer With High Tumor Mutational Burden Selected by Whole Exome Sequencing: Korean Cancer Study Group Trial (KCSG BR20-16)→Pembrolizumab and Paclitaxel in Hypermutated Breast Cancer
    + 5 other changes: verification date, description, conditions, site details and index terms

From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗

09

Registry details

Key details

Study ID
NCT03492918
Lead sponsor
Yonsei University
Responsible party
Sponsor
First posted
Apr 10, 2018
Start date
Mar 31, 2022
Primary completion
Jun 19, 2026
Completion
Jun 19, 2026
Last update
Oct 13, 2026

Oversight

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

Not currently enrolling

This study is completed, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.

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: Pembrolizumab · Paclitaxel

Other studies in this condition

Breast Neoplasms →

Other studies from this sponsor

Yonsei University →

Start the discussion