Pembrolizumab Adjuvant in Patients With Early-stage Triple Negative Breast Cancer With Residual Disease After Neoadjuvant Pembrolizumab Plus Chemotherapy (PLANET)

March 17, 2026 updated by: The Netherlands Cancer Institute

PembroLizumab Adjuvant in Patients With Early-stage Triple NEgaTive Breast Cancer With Residual Disease After Neoadjuvant Pembrolizumab Plus Chemotherapy - the Multicenter, Randomized Phase III, Pragmatic PLANET Trial

The phase III, multicenter, pragmatic PLANET trial aims to evaluate the benefit and safety of pembrolizumab as an addition to standard of care adjuvant treatment (capecitabine or olaparib) in triple negative breast cancer (TNBC) patients with residual disease (non-pCR) after neoadjuvant chemotherapy and pembrolizumab. All study procedures resemble routine clinical practice as much as possible (i.e., pragmatic clinical trial). In addition to the randomized trial, a registry will be set up, in which patients who reach pCR (and therefore, do not receive adjuvant treatment) will be registered and followed.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
1000

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Robin van den Borg, MD
  • Phone Number: 1405 +31205129111
  • Email: planet@nki.nl

Study Contact Backup

  • Name: Annemiek van Ommen-Nijhof, MD, PhD
  • Phone Number: +31205129111
  • Email: a.nijhof@nki.nl

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Male or female, ≥18 years of age on day of signing informed consent

  2. Stage II or III TNBC prior to the start of neoadjuvant treatment

    1. Locally assessed stage II or III TNBC according to the primary tumor (T) and regional lymph node (N) staging as per the American Joint Committee on Cancer (AJCC) for breast cancer staging criteria version 8
    2. Locally assessed estrogen receptor (ER) and/or progesterone receptor (PR) expression <10% and HER2-negative according to the ASCO-CAP guideline1
  3. The patient has received neoadjuvant treatment with chemotherapy (containing at least anthracyclines and taxanes) and pembrolizumab, with a minimum of two 6-weekly (or four 3-weekly) cycles of pembrolizumab
  4. The patient underwent breast surgery ≤12 weeks prior to inclusion in the study
  5. The patient is scheduled to start standard of care adjuvant treatment with capecitabine or olaparib (pending reimbursement), based on non-pCR after neoadjuvant treatment, defined as RCB score >02
  6. World Health Organization (WHO) performance status 0-2

  7. Adequate organ function, as assessed ≤30 days prior to the screening:

    1. Absolute neutrophil count (ANC) ≥1,000/mm3 (1.0 x 10e9 /L)
    2. Platelets ≥50,000/mm3 (50 x 10e9 /L);
    3. Estimated creatinine clearance ≥ 30 mL/min as calculated using the method standard for the institution;
    4. Total serum bilirubin ≤1.5 x upper limit of normal (ULN) (≤3.0 x ULN if Gilbert's disease);
    5. Aspartate aminotransferase (AST) and alanine transaminase (ALT) ≤3 x ULN
  8. Participants of childbearing potential must be willing to use an adequate method of contraception for the course of the study through 6 months after the last dose of study medication
  9. Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures
  10. Willingness to provide written informed consent, according to the Good Clinical Practice (GCP) and national/local regulations

Exclusion Criteria:

  1. Contra-indications for any of the study drugs
  2. Other invasive malignancies, except when treated with curative intent without chemotherapy AND more than 5 years ago
  3. The presence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule
  4. Any other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the patient inappropriate for entry into this study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Standard of care
Patients randomized to the control arm of the trial will receive standard of care adjuvant treatment (capecitabine or, in case of BRCA germline mutation, olaparib (if reimbursed)).
Drug: Standard of care (capecitabine or olaparib)
Standard of care adjuvant treatment (capecitabine or olaparib)
Other Names:
  • Xeloda / Lynparza
Experimental: Standard of care plus pembrolizumab
Patients randomized to the investigational arm of the trial will receive standard of care adjuvant treatment (capecitabine or, in case of BRCA germline mutation, olaparib (if reimbursed)) plus pembrolizumab.
Drug: Standard of care plus pembrolizumab
Standard of care adjuvant treatment (capecitabine or olaparib) plus pembrolizumab
Other Names:
  • KEYTRUDA

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Invasive disease free survival (IDFS)
Time Frame: Up to 10 years after inclusion of the last patient
IDFS, defined as time since randomisation to local or distant breast cancer recurrence, second primary non-breast cancer or death due to any cause, whichever occurs first.
Up to 10 years after inclusion of the last patient

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Distant disease free survival (DDFS)
Time Frame: Up to 10 years after inclusion of the last patient
DDFS, defined as time from randomisation to distant recurrence or death due to any cause.
Up to 10 years after inclusion of the last patient
Overall survival (OS)
Time Frame: Up to 10 years after inclusion of the last patient
OS, defined as time from randomisation to death due to any cause.
Up to 10 years after inclusion of the last patient
Safety/adverse events of adjuvant pembrolizumab
Time Frame: Up to 28 days after inclusion of the last patient
Measured by adverse events (AEs), adverse events of special interest (AESIs) and serious adverse events (SAEs).
Up to 28 days after inclusion of the last patient
Health related quality of life (HRQoL) - EORTC Quality of Life Questionnaire (QLQ)-C30
Time Frame: Up to 1 year after inclusion of the last patient
The effect of adjuvant pembrolizumab on health-related quality of life (HRQoL), assessed via Quality of Life Questionnaire (QLQ)-C30. For functional and global HRQoL scales, higher scores represent a better level of functioning and are converted to a 0 to 100 scale. For symptom-oriented scales, a higher score represents more severe symptoms.
Up to 1 year after inclusion of the last patient
Health related quality of life (HRQoL) - EORTC Quality of Life Questionnaire (QLQ)-BR42
Time Frame: Up to 1 year after inclusion of the last patient
The effect of adjuvant pembrolizumab on health-related quality of life (HRQoL), assessed via Quality of Life Questionnaire (QLQ)-BR42. For functional and global HRQoL scales, higher scores represent a better level of functioning and are converted to a 0 to 100 scale. For symptom-oriented scales, a higher score represents more severe symptoms.
Up to 1 year after inclusion of the last patient
Health related quality of life (HRQoL) - EuroQol Health Utilities Index (EQ-5D)
Time Frame: Up to 1 year after inclusion of the last patient
The effect of adjuvant pembrolizumab on health-related quality of life (HRQoL), assessed via EuroQol Health Utilities Index (EQ-5D). Overall scores range from 0 to 1, with low scores representing a higher level of dysfunction and 1 as perfect health
Up to 1 year after inclusion of the last patient
Cost-utility measured per incremental cost-effectiveness ratio (ICER)
Time Frame: Up to 28 days after inclusion of the last patient
Cost-utility, based on the incremental cost-effectiveness ratio (ICER).
Up to 28 days after inclusion of the last patient
Efficacy of pembrolizumab according to tissue biomarkers
Time Frame: Up to 10 years after inclusion of the last patient
Efficacy of pembrolizumab according to tissue biomarkers (including but not limited to stromal tumor infiltrating lymphocytes (sTILs) and programmed death-ligand 1 (PD-L1 expression))
Up to 10 years after inclusion of the last patient

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
The Netherlands Cancer Institute

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
BOOG Study Center
Stichting Treatmeds
Zorgevaluatie en Gepast Gebruik (ZE&GG)
Integraal Kankercentrum Nederland (IKNL)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Gabe Sonke, MD, PhD, Netherlands Cancer Institute - Antoni van Leeuwenhoek
  • Principal Investigator: Marleen Kok, MD, PhD, Netherlands Cancer Institute - Antoni van Leeuwenhoek
  • Principal Investigator: Agnes Jager, MD, PhD, Erasmus MC Cancer Institute

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 1, 2032

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 1, 2036

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 17, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 17, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 20, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 20, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • M25PLN
  • 2025-524229-41-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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