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

NCT07486687 | Not Yet Recruiting Phase 3

• 2 other identifiers: M25PLN2025-524229-41-00
• Study Type: interventional
• Target: 1,000
• Locations: 0 countries
• Sites: N/A

Brief Summary

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.

Conditions

Triple Negative Breast Cancer (TNBC), Early Setting; Early Stage Triple-Negative Breast Carcinoma; Triple -Negative Breast Cancer; Breast Cancer Stage II; Breast Cancer Stage III

Keywords

Immunotherapy; Pembrolizumab; Triple negative breast cancer; Breast cancer; TNBC; Adjuvant

Outcome Measures

Primary Outcomes (1)

• Invasive disease free survival (IDFS)

  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 Outcomes (8)

• Distant disease free survival (DDFS)

  Up to 10 years after inclusion of the last patient

• Overall survival (OS)

  Up to 10 years after inclusion of the last patient

• Safety/adverse events of adjuvant pembrolizumab

  Up to 28 days after inclusion of the last patient

• Health related quality of life (HRQoL) - EORTC Quality of Life Questionnaire (QLQ)-C30

  Up to 1 year after inclusion of the last patient

• Health related quality of life (HRQoL) - EORTC Quality of Life Questionnaire (QLQ)-BR42

  Up to 1 year after inclusion of the last patient

Study Arms (2)

Standard of care

ACTIVE COMPARATOR

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 plus pembrolizumab

EXPERIMENTAL

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

Interventions

Standard of care plus pembrolizumab DRUG

Standard of care adjuvant treatment (capecitabine or olaparib) plus pembrolizumab

Also known as: KEYTRUDA

Standard of care plus pembrolizumab

Standard of care (capecitabine or olaparib) DRUG

Standard of care adjuvant treatment (capecitabine or olaparib)

Also known as: Xeloda / Lynparza

Standard of care

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male or female, ≥18 years of age on day of signing informed consent
• Stage II or III TNBC prior to the start of neoadjuvant treatment
• 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
• Locally assessed estrogen receptor (ER) and/or progesterone receptor (PR) expression \<10% and HER2-negative according to the ASCO-CAP guideline1
• 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
• 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
• World Health Organization (WHO) performance status 0-2
• Adequate organ function, as assessed ≤30 days prior to the screening:
• Absolute neutrophil count (ANC) ≥1,000/mm3 (1.0 x 10e9 /L)
• Platelets ≥50,000/mm3 (50 x 10e9 /L);
• Estimated creatinine clearance ≥ 30 mL/min as calculated using the method standard for the institution;
• Total serum bilirubin ≤1.5 x upper limit of normal (ULN) (≤3.0 x ULN if Gilbert's disease);
• Aspartate aminotransferase (AST) and alanine transaminase (ALT) ≤3 x ULN
• 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
• Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures

You may not qualify if:

• Contra-indications for any of the study drugs
• Other invasive malignancies, except when treated with curative intent without chemotherapy AND more than 5 years ago
• The presence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule
• 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

Sponsors & Collaborators

• The Netherlands Cancer Institute: lead
• BOOG Study Center: collaborator
• Stichting Treatmeds: collaborator
• Zorgevaluatie en Gepast Gebruik (ZE&GG): collaborator
• Integraal Kankercentrum Nederland (IKNL): collaborator

MeSH Terms

Conditions

Triple Negative Breast Neoplasms; Breast Neoplasms

Interventions

Standard of Care; pembrolizumab; Capecitabine; olaparib

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Intervention Hierarchy (Ancestors)

Quality Indicators, Health Care; Quality of Health Care; Health Services Administration; Health Care Quality, Access, and Evaluation; Deoxycytidine; Cytidine; Pyrimidine Nucleosides; Pyrimidines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Fluorouracil; Uracil; Pyrimidinones; Deoxyribonucleosides; Nucleosides; Nucleic Acids, Nucleotides, and Nucleosides

Study Officials

• 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

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Robin van den Borg, MD

CONTACT

+31205129111; planet@nki.nl

Annemiek van Ommen-Nijhof, MD, PhD

CONTACT

+31205129111; a.nijhof@nki.nl

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 17, 2025
• First Posted: March 20, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): April 1, 2032
• Study Completion (Estimated): April 1, 2036
• Last Updated: March 20, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share