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NCT Number: NCT06966700

A Clinical Study of Sacituzumab Tirumotecan (Sac-TMT, MK-2870) in People With Breast Cancer (MK-2870-032)

Researchers are looking for new ways to treat types of breast cancer that are both:

* High-risk, which means the cancer may have a higher chance of getting worse or coming back after treatment * Early-stage, which means the cancer is in the breast or the lymph nodes around the breast The 2 types of breast cancer in this study are triple-negative breast cancer (TNBC) and hormone receptor (HR)-low positive/human epidermal growth factor receptor-2 (HER2) negative breast cancer. These cancers have zero or a low amount of a protein called HER2 and other proteins that attach to the hormones estrogen or progesterone.

Sacituzumab tirumotecan (also known as sac-TMT or MK-2870), the study medicine, is a type of targeted therapy. A targeted therapy is a treatment that works to control how specific types of cancer cells grow and spread.

The main goals of this study are to learn if people who receive sac-TMT, pembrolizumab, and chemotherapy:

* Have fewer cancer cells found in the tumors and lymph nodes removed during surgery compared to those who receive only pembrolizumab and chemotherapy * Live longer without the cancer growing, spreading, or coming back compared to people who receive only pembrolizumab with chemotherapy

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Key information

Conditions

Breast Neoplasms Breast Diseases HR Low-Positive/HER2-Negative Breast Neoplasms Neoplasms Neoplasms by Site Parkinson Disease 4, Autosomal Dominant Lewy Body Skin Diseases Skin and Connective Tissue Diseases Triple Negative Breast Neoplasms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Instituto de Investigaciones Clinicas Mar del Plata ( Site 6008), Mar del Plata, Buenos Aires, Argentina

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

The main inclusion criteria include but are not limited to the following:

  • Has previously untreated high-risk, early-stage, non-metastatic (M0) breast cancer (BC), defined as any of the following combined primary tumor (T) and regional lymph node (N) staging per AJCC 8th edition criteria as assessed by the physician investigator based on radiological and/or clinical assessment:
  • cT1c, N1-N2
  • cT2, N0-N2
  • cT3, N0-N2
  • cT4a-d, N0-N2
  • The participant must have a centrally confirmed diagnosis of BC that is triple-negative or HR-low+/HER2- (defined as estrogen receptor (ER)-low+ expression in 1% to 10% cells and HER2- as by the most recent American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines.
  • Provides a core needle biopsy from the primary breast tumor at screening to the central laboratory.
  • Has Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 performed within 28 days before Cycle1 Day 1 (C1D1).
  • Demonstrates adequate organ function.

Exclusion criteria

The main exclusion criteria include but are not limited to the following:

  • Metastatic (Stage IV) breast cancer or clinical node stage 3 (cN3) nodal involvement
  • Has received any prior treatment, including radiation, systemic therapy,and/or definitive surgery for currently diagnosed breast cancer
  • Has undergone excisional biopsy of the primary tumor, axillary lymph node dissection, and/or axillary sentinel lymph node biopsy prior to study treatment.
  • Received prior systemic anticancer therapy including investigational agents within 4 weeks before C1D1.
  • Received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent, or with an agent directed to another stimulatory or coinhibitory T-cell receptor (eg, CTLA-4, OX- 40, CD137).
  • Received prior treatment with a TROP2-targeted antibody-drug conjugate (ADC).
  • Received prior treatment with a topoisomerase I inhibitor-containing ADC.
  • Received a live or live-attenuated vaccine within 30 days before the first dose of study intervention.
  • Known additional malignancy that is progressing or has required active treatment within the past 5 years.
  • Uncontrolled systemic disease.
  • History of (noninfectious) pneumonitis/interstitial lung disease that required steroids, has current pneumonitis/interstitial lung disease or has suspected interstitial lung disease (ILD) or pneumonitis that cannot be ruled out by standard diagnostic assessments at Screening..

Treatment and study plan

Sacituzumab tirumotecan

Biological

IV infusion

Other names: Sac-TMT, MK-2870

Pembrolizumab

Biological

IV infusion

Other names: MK-3475, Keytruda®

Rescue medication

Drug

Participants receive rescue medication at the investigators discretion, per approved product label. Recommended rescue medications are histamine -1 (H1) receptor agonist, histamine-2 (H2) receptor antagonist, acetaminophen or equivalent, dexamethasone or equivalent infusion, or steroid mouthwash (dexamethasone or equivalent).

carboplatin

Drug

IV infusion

Other names: Paraplatin

paclitaxel

Drug

IV infusion

Other names: Taxol, Onxol

Doxorubicin

Drug

IV infusion

Other names: ADRIAMYCIN®

Epirubicin

Drug

IV infusion

Other names: Ellence®

Cyclophosphamide

Drug

IV infusion

Other names: Cytophosphane

Capecitabine

Drug

Oral tablet

Other names: Xeloda®

Olaparib

Drug

Oral tablet

Other names: LYNPARZA®

Primary outcomes

  1. Percentage of Participants with Pathological Complete Response (pCR) at the Time of Definitive Surgery

    Time frame: Up to approximately 30 weeks

    pCR (ypT0/Tis ypN0) is defined as the absence of residual invasive cancer on hematoxylin and eosin evaluation of the complete resected breast specimen and all sampled regional lymph nodes after completion of neoadjuvant systemic therapy per current American Joint Committee on Cancer (AJCC) staging criteria assessed by the local pathologist at the time of definitive surgery.

  2. Event-Free Survival (EFS)

    Time frame: Up to approximately 92 months

    EFS is defined as the time from randomization to disease progression that precludes surgery, local or distant recurrence, or death due to any cause, whichever occurs first.

Secondary outcomes

  1. Overall Survival (OS)

    Time frame: Up to approximately 115 months

    OS is defined as the time from randomization to death due to any cause.

  2. Percentage of Participants with pCR with No Ductal Carcinoma in Situ (pCR-no DCIS) at the Time of Definitive Surgery

    Time frame: Up to approximately 30 weeks

    pCR-no ductal carcinoma in situ (DCIS) (ypT0 ypN0) is defined as the absence of residual invasive and in situ cancer on hematoxylin and eosin evaluation of the complete resected breast specimen and all sampled regional lymph nodes after completion of neoadjuvant systemic therapy per current AJCC staging criteria assessed by the local pathologist at the time of definitive surgery.

  3. Percentage of Participants with pCR at the Time of Definitive Surgery (High-risk, early-stage, TNBC subset)

    Time frame: Up to approximately 30 weeks

    pCR (ypT0/Tis ypN0) is defined as the absence of residual invasive cancer on hematoxylin and eosin evaluation of the complete resected breast specimen and all sampled regional lymph nodes after completion of neoadjuvant systemic therapy per current American Joint Committee on Cancer (AJCC) staging criteria assessed by the local pathologist at the time of definitive surgery. The pCR will be presented for the subset of participants who enrolled with high-risk, early-stage, TNBC.

  4. Event-Free Survival (EFS) (High-risk, early-stage, TNBC subset)

    Time frame: Up to approximately 92 months

    EFS is defined as the time from randomization to disease progression that precludes surgery, local or distant recurrence, or death due to any cause, whichever occurs first. The EFS will be presented for the subset of participants who enrolled with high-risk, early-stage, TNBC.

  5. Overall Survival (OS) (High-risk, early-stage, TNBC subset)

    Time frame: Up to approximately 115 months

    OS is defined as the time from randomization to death due to any cause.

  6. Distant Progression or Distant Recurrence-Free Survival (DPDRFS)

    Time frame: Up to approximately 92 months

    DPDRFS is defined as the time from randomization to first distant progression or distant recurrence event as assessed by investigator, or death due to any cause, whichever occurs first.

  7. Change from Baseline in European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) Global Health Status-Quality of Life Score

    Time frame: Baseline and up to approximately 3 years

    The EORTC-QLQ-C30 is a 30-item questionnaire developed to assess the QoL of cancer patients. Participant responses to Item 30 (""How would you rate your overall quality of life during the past week?") is scored on a 7-point scale (1=Very Poor to 7=Excellent). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher value indicates a better level of function. The change from baseline in EORTC QLQ-C30 Item 30 score will be reported.

  8. Change from Baseline in EORTC QLQ-C30 Physical Functioning Score

    Time frame: Baseline and up to approximately 3 years

    The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to questions about their physical functioning are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher score indicates a better level of physical functioning.

  9. Change from Baseline in EORTC QLQ-C30 Role Functioning Score

    Time frame: Baseline and up to approximately 3 years

    The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to questions about their role functioning are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher score indicates a better level of physical functioning.

  10. Change from Baseline in EORTC QLQ-C30 Fatigue Score

    Time frame: Baseline and up to approximately 3 years

    The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to questions about their fatigue are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A lower score indicates a better level of function.

  11. Change from Baseline in EORTC QLQ Breast Cancer 42 (BR42) Systemic Therapy Side Effects Score

    Time frame: Baseline and up to approximately 3 years

    The EORTC QLQ-BR42 is a 42-item questionnaire to assess the overall quality of life of breast cancer patients. Participant responses to questions about their systemic therapy side effects are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A lower score indicates a lower level of side effects.

  12. Number of Participants Who Experience One or More Adverse Events (AEs)

    Time frame: Up to approximately 67 weeks

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.

  13. Number of Participants Who Discontinue Study Treatment Due to an AE

    Time frame: Up to approximately 54 weeks

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.

Study contacts

Contact information is provided by the study sponsor or research team.

Toll Free Number

CONTACT

[email protected]

1-888-577-8839

Sponsors and collaborators

Lead sponsor

Merck Sharp & Dohme LLC

Industry

Registry information

Official study title

A Phase 3, Randomized, Open-label Study to Evaluate the Efficacy and Safety of Sac-TMT (Sacituzumab Tirumotecan, MK-2870) Followed by Carboplatin/Paclitaxel vs Chemotherapy, Both in Combination With Pembrolizumab as Neoadjuvant Therapy for High-Risk, Early-Stage, Triple-Negative Breast Cancer or Hormone Receptor-low Positive/Human Epidermal Growth Factor Receptor-2 Negative Breast Cancer

Important dates

Study start
2025
Primary completion
2033
Study completion
2034
First posted
May 13, 2025
Registry last updated
Jul 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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