A Phase 3 interventional study of Sacituzumab tirumotecan and Pembrolizumab in Breast Neoplasms, sponsored by Merck Sharp & Dohme LLC. Recruiting at 259 sites in 40 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-13.
Sponsored by Merck Sharp & Dohme LLC (part of Merck & Co., Inc) · Phase 3, Interventional, and Treatment
The purpose of this study is to compare sacituzumab tirumotecan as a single agent, and in combination with pembrolizumab, versus Treatment of Physician's Choice (TPC) in participants with hormone receptor positive/human epidermal growth factor receptor-2 negative (HR+/HER2-) unresectable locally advanced, or metastatic, breast cancer.
The primary hypotheses are that sacituzumab tirumotecan as a single agent and sacituzumab tirumotecan plus pembrolizumab are superior to TPC with respect to progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) by blinded independent central review (BICR) in all participants.
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
This study's planned enrollment of 1,200 is above the median of 72 across 10,896 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →Merck Sharp & Dohme LLC is the lead sponsor of 2,166 studies on the registry; 132 are open to participants now.
Of its 501 completed or terminated interventional studies of FDA-regulated products, 370 (74%) have results posted.
Counted across the registry records on this site, refreshed daily.
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.
Exclusion Criteria:
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.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
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.
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.
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.
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 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 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.
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.
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.
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.
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.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive 4 mg/kg of sacituzumab tirumotecan once every 2 weeks (Q2W) via intravenous (IV) infusion until progressive disease or discontinuation.
Drug: Sacituzumab tirumotecan
Participants receive 4 mg/kg of sacituzumab tirumotecan Q2W via IV infusion until progressive disease or discontinuation PLUS 400 mg of pembrolizumab once every 6 weeks (Q6W) via IV infusion for up to 18 administrations (up to \~2 years).
Drug: Sacituzumab tirumotecan · Biological: Pembrolizumab
At the physician's discretion, participants receive chemotherapy of 80 mg/m\^2 of paclitaxel once every week (Q1W) via IV infusion OR 90 mg/m\^2 of paclitaxel once every 4 weeks (Q4W) via IV infusion OR 100 mg/m\^2 of nab-paclitaxel Q4W via IV infusion OR 1000 mg/m\^2 of capecitabine every 3 weeks (Q3W) orally OR 50 mg/m\^2 of liposomal doxorubicin once every 4 weeks (Q4W) via IV infusion, until progressive disease or discontinuation.
Drug: Paclitaxel · Drug: Nab-paclitaxel · Drug: Capecitabine · Drug: Liposomal doxorubicin
IV infusion
Also known as: MK-2870
IV infusion
Also known as: MK-3475, KEYTRUDA®
IV infusion
Also known as: TAXOL®
IV infusion
Also known as: ABRAXANE®
oral tablet
Also known as: XELODA®
IV infusion
Also known as: DOXIL®
Progression-Free Survival (PFS) ( sacituzumab tirumotecan versus treatment of physician's choice [TPC]; pembrolizumab + sacituzumab tirumotecan versus TPC)
PFS is defined as the time from randomization to the first documented progressive disease (PD) or death due to any cause, whichever occurs first as assessed by Response Criteria in Solid Tumors Version 1.1 (RECIST 1.1). PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions is also considered PD. PFS as assessed by blinded independent central review (BICR) will be presented.
Time frame: Up to ~40 months
PFS (Sacituzumab tirumotecan + pembrolizumab versus TPC)
PFS is defined as the time from randomization to the first documented progressive disease (PD) or death due to any cause, whichever occurs first as assessed by Response Criteria in Solid Tumors Version 1.1 (RECIST 1.1). PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions is also considered PD. PFS as assessed by BICR in participants with programmed cell death ligand 1 (PD-L1) at combined positive score (CPS) ≥1 tumors will be presented.
Time frame: Up to ~40 months
Overall Survival (OS)
OS is defined as the time from randomization to death due to any cause.
Time frame: Up to ~95 months
Progression-Free Survival (PFS) (pembrolizumab + sacituzumab tirumotecan + versus sacituzumab tirumotecan)
PFS is defined as the time from randomization to the first documented progressive disease (PD) or death due to any cause, whichever occurs first as assessed by Response Criteria in Solid Tumors Version 1.1 (RECIST 1.1). PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions is also considered PD. PFS as assessed by blinded independent central review (BICR) will be presented.
Time frame: Up to ~57 months
Objective Response Rate (ORR)
ORR is defined as the percentage of participants with Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1). The percentage of participants who experience CR or PR as assessed by Blinded Independent Central Review (BICR) will be presented.
Time frame: Up to ~95 months
Duration of Response (DOR)
For participants who demonstrate a confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1), DOR is defined as the time from first documented evidence of CR or PR until progressive disease (PD) or death. Per RECIST 1.1, PD is defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. The appearance of one or more new lesions is also considered PD. DOR as assessed by Blinded Independent Central Review (BICR) will be presented.
Time frame: Up to ~95 months
Change from baseline in global health status/quality of life scores, on the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30)
The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the questions "How would you rate your overall health during the past week?" and "How would you rate your overall quality of life during the past week?" are 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 score indicates a better overall health status.
Time frame: Baseline and up to ~95 months
Change from baseline in physical functioning score, on the EORTC QLQ-C30
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.
Time frame: Baseline and up to ~95 months
Change from baseline in emotional functioning score, on the EORTC QLQ-C30
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 emotional 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 emotional functioning.
Time frame: Baseline and up to ~95 months
Change from baseline in fatigue score, on the EORTC QLQ-C30
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.
Time frame: Baseline and up to ~95 months
Change from baseline in diarrhea score, on the EORTC QLQ-C30
The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the question "Have you had diarrhea?" 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.
Time frame: Baseline and up to ~95 months
Time to first Deterioration (TTD) in global health status/quality of life scores, on the EORTC QLQ-C30
The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the questions "How would you rate your overall health during the past week?" and "How would you rate your overall quality of life during the past week?" are 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 score indicates a better overall health status. TTD is defined as the time from baseline to the first onset of a 10-point deterioration from baseline in global health status/quality of life combined score.
Time frame: Up to ~95 months
TTD in physical functioning score, on the EORTC QLQ-C30
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. TTD is defined as the time from baseline to the first onset of a 10-point deterioration from baseline in the physical functioning score.
Time frame: Up to ~95 months
TTD in emotional functioning score, on the EORTC QLQ-C30
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 emotional 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 emotional functioning. TD is defined as the time from baseline to the first onset of a 10-point deterioration from baseline in the emotional functioning score.
Time frame: Up to ~95 months
TTD in fatigue score, on the EORTC QLQ-C30
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. TTD is defined as the time from baseline to the first onset of a 10-point deterioration from baseline in the fatigue score.
Time frame: Up to ~95 months
TTD in diarrhea score, on the EORTC QLQ-C30
The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the question about their diarrhea 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. TTD is defined as the time from baseline to the first onset of a 10-point deterioration from baseline in the diarrhea score.
Time frame: Up to ~95 months
Number of participants who experience one or more adverse events (AEs)
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.
Time frame: Up to ~95 months
Number of participants who discontinue study treatment due to an AE
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.
Time frame: Up to ~95 months
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Not enrolling at this site — choose another above.
Showing the first 100 of 259 sites across 40 countries. Choose a country and city above to see the rest.
Plan to share: Yes — https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Data sharing details ↗ · externaldatasharing-msd.com
Started Apr 2024 (actual). Primary completion is estimated for Jul 2027, 38 months after the start.
Of 272 industry-sponsored phase 3 interventional studies under Breast Neoplasms, half reached primary completion within 40 months of starting (the median), counting those still running; a quarter within 28 and three quarters within 63. This study's planned 38 months is close to that.
Counting every sponsor, half of 600 studies reached it within 59 months; a quarter within 36 and three quarters within 96.
How these figures are worked out, and which studies are left out of them.
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 ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions 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 drug tested here: Sacituzumab tirumotecan