18 and older, any sex, with Anatomic Stage IV Breast Cancer AJCC v8 or Prognostic Stage IV Breast Cancer AJCC v8. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Overall Response Rate (ORR)Primary· Up to 24 weeks
ORR is defined as the proportion of participants randomized to that arm whose status is stable disease (SD) or better (complete response (CR), partial response (PR)). Per Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0) for target lesions: CR=Disappearance of all target lesions; PR = \>=30% decrease in the sum of the longest diameter of target lesions, and SD=Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease,.
Group
Value
95% CI
Arm B (Pembrolizumab, Tamoxifen)
0
Percentage of Participants With Tumor ResponsesSecondary· Up to 24 months
Tumor responses will be classified using the Immune Related Response-Criteria (irRC)) through study completion.
Group
Value
95% CI
Arm B (Pembrolizumab, Tamoxifen)
0
Duration of Response (DOR)Secondary· Up to 24 weeks
The duration of overall response is measured from the time measurement criteria are met for CR or PR (whichever is first recorded) until the first date that recurrent or progressive disease is objectively documented (taking as reference for progressive disease the smallest measurements recorded since the treatment started). The duration of overall CR is measured from the time measurement criteria are first met for CR until the first date that recurrent disease is objectively documented. Duration of stable disease is measured from the start of the treatment until the criteria for progression ar
Group
Value
95% CI
Arm B (Pembrolizumab, Tamoxifen)
NA
NA – NA
Median Progression Free Survival (PFS)Secondary· Up to 27 months
Progression-free survival (PFS) is defined as the duration of time from start of treatment to time of progression or death from any cause on study, whichever occurs first. Will use median PFS (computed by the Kaplan-Meier estimator) to summarize. The respective confidence intervals will be computed as well.
Group
Value
95% CI
Arm B (Pembrolizumab, Tamoxifen)
NA
NA – NA
Median Overall Survival (OS)Secondary· Up to 27 months
Will use median OS (computed by the Kaplan-Meier estimator) to summarize from initiation of study treatment to the time of death from any cause on study. The respective confidence intervals will be computed as well.
Group
Value
95% CI
Arm B (Pembrolizumab, Tamoxifen)
NA
NA – NA
Sponsor's own description
This phase II trial studies how well pembrolizumab and tamoxifen with or without vorinostat work for the treatment of estrogen receptor positive breast cancer. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Estrogen can cause the growth of breast cancer cells. Hormone therapy with tamoxifen may may fight breast cancer by blocking the use of estrogen by the tumor cells. Vorinostat may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. This trial is being done to find a drug combination to better control estrogen receptor positive breast cancer and reduce the number of pills taken.
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
NCT07572123 — Evaluating the Addition of Maintenance Immunotherapy Compared to the Usual Treatment of Chemotherapy and Autologous Stem
· Phase 2, PHASE3
· not yet recruiting
NCT07275216 — Pembrolizumab in Combination With Chemotherapy for the Treatment of Frail Hodgkin Lymphoma Patients Ineligible for Stand
· Phase 2
· not yet recruiting
NCT07302347 — A Study of Pembrolizumab in Japanese Pediatric Participants With Solid Tumors or Lymphomas and Japanese Adult Participan
· Phase 1, PHASE2
· recruiting
NCT06724042 — Study of ISM5939 in Patients With Advanced and/or Metastatic Solid Tumors
· Phase 1
· not yet recruiting
NCT07383441 — Adding Biotherapy or Placebo to Standard Treatment for Advanced Kidney Cancer
· Phase 3
· not yet recruiting
Other recruiting trials for Anatomic Stage IV Breast Cancer AJCC v8
Currently open trials in the same condition.
NCT07137416 — Testing the Safety of the Combination of Anti-Cancer Drugs CX-5461 (Pidnarulex) and Trastuzumab Deruxtecan (T-DXd) for H
· Phase 1
· recruiting
NCT06860815 — Cemiplimab and Transarterial Radioembolization With Y-90 SIR-S Spheres for the Treatment of Liver Directed Metastatic Br
· Phase 2
· recruiting
NCT07078604 — A Cancer Vaccine (STEMVAC) in Combination With Chemotherapy for the Treatment of PD-L1 Negative Metastatic Triple-Negati
· Phase 2
· recruiting
NCT06434064 — Tamoxifen and Pegylated Liposomal Doxorubicin for the Treatment of Patients With Metastatic or Inoperable, Locally Advan
· Phase 2
· recruiting
NCT06502691 — [18F]FTT Positron Emission Tomography for the Measurement of PARP Tumor Expression in Patients With Metastatic Breast Ca
· Phase 1, PHASE2
· recruiting
Other University of California, San Francisco trials
Trials by the same sponsor.
NCT05284773 — Screening for Acute Malnutrition
· NA
· withdrawn
NCT04634851 — Video Home Visits for Dietary Counselling
· NA
· not yet recruiting
NCT06065670 — Assessing Changes in Multi-parametric MRI in Patients With Acute Demyelinating Lesions Taking Clemastine Fumarate as a M
· Phase 1, PHASE2
· not yet recruiting
NCT07534098 — Intervention for Hearing Health Among Native Americans
· NA
· not yet recruiting
NCT06960421 — Exercise-based Frailty Intervention in Lung Transplantation (XFIT)
· NA
· not yet recruiting
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by University of California, San Francisco
Last refreshed: 31 August 2023
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT04190056.