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Breast Cancer clinical trials in Seattle, WA
37 studies for Breast Cancer are looking for participants at sites in and around Seattle (within about 30 miles). Open a study to see who can join and how to contact the study team.
Recruiting for a study here? Feature it at the top of this page — $99 for 30 days →
A Study to Evaluate the Efficacy and Safety of Inavolisib in Combination With Phesgo Versus Placebo in Combination With Phesgo in Participants With PIK3CA-Mutated HER2-Positive Locally Advanced or Metastatic Breast Cancer
RecruitingPhase 3
- Swedish Medical Center, Seattle
An Investigational Study of BG-75202 Alone and in Combination With Other Agents in Adults With Advanced Solid Tumors
RecruitingPhase 1
- Fred Hutchinson Cancer Research Center, Seattle
S1501 Dual Observational and Randomized Cohort Study of Patients With Metastatic HER-2+ Breast Cancer at Risk of Cardiac Toxicity
RecruitingPhase 3
- FHCC South Lake Union, Seattle
- Swedish Medical Center-First Hill, Seattle
- University of Washington Medical Center - Montlake, Seattle
Trial of 225Ac-DOTATATE (RYZ101) in Subjects With ER+, HER2-negative Unresectable or Metastatic Breast Cancer Expressing SSTRs.
RecruitingPhase 1/2
- Research Facility, Seattle
A Clinical Study of Sacituzumab Tirumotecan (Sac-TMT, MK-2870) in People With Breast Cancer (MK-2870-032)
RecruitingPhase 3
- Fred Hutchinson Cancer Center ( Site 0069), Seattle
ASPEN-09-03: A Study of Evorpacept in Combination With Trastuzumab and Chemotherapy in Metastatic HER2-Positive Breast Cancer
RecruitingPhase 2
- Fred Hutchinson Cancer Center, Seattle
Beamion BCGC-1: A Study to Find a Suitable Dose of Zongertinib Used Alone and in Combination With Other Treatments to Test Whether it Helps People With Different Types of HER2+ Cancer That Has Spread
RecruitingPhase 1/2
- Fred Hutchinson Cancer Research Center, Seattle
Signatera-Guided CDK4/6 Inhibitor Therapy in Breast Cancer
Recruiting
- Fred Hutch Cancer Center, Seattle
A Study of Tersolisib (LY4064809/STX-478) With Other Anti-Cancer Treatments in Participants With Advanced Breast Cancer With a Genetic Change (PIK3CA)
RecruitingPhase 3
- Swedish Medical Center, Seattle
A Study Evaluating the Efficacy and Safety of Inavolisib Plus CDK4/6 Inhibitor and Letrozole vs Placebo + CDK4/6i and Letrozole in Participants With Endocrine-Sensitive PIK3CA-Mutated, Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer
RecruitingPhase 3
- Swedish Cancer Institute - Issaquah, Seattle
- Swedish Cancer Institute, Seattle
E-Mindfulness Approaches for Living After Breast Cancer
RecruitingPhase 3
- Saint Joseph Medical Center Hematology and Oncology - Silverdale, Silverdale · 17 mi away
Collecting Blood Samples From Patients With and Without Cancer to Evaluate Tests for Early Cancer Detection
RecruitingObservational studyHealthy volunteers welcome
- Swedish Medical Center-Ballard Campus, Seattle
- Swedish Medical Center-Cherry Hill, Seattle
- Swedish Medical Center-First Hill, Seattle
- and 1 more
Assessing Benefits and Harms of Cannabis/Cannabinoid Use Among Cancer Patients Treated in Community Oncology Clinics
RecruitingObservational study
- Swedish Medical Center-Ballard Campus, Seattle
- Kaiser Permanente Washington, Seattle
- Swedish Medical Center-First Hill, Seattle
Evaluating the Addition of Adjuvant Chemotherapy to Ovarian Function Suppression Plus Endocrine Therapy in Premenopausal Patients With pN0-1, ER-Positive/HER2-Negative Breast Cancer and an Oncotype Recurrence Score Less Than or Equal to 25
RecruitingPhase 3
- Virginia Mason Medical Center, Seattle
- Swedish Medical Center-Ballard Campus, Seattle
- Fred Hutchinson Cancer Center, Seattle
- and 5 more
The CDK4/6 Inhibitor Dosing Knowledge (CDK) Study
RecruitingPhase 3
- Fred Hutchinson Cancer Center, Seattle
- Fred Hutchinson Cancer Center at University of Washington-Northwest, Seattle
A Study to Learn About the Study Medicine Called PF-07248144 in Combination With Fulvestrant in People With HR-positive, HER2-negative Advanced or Metastatic Breast Cancer Who Progressed After a Prior Line of Treatment.
RecruitingPhase 3
- Harborview Medical Center, Seattle
- Fred Hutchinson Cancer Center, Seattle
- University of Washington Medical Center, Seattle
Phase 1/2 Study of ETX-636 in Participants With Advanced Solid Tumors
RecruitingPhase 1/2
- Fred Hutchinson Cancer Center, Seattle
Phase 3 Study of Gedatolisib as First-Line Treatment for Patients With HR-Positive, HER2-Negative Advanced Breast Cancer (VIKTORIA-2)
RecruitingPhase 3
- Fred Hutchinson Cancer Center, Seattle
The Evaluation of PC14586 in Patients With Advanced Solid Tumors Harboring a TP53 Y220C Mutation (PYNNACLE)
RecruitingPhase 1/2
- University of Washington, Fred Hutchinson Cancer Center, Seattle
Open-Label Study of BBO-10203 in Subjects With Advanced Solid Tumors
RecruitingPhase 1
- Fred Hutchinson Cancer Center, Seattle
Palazestrant in Combination With Ribociclib for the First-line Treatment of ER+/HER2- Advanced Breast Cancer
RecruitingPhase 3
- Clinical Trial Site, Seattle
A Study to Evaluate the Safety, Tolerability, Drug Levels, and Preliminary Efficacy of BMS-986507 Combinations in Adult Participants With Advanced Solid Tumors
RecruitingPhase 1/2
- Swedish Medical Center, Seattle
ARTIDIS Nanomechanical Generated Measurements for Early Breast Lesions
Recruiting
- University of Washington, Seattle
BGB-21447 (Bcl-2 Inhibitor) Combinations for Adults With Hormone-Receptor Positive (HR+)/Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Metastatic Breast Cancer
RecruitingPhase 1
- Fred Hutchinson Cancer Research Center, Seattle
A Phase 1/1b Study of IAM1363 in HER2 Cancers
RecruitingPhase 1
- Fred Hutchinson Cancer Center, Seattle
Study of ECI830 Single Agent or in Combination in Patients With Advanced HR+/HER2- Breast Cancer and in Patients With Other Advanced Solid Tumors
RecruitingPhase 1/2
- Fred Hutch Cancer Research, Seattle
Hippocampal Avoidance in Craniospinal Irradiation for the Treatment of Leptomeningeal Metastases From Breast Cancer or Non-small Cell Lung Cancer
RecruitingPhase 2
- Fred Hutch/University of Washington Cancer Consortium, Seattle
Phase I Study of [177Lu]Lu-NNS309 in Patients With Pancreatic, Lung, Breast and Colorectal Cancers
RecruitingPhase 1
- University Of Washington, Seattle
A Study to Assess the Efficacy and Safety of FORE8394 in Participants With Cancer Harboring BRAF Alterations
RecruitingPhase 2
- University of Washington School of Medicine, Seattle
A Study of Emiltatug Ledadotin (Emi-Le) in Participants With Solid Tumors
RecruitingPhase 1/2
- Fred Hutchinson Cancer Center, Seattle
[18F]FTT Positron Emission Tomography for the Measurement of PARP Tumor Expression in Patients With Metastatic Breast Cancer
RecruitingPhase 1/2
- Fred Hutch/University of Washington Cancer Consortium, Seattle
De-Escalation of Breast Radiation Trial for Hormone Sensitive, HER-2 Negative, Oncotype Recurrence Score Less Than or Equal to 18 Breast Cancer (DEBRA)
RecruitingPhase 3
- Swedish Medical Center-Ballard Campus, Seattle
- Swedish Medical Center-First Hill, Seattle
- Saint Michael Cancer Center, Silverdale · 17 mi away
Quantitative MRI Assessment of Breast Cancer Therapy Response
RecruitingObservational study
- University of Washington, Seattle
A Study of PARG Inhibitor ETX-19477 in Patients With Advanced Solid Malignancies
RecruitingPhase 1/2
- Fred Hutchinson Cancer Center, Seattle
A Study of CLSP-1025 in Adult Patients With Solid Tumors That Harbor the p53 R175H Mutation
RecruitingPhase 1
- Fred Hutchinson Cancer Center, Seattle
SYNERGY-AI: Artificial Intelligence Based Precision Oncology Clinical Trial Matching and Registry
RecruitingObservational study
- Massive Bio SYNERGY-AI site, Seattle
MammaPrint, BluePrint, and Full-genome Data Linked With Clinical Data to Evaluate New Gene EXpression Profiles
RecruitingObservational study
- Swedish Cancer Institute, Seattle
- Seattle Cancer Care Alliance, Seattle
About Breast Cancer
Breast cancer is a cancer that starts in the breast tissue, when cells change and grow out of control. Learn about the types, diagnosis, and treatments.
More about Breast Cancer on MedlinePlus
Breast Cancer trials in other cities
- New York City, NY144 studies
- Houston, TX126 studies
- Boston, MA110 studies
- Nashville, TN78 studies
- Los Angeles, CA73 studies
- Edison, NJ70 studies
- Queens, NY67 studies
- Durham, NC63 studies
- St. Louis, MO63 studies
- Chicago, IL59 studies
- Dallas, TX54 studies
- Philadelphia, PA51 studies
Other studies in Seattle
- Non-Small Cell Lung Cancer55 studies
- Cancer (all types)48 studies
- Prostate Cancer45 studies
- Acute Myeloid Leukemia40 studies
- Metastatic Cancer39 studies
- Colorectal Cancer35 studies
- Lung Cancer34 studies
- Ovarian Cancer29 studies
- Pancreatic Cancer22 studies
- Multiple Myeloma22 studies
- Acute Lymphoblastic Leukemia22 studies
- Chronic Lymphocytic Leukemia22 studies
From ClinicalTrials.gov, data retrieved Nov 15, 2026. Each study sets its own eligibility; the study team decides who can join.