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ClinicalTrials.gov 423 recruiting now early-phase tilt #1 of 28,707 conditions

Breast Cancer: early-phase trial registry

423 of 1,251 indexed Breast Cancer trials are currently recruiting, with more weight in Phase 1-2.

Corpus placement: #1 of 28,707 conditions by registered trial count.

1,251 US clinical trials · 423 currently recruiting · #1 of 28,707 conditions by registered trial count

Breast Cancer: 1,251 US clinical trials tracked, 423 recruiting.

Breast Cancer is the subject of 1,251 registered US clinical trials on ClinicalTrials.gov, 423 of them currently open to new participants. 120 are in Phase 3-4 (later-stage) and 491 in Phase 1-2 (earlier-stage). The most active sponsor is Memorial Sloan Kettering Cancer Center, running 98 of these trials.

Enrollment posture brief

Registry condition breast-cancer

OPEN 423 | RECR 34% | LATE 120 | EARLY 491 | RANK #1 | SPON 98

Nearest open-share peer: Refractory Multiple Myeloma (34% recruiting · 68 trials)

Prostate Cancer36.7%Depression35.7%Breast Cancer (this)34%Obesity28.9%Healthy20.5%
Open-enrollment share among volume-matched conditions near Breast Cancer

Breast Cancer lists 423 open slots (34% of 1,251 indexed trials). Peers are matched on registered volume, not therapeutic-area browse lists. How peer matching works →

Key findings

What ClinicalTrials.gov does not surface for Breast Cancer on its own pages , computed from the registry mirror as of 2026-08-08. Each line carries its own denominator so it can be quoted as it stands.

  1. Breast Cancer is recruiting below its size-band peers.

    423 of 1,251 indexed trials (33.8%) are open to enrollment, against a 37.1% average across 139 conditions with 100+ trials. The peer set uses the same ClinicalTrials.gov-derived counts as this page.

  2. Sponsorship of Breast Cancer trials is spread across many organizations.

    Memorial Sloan Kettering Cancer Center accounts for 98 of 1,251 trials (7.8%). 367 distinct sponsors appear on at least one study for this condition label.

  3. Typical Breast Cancer enrolment sits around 90 participants.

    Median target enrolment is 90 among the 1,225 trials that report a genuine target (sentinel values excluded). 630 of those (51.4%) plan for fewer than 100 participants.

  4. Breast Cancer research is mostly interventional.

    1,015 interventional and 236 observational studies make up this index (81.1% interventional). Study type is sponsor-reported on ClinicalTrials.gov.

Phase 1235Phase 2256Phase 3100Phase 420

Open and recent trials

1,251 total, page 12 of 26

ACTIVE NOT RECRUITING Phase 2 138 participants

Neoadjuvant Her2-targeted Therapy and Immunotherapy With Pembrolizumab [IIT2018-04-MCARTHUR-NEOHP]

University of Texas Southwestern Medical Center

NCT03747120

ACTIVE NOT RECRUITING NA 137 participants

Hypofractionated Regional Nodal Irradiation Clinical Trial for Women With Breast Cancer

Virginia Commonwealth University

NCT02515110

ACTIVE NOT RECRUITING NA 135 participants

Testing Home-based Exercise Strategies in Underserved Minority Cancer Patients Undergoing Chemotherapy: the THRIVE Study

Dana-Farber Cancer Institute

NCT05327452

ACTIVE NOT RECRUITING Phase 2 135 participants

A Study of BB-1701 in Previously Treated Participants With Human Epidermal Growth Factor Receptor 2 (HER2)-Positive or HER2-low Unresectable or Metastatic Breast Cancer

Eisai

NCT06188559

ACTIVE NOT RECRUITING Phase 2 134 participants

Stereotactic Brain-directed Radiation With or Without Aguix Gadolinium-Based Nanoparticles in Brain Metastases

Brigham and Women's Hospital

NCT04899908

ACTIVE NOT RECRUITING NA 134 participants

Single Fraction Accelerated Partial Breast Irradiation vs. Five Fraction Accelerated Partial Breast Irradiation for Low-risk Stage 0 and I Breast Carcinoma

Washington University School of Medicine

NCT04849871

ACTIVE NOT RECRUITING Phase 1 134 participants

A Phase 1 Study of ATV-1601 in Patients With Advanced Cancer That Have AKT1 E17K Mutations

Atavistik Bio

NCT07038369

ACTIVE NOT RECRUITING Phase 1 130 participants

Study of CBX-12 in Subjects With Advanced or Metastatic Refractory Solid Tumors

Cybrexa Therapeutics

NCT04902872

ACTIVE NOT RECRUITING Phase 1 130 participants

Study of NGM831 as Monotherapy and in Combination With Pembrolizumab or Pembrolizumab and NGM438 in Advanced or Metastatic Solid Tumors

NGM Biopharmaceuticals

NCT05215574

ACTIVE NOT RECRUITING NA 130 participants

Controlled Low Calorie Diet in Reducing Side Effects and Increasing Response to Chemotherapy in Patients With Breast or Prostate Cancer

University of Southern California

NCT01802346

ACTIVE NOT RECRUITING Phase 2 128 participants

Extension Study of Lapatinib Plus Herceptin With or Without Endocrine Therapy

Baylor Breast Care Center

NCT00999804

ACTIVE NOT RECRUITING NA 126 participants

Gut Microbe Composition, Exercise, and Breast Breast Cancer Survivors

University of Alabama at Birmingham

NCT04088708

ACTIVE NOT RECRUITING Phase 1 125 participants

A Phase 1-2 Study of ST101 in Patients With Advanced Solid Tumors

Sapience Therapeutics

NCT04478279

ACTIVE NOT RECRUITING 125 participants

Multi-Institutional Transgender & Gender-Diverse Breast Cancer Study

Medical College of Wisconsin

NCT06234488

ACTIVE NOT RECRUITING Phase 2 121 participants

Combination Chemotherapy With or Without Trastuzumab in Treating Patients With Stage II or Stage III Breast Cancer

City of Hope Medical Center

NCT00295893

ACTIVE NOT RECRUITING NA 121 participants

Accelerated Partial Breast Irradiation Following Lumpectomy for Breast Cancer

Stanford University

NCT00185744

ACTIVE NOT RECRUITING Phase 2 121 participants

Letrozole Plus Ribociclib or Placebo as Neo-adjuvant Therapy in ER-positive, HER2-negative Early Breast Cancer

Qamar Khan

NCT02712723

ACTIVE NOT RECRUITING Phase 2 120 participants

CDK 4/6 Inhibitor, Ribociclib, With Adjuvant Endocrine Therapy for ER-positive Breast Cancer

Massachusetts General Hospital

NCT03285412

ACTIVE NOT RECRUITING Phase 2 120 participants

Phase IIB Trial of Bazedoxifene Plus Conjugated Estrogens

University of Kansas Medical Center

NCT04821141

ACTIVE NOT RECRUITING NA 120 participants

The Active After Cancer Trial (AACT)

Dana-Farber Cancer Institute

NCT00548236

ACTIVE NOT RECRUITING Phase 1 115 participants

DS8201a and Pembrolizumab in Participants With Locally Advanced/Metastatic Breast or Non-Small Cell Lung Cancer

Daiichi Sankyo

NCT04042701

ACTIVE NOT RECRUITING Phase 1 113 participants

Malignant Pleural Disease Treated With Autologous T Cells Genetically Engineered to Target the Cancer-Cell Surface Antigen Mesothelin

Memorial Sloan Kettering Cancer Center

NCT02414269

ACTIVE NOT RECRUITING Phase 2 110 participants

Partial Breast Irradiation (PBI) Using 40 Gy for Select Patients With Early Invasive or Noninvasive Breast Cancer

Memorial Sloan Kettering Cancer Center

NCT01203839

ACTIVE NOT RECRUITING Phase 2 110 participants

Preoperative Single-Fraction Radiotherapy in Early Stage Breast Cancer

Duke University

NCT02482376

ACTIVE NOT RECRUITING Phase 2 108 participants

Shorter Course Radiation for the Treatment of Breast Cancer That Has Spread to Lymph Nodes

University of Colorado, Denver

NCT02700386

ACTIVE NOT RECRUITING NA 104 participants

Excision Followed by Radiofrequency Ablation for Breast Cancer

University of Arkansas

NCT01153035

ACTIVE NOT RECRUITING NA 102 participants

Taking AIM at Breast Cancer

Dana-Farber Cancer Institute

NCT04720209

ACTIVE NOT RECRUITING NA 100 participants

Node Negative, Invasive Breast Cancer Single Fraction IOERT

Avera McKennan Hospital & University Health Center

NCT02370797

ACTIVE NOT RECRUITING NA 100 participants

Survivorship Care Planning in Improving the Quality of Life in Breast Cancer Survivors

City of Hope Medical Center

NCT01824745

ACTIVE NOT RECRUITING Phase 1 100 participants

LS301-IT in Partial Mastectomy and Sentinel Lymph Node Biopsy (SLNB) for DCIS or Stage I-II Primary Invasive Breast Cancer

Integro Theranostics

NCT05900986

ACTIVE NOT RECRUITING Phase 1 100 participants

DAPHNe: Paclitaxel/Trastuzumab/Pertuzumab in HER2-Positive BC

Dana-Farber Cancer Institute

NCT03716180

ACTIVE NOT RECRUITING Phase 1 100 participants

A Study of Abemaciclib (LY2835219) in Participants With Non-Small Cell Lung Cancer or Breast Cancer

Eli Lilly and Company

NCT02779751

ACTIVE NOT RECRUITING NA 100 participants

Exploring the Efficacy and Feasibility of the LymphaTech Scanner for Breast Cancer-Related Lymphedema Screening

Massachusetts General Hospital

NCT03861975

ACTIVE NOT RECRUITING Phase 1 100 participants

Study of AC699 in Patients With Estrogen Receptor Positive/Human Epidermal Growth Factor Receptor 2 Negative (ER+/HER2-) Locally Advanced or Metastatic Breast Cancer

Accutar Biotechnology

NCT05654532

ACTIVE NOT RECRUITING Phase 2 100 participants

The AVIATOR Study: Trastuzumab and Vinorelbine With Avelumab OR Avelumab & Utomilumab in Advanced HER2+ Breast Cancer

Adrienne G. Waks

NCT03414658

ACTIVE NOT RECRUITING NA 100 participants

Real World Treatment Experience of Patients With Breast, Lung, or GI Cancer or Multiple Myeloma Using Remote Symptom Monitoring

Carevive Systems

NCT05587972

ACTIVE NOT RECRUITING Phase 1 98 participants

A Study of SNS-101 (Anti VISTA) Monotherapy and in Combination With Cemiplimab in Patients With Advanced Solid Tumors

Sensei Biotherapeutics

NCT05864144

ACTIVE NOT RECRUITING NA 96 participants

Tc99m Sestamibi Molecular Breast Imaging

M.D. Anderson Cancer Center

NCT02324387

ACTIVE NOT RECRUITING Phase 2 91 participants

Evaluating the Safety and Efficacy of a Novel Accelerated Partial Breast Irradiation Regimen

Sanford Health

NCT05591547

ACTIVE NOT RECRUITING Phase 2 90 participants

TRADE: Dose Escalation Tolerability of Abemaciclib in HR+ HER2- Early Stage Breast Cancer

Dana-Farber Cancer Institute

NCT06001762

ACTIVE NOT RECRUITING Phase 1 88 participants

Accelerated Radiation Therapy (ART) to the Breast and Nodal Stations

Weill Medical College of Cornell University

NCT02917421

ACTIVE NOT RECRUITING NA 88 participants

Use of an Interactive 3D Tool During Consultation for Breast Reconstruction Surgery

Memorial Sloan Kettering Cancer Center

NCT05025020

ACTIVE NOT RECRUITING Phase 2 88 participants

Pertuzumab and Trastuzumab as Neoadjuvant Treatment in Patients With HER2-Positive Breast Cancer

Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins

NCT01937117

ACTIVE NOT RECRUITING Phase 2 84 participants

Low-Dose Tamoxifen Citrate in Reducing Breast Cancer Risk in Radiation-Induced Cancer Survivors

University of Alabama at Birmingham

NCT01196936

ACTIVE NOT RECRUITING Phase 2 83 participants

A Study of Tobemstomig + Nab-Paclitaxel Compared With Pembrolizumab + Nab-Paclitaxel in Participants With Previously Untreated, PD-L1-Positive, Locally-Advanced Unresectable or Metastatic Triple-Negative Breast Cancer

Hoffmann-La Roche

NCT05852691

ACTIVE NOT RECRUITING Phase 2 82 participants

ATOP TRIAL: T-DM1 in HER2 Positive Breast Cancer

Dana-Farber Cancer Institute

NCT03587740

ACTIVE NOT RECRUITING Phase 2 82 participants

STOP-HER2: Stopping Trastuzumab in HER2+ MBC

Dana-Farber Cancer Institute

NCT05721248

ACTIVE NOT RECRUITING NA 81 participants

Partial Irradiation and Sequential vs. Concurrent Chemo Early Breast Cancer

Richard Zellars

NCT01928589

ACTIVE NOT RECRUITING Phase 1 80 participants

A Study of YL202 in Patients With Locally Advanced or Metastatic Non-small Cell Lung Cancer and Breast Cancer

MediLink Therapeutics (Suzhou) Co.

NCT05653752

ACTIVE NOT RECRUITING Phase 2 80 participants

The Effect of Acupuncture on Nerve Pain Caused by Taxane (Chemotherapy) Treatment

Memorial Sloan Kettering Cancer Center

NCT05458284

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Phase Distribution

PhaseTrial count
Phase 1 235
Phase 2 256
Phase 3 100
Phase 4 20

Named interventions

Most-linked intervention names on Breast Cancer records (sponsor-reported on ClinicalTrials.gov). Counts are trial links, not unique products.

Fulvestrant Drug
33 trials
Paclitaxel Drug
32 trials
Trastuzumab Drug
26 trials
Letrozole Drug
24 trials
Pembrolizumab Drug
23 trials
Cyclophosphamide Drug
21 trials
Capecitabine Drug
20 trials
Abemaciclib Drug
19 trials

US sites by state

Facility locations filed on Breast Cancer trials. A trial with sites in several states counts in each.

California 298 trials
New York 270 trials
Texas 210 trials
Florida 206 trials
Massachusetts 184 trials
North Carolina 126 trials
Illinois 123 trials
Pennsylvania 122 trials

Source: ClinicalTrials.gov, National Library of Medicine. Data is informational only.

What to do with this Breast Cancer page

1,251 registered trials, 423 currently recruiting, is a starting point for a conversation, not a diagnosis or a recommendation.

Trial and recruiting counts reflect ClinicalTrials.gov registry status as of the data vintage above; individual trial eligibility and enrollment status can change.

Every figure on PlainTrial is rendered directly from the ClinicalTrials.gov registry, no number is typed in by an editor. This Breast Cancer condition card totals 1,251 registered trials; most-linked intervention Fulvestrant; top US site state California. See our editorial standards & corrections policy, the methodology behind these numbers, the data changelog, or report a data error.