27 Breast Cancer Clinical Trials in St Louis, MO (2026)

Q: How do I join a clinical trial in St Louis?

Browse available studies, click one that interests you, and complete the free eligibility form. A study coordinator at the St Louis research site will contact you.

Recruiting Breast Cancer Studies in St Louis

NCT06188520Recruiting

A First-in-human Dose Escalation and Expansion Study to Evaluate the Safety, and Tolerability of AZD8421 Alone or in Combination in Participants With Selected Advanced or Metastatic Solid Tumors

This study is designed to evaluate AZD8421 alone and in combination with selected targeted anti-cancer drugs in patients with ER+HER2- advanced breast cancer, and patients with metastatic high-grade s...

St Louis, MOPHASE1564 participantsAstraZeneca

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NCT07114601Recruiting

A Study of LY4257496 in Participants With Cancer (OMNIRAY)

The main purpose of this study is to evaluate safety, tolerability, and efficacy of LY4257496 alone and as part of relevant standard of care (SOC) combination therapy in participants with Gastrin-rele...

St Louis, MOPHASE1421 participantsEli Lilly and Company

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NCT06981208Recruiting

ChatGPT & Surgeon Synergy: Redefining Breast Reconstruction Consultations for Enhanced Patient Engagement and Satisfaction

In this study, patients who are scheduled for breast reconstruction consultation will be randomized into the intervention group (ChatGPT-generated patient education regarding possible reconstruction o...

St Louis, MONA410 participantsWashington University School of Medicine

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NCT06827236Recruiting

A Clinical Study to Find the Optimal Dose of an Investigational Treatment Called BNT323 When Used in Combination With Another Investigational Treatment, BNT327, and to Test if That Combination Treatment is Safe and Beneficial for Patients With Advanced Breast Cancer

This is a Phase I/II, multi-site, open-label, two-part study designed to evaluate the efficacy, safety, optimized dose and contribution of components of BNT323 in combination with BNT327 in participan...

St Louis, MOPHASE1380 participantsBioNTech SE

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NCT07029399Recruiting

A Study With NKT5097 for Adults With Advanced/Metastatic Solid Tumors

The goal of this open-label dose escalation and expansion study is to evaluate the safety and tolerability of NKT5097 in adults with advanced/metastatic tumors (emphasis on breast cancer and solid tum...

St Louis, MOPHASE1361 participantsNiKang Therapeutics, Inc.

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NCT00353483Recruiting

Effect of Neoadjuvant or Adjuvant Systemic Therapy on Breast Cancers, Bone Marrow Cancer Cells, and Circulating Cancer Cells

The main purpose of this study is to compare genetic markers present on tumor cells before and after chemotherapy....

St Louis, MO300 participantsWashington University School of Medicine

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NCT06864754Recruiting

WashU DIEP Flap Video and Patient Understanding Improvement

Patients will complete a survey before and after watching the WashU DIEP Flap Video at their pre-operative standard of care visit, and a third survey at their post-operative standard of care visit. Th...

St Louis, MONA300 participantsWashington University School of Medicine

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NCT07100106Recruiting

A Study to Evaluate the Effect of GDC-4198 Alone and in Combination With Giredestrant Versus Abemaciclib and Giredestrant in Participants With Locally Advanced or Metastatic Estrogen Receptor-Positive (ER+), Human Epidermal Growth Factor Receptor-Negative (HER2-) Breast Cancer

The purpose of this study is to assess the safety of GDC-4198 alone and in combination with giredestrant and also the efficacy of GDC-4198 + giredestrant versus abemaciclib + giredestrant in participa...

St Louis, MOPHASE1285 participantsGenentech, Inc.

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NCT05890677Recruiting

The LYMPH Trial - Microsurgical Versus Conservative Treatment of Chronic Breast Cancer Associated Lymphedema

The aim of this study is to test whether lymphatic surgery provides better QoL (assessed with the Lymph-ICF-UL, (Lymphedema Functioning Disability and health questionnaire for upper limb lymphedema)) ...

St Louis, MONA280 participantsUniversity Hospital, Basel, Switzerland

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NCT06726148Recruiting

Study of ECI830 Single Agent or in Combination in Patients With Advanced HR+/HER2- Breast Cancer and Other Advanced Solid Tumors

Phase I: Characterize safety and tolerability of ECI830 as a single agent and in combination with ribociclib and fulvestrant. Identify dose range for optimization/recommended dose for future studies. ...

St Louis, MOPHASE1280 participantsNovartis Pharmaceuticals

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NCT06559540Recruiting

Ultra-Hypofractionated vs. Hypofractionated Radiation for Node-Positive Breast Cancer

In breast cancer patients with nodal involvement, numerous studies have demonstrated that adjuvant radiation therapy reduces the risk of local recurrence, regional recurrence, and distant metastases, ...

St Louis, MOPHASE2220 participantsWashington University School of Medicine

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NCT06184750Recruiting

Finding the Best Tamoxifen Dose for Breast Cancer Risk Reduction in Premenopausal Women, RENAISSANCE Trial

This phase II trial evaluates response-guided low-dose tamoxifen for reducing breast density in women who are at higher than average risk for breast cancer. Increasing breast density is a well establi...

St Louis, MOPHASE2200 participantsNational Cancer Institute (NCI)

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NCT05508906Recruiting

Phase 1b Study of OP-1250 (Palazestrant) in Combination With Ribociclib, Alpelisib, Everolimus, or Atirmociclib in ER+, HER2- Breast Cancer

This is a Phase 1b open-label, 2-part study in 3 treatment groups. The 3 treatment groups are as follows: Treatment Group 1: Palazestrant (OP-1250) in combination with ribociclib (KISQALI®, Novartis ...

St Louis, MOPHASE1190 participantsOlema Pharmaceuticals, Inc.

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NCT06374459Recruiting

Zunsemetinib in Combination With Capecitabine in Patients With Hormone Receptor-Positive and HER2-Negative Metastatic Breast Cancer With Bone Metastasis

This is a phase Ib/II study evaluating the safety and efficacy of zunsemetinib (ATI-450) with capecitabine in patients with hormone receptor-positive and HER2-negative (HR+/HER2-) metastatic breast ca...

St Louis, MOPHASE1152 participantsWashington University School of Medicine

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NCT05505643Recruiting

Cryoablation vs Lumpectomy in T1 Breast Cancers

This trial studies the efficacy and safety of cryoablation in patients with low risk, early stage breast cancer. Cryoablation is a method of killing a tumor by freezing it. The standard approach for p...

St Louis, MONA120 participantsWashington University School of Medicine

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NCT06926920Recruiting

A Study of Sacituzumab Govitecan Given at an Alternative Dose and Schedule in Participants With Advanced Triple-Negative Breast Cancer

The goal of this clinical study is to learn more about the study drug sacituzumab govitecan-hziy (SG) given at an alternative dose and schedule, in participants with triple-negative breast cancer (TNB...

St Louis, MOPHASE1100 participantsGilead Sciences

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NCT05972343Recruiting

COOL-IT-PRO: Cryoablation of Breast Cancer in Non-surgical Patients

This is a subject registry study of patients who undergo cryoablation for their breast cancer after being determined not to be surgical candidates. Data collected as part of this registry will be used...

St Louis, MO100 participantsWashington University School of Medicine

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NCT07222267Recruiting

An Investigational Study of BG-75202 Alone and in Combination With Other Therapeutic Agents in Adults With Advanced Solid Tumors

The purpose of this study is to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and preliminary antitumor activity of BG-75202 (KAT6A/B inhibitor) alone and in combination ...

St Louis, MOPHASE186 participantsBeOne Medicines

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NCT05837455Recruiting

NeoTAILOR: ABiomarker-directed Approach to Guide Neoadjuvant Therapy for Patients With Stage II/III ER-positive, HER2-negative Breast Cancer

This study aims to utilize a novel biomarker-driven approach to guide neoadjuvant treatment selection. It is the hypothesis that this will improve clinical response for postmenopausal women with clini...

St Louis, MOPHASE281 participantsWashington University School of Medicine

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NCT05977036Recruiting

BettER: Biomarker Driven Early Therapeutic Selection in Patients With HR+ HER2- Metastatic or Unresectable Breast Cancer

This is a prospective study to assess the impact of biomarker driven, early therapeutic switching and delayed imaging with the incorporation of DiviTum® serum TK1 activity ("DiviTum® TKa") in patients...

St Louis, MONA65 participantsWashington University School of Medicine

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NCT05304962Recruiting

FIH Study of RGT-419B Alone and With Endocrine Therapy in HR-Positive, HER2-Negative Advanced/Metastatic Breast Cancer

This is a phase I, First-in-Human (FIH), open-label study to evaluate the safety, tolerability, pharmacokinetic (PK) profile, and preliminary efficacy of RGT-419B administered orally as monotherapy OR...

St Louis, MOPHASE164 participantsRegor Pharmaceuticals Inc.

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NCT06179303Recruiting

Functional Imaging in Prediction of Response to Abemaciclib for Advanced Hormone Receptor-Positive, HER2-Negative Breast Cancer

This phase II trial tests the accuracy of functional imaging (FFNP)-positron emission tomography (PET)/computed tomography (CT) to predict response to abemaciclib plus endocrine therapy. Abemaciclib i...

St Louis, MOPHASE260 participantsUniversity of Washington

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NCT04968964Recruiting

Treatment Monitoring of Patients Receiving CDK 4/6 Inhibitors for Hormone Receptor (HR) Positive, HER2 Negative Metastatic Breast Cancer (MBC) With or Without the Addition of DiviTum® Serum Thymidine Kinase 1 (TK1) Activity Testing

Historically, serial testing of patients with metastatic breast cancer has included a combination of physical exam, symptom evaluation, laboratory testing, and imaging. Circulating tumor biomarkers ar...

St Louis, MONA55 participantsWashington University School of Medicine

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NCT02476786Recruiting

Endocrine Treatment Alone for Elderly Patients With Estrogen Receptor Positive Operable Breast Cancer and Low Recurrence Score

Multiple neoadjuvant endocrine trials demonstrate that women with good prognosis tumors can be identified. These trials have also demonstrated that there are not adverse effects on overall outcome if ...

St Louis, MOPHASE250 participantsWashington University School of Medicine

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NCT07137416Recruiting

Testing the Safety of the Combination of Anti-Cancer Drugs CX-5461 (Pidnarulex) and Trastuzumab Deruxtecan (T-DXd) for Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Solid Tumors and Breast Cancer

This phase I trial tests the safety, side effects, and best dose of pidnarulex in combination with trastuzumab deruxtecan in treating patients with breast cancer and other solid tumors that express va...

St Louis, MOPHASE136 participantsNational Cancer Institute (NCI)

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NCT07427394Recruiting

Study to Evaluate the Safety and Tolerability of Camizestrant in Combination With Atirmociclib in Women With Advanced Breast Cancer

A study to investigate camizestrant in combination with atirmociclib in participants with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast canc...

St Louis, MOPHASE224 participantsAstraZeneca

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NCT02422641Recruiting

Prospective Evaluation Of High-Dose Systemic Methotrexate In Patients With Breast Cancer And Leptomeningeal Metastasis

Management of leptomeningeal disease (LMD) in patients with metastatic breast cancer is an area of unmet clinical need. High-dose methotrexate (HD-MTX) is known to have activity against breast cancer ...

St Louis, MOPHASE216 participantsWake Forest University Health Sciences

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About Breast Cancer Clinical Trials in St Louis

Breast cancer is a disease in which cells in the breast grow out of control. It is the most common cancer in women worldwide and can also occur in men. Treatment options include surgery, radiation, chemotherapy, hormone therapy, and targeted therapies.

There are currently 27 breast cancer clinical trials recruiting participants in St Louis, MO. These studies are seeking a combined 5,200 participants. Research is being sponsored by AstraZeneca, Eli Lilly and Company, Washington University School of Medicine and 12 other organizations. Clinical trial participation is free and participants receive study-related medical care at no cost.

Breast Cancer Clinical Trials in St Louis — FAQ

Are there breast cancer clinical trials in St Louis?

Yes, there are 27 breast cancer clinical trials currently recruiting in St Louis, MO. Browse the studies on this page to find one that fits.

How do I join a clinical trial in St Louis?

Browse the studies listed above, click one that interests you, and complete the free eligibility form. A study coordinator at the St Louis research site will contact you about next steps.

Are clinical trials in St Louis free?

Yes, clinical trial participation is always free. Study-related treatment, medical tests, and doctor visits are provided at no cost. Many St Louis studies also compensate for your time and travel.

What breast cancer treatments are being tested?

The 27 active trials in St Louis are testing new therapies including novel drugs, biologics, and treatment approaches for breast cancer.

Data updated July 17, 2026 from ClinicalTrials.gov