Clinical trials · California
Breast cancer clinical trials in California
We’re tracking 238 recruiting breast cancer studies with a site in California — including Phase 1, Phase 1/Phase 2, Phase 2 and Phase 3 studies, each written for real people, not researchers.
Recruiting studies in California
- NCT07383506RecruitingPhase 1
Study of a targeted pill for PIK3CA-mutated advanced cancers
This trial tests a new pill (CGT6297) that targets cancer cells with a specific PIK3CA gene change. It may be an option for people with certain advanced solid tumors, including endometrial or breast cancer, after standard treatments have stopped working.
Los Angeles, CaliforniaAges 18 years+ - NCT07102381RecruitingPhase 2
Zanidatamab plus chemo before surgery for HER2+ breast cancer
This trial tests a new drug called zanidatamab combined with chemotherapy to shrink HER2-positive breast cancer before surgery. It may help improve treatment outcomes for people with stage 2 or 3 breast cancer that has not spread.
Long Beach, CaliforniaAges 18 years+ - NCT07391774RecruitingPhase 3
Hormone therapy with or without chemo for early breast cancer
This trial tests whether skipping chemotherapy and using only hormone therapy with a drug called ribociclib works as well as chemotherapy followed by hormone therapy with ribociclib for certain early breast cancers that have a low risk of coming back.
Auburn, CaliforniaAges 18 years+ - NCT06058377RecruitingPhase 3
Adding immunotherapy to chemo for stage II-III breast cancer
This trial tests whether adding the immunotherapy drug durvalumab to standard chemotherapy works better than chemo alone for people with hormone receptor positive, HER2 negative breast cancer that is stage II or III and has a high-risk genetic score (MammaPrint High Risk 2).
Auburn, CaliforniaAges 18 years+ - NCT07191717RecruitingPhase 2
Imlunestrant and abemaciclib for early ER+ breast cancer
This trial tests whether adding two targeted drugs, imlunestrant and abemaciclib, to your usual hormone therapy can lower the chance of your breast cancer coming back. It is for people with early-stage ER+ breast cancer who have no signs of cancer on scans but have tiny amounts of tumor DNA in their blood (called ctDNA).
Los Angeles, CaliforniaAges 18 years+ - NCT07085767RecruitingPhase 3
Palazestrant and ribociclib for first-line advanced breast cancer
This trial tests a new drug (palazestrant) combined with ribociclib for people with a common type of advanced breast cancer that is estrogen receptor-positive and HER2-negative. You may qualify if you haven't had treatment for advanced disease and your cancer has either just been found or came back long after completing hormone therapy.
Beverly Hills, CaliforniaAges 18 years+ - NCT07541079RecruitingPhase 3
Testing a New Breast Cancer Drug for Women Who Can't Tolerate Current Therapy
This study tests giredestrant, a new hormone-blocking medication, in postmenopausal women with early-stage ER+ breast cancer who have experienced intolerable side effects from their current aromatase inhibitor therapy. The trial will measure how well you tolerate this new drug and how it affects your quality of life.
Fountain Valley, CaliforniaAges 18 years+ - NCT07007559RecruitingPhase 2
Evorpacept with trastuzumab and chemo for HER2-positive breast cancer
This study tests an experimental drug called evorpacept when given with trastuzumab and chemotherapy for people with HER2-positive breast cancer that has spread. The goal is to see if this combination can shrink tumors or slow down the cancer.
Duarte, CaliforniaAges 18 years+ - NCT06518057RecruitingPhase 2
Sparing memory during brain radiation for leptomeningeal metastases
This trial tests a special type of radiation that avoids the memory center of the brain (the hippocampus) while treating cancer that has spread to the lining of the brain and spinal cord. It may help reduce side effects on thinking and memory for people with breast or lung cancer.
San Francisco, CaliforniaAges 18 years+ - NCT04768426RecruitingPhase 2
Watching DNA in blood while taking capecitabine after breast cancer
This trial checks how a blood test that looks for cancer DNA (ctDNA) changes during and after you take capecitabine after early triple-negative breast cancer. It aims to see whether these blood test results can help monitor the chance of the cancer coming back.
Stanford, CaliforniaAges 18 years+ - NCT05304962RecruitingPhase 1
Test drug RGT-419B for advanced ER+ HER2- breast cancer
This Phase 1 study tests a new drug (RGT-419B), given alone or with hormone (endocrine) therapy, in people with advanced ER-positive, HER2-negative breast cancer that has progressed after standard treatments. It looks mainly at safety and early signs of how well the treatment may work.
La Jolla, CaliforniaAges 18 years+ - NCT07405801RecruitingPhase 2
Inavolisib plus ribociclib plus fulvestrant for advanced breast cancer
This trial tests a combination of three drugs (inavolisib, ribociclib, and fulvestrant) compared to a placebo plus two of the drugs (ribociclib and fulvestrant) for people with advanced hormone receptor-positive breast cancer who have not had prior treatment for advanced disease. The goal is to see if adding inavolisib improves outcomes.
Anaheim, CaliforniaAges 18 years+ - NCT07741968Recruiting
Online program to ease fear of cancer returning
This study tests an online program designed to help women with advanced or certain types of breast or gynecologic cancer manage their fear of the disease progressing or returning. The program aims to reduce anxiety and improve quality of life.
Arcadia, CaliforniaAges 18 years+ - NCT07100106RecruitingPhase 1/Phase 2
Study of GDC-4198 alone or with giredestrant for advanced breast cancer
This trial tests a new treatment (GDC-4198) alone or with another drug (giredestrant) compared to a standard combination (abemaciclib and giredestrant) for people with advanced hormone receptor-positive, HER2-negative breast cancer that has progressed after previous treatments.
Duarte, CaliforniaAges 18 years+ - NCT03723928Recruiting
Blood test–guided monitoring for metastatic breast cancer treatment
This study checks whether specific blood “tumor marker” levels can help monitor how hormone receptor–positive, HER2-negative metastatic breast cancer responds to first-line therapy. It uses regular blood tests (and sometimes scans) to see if this marker-based monitoring is useful and reliable.
Irvine, CaliforniaAges 18 years+ - NCT07368998RecruitingPhase 2
Study of inavolisib plus fulvestrant for advanced breast cancer
This trial tests whether a new targeted pill (inavolisib) plus hormone therapy (fulvestrant) can slow or stop breast cancer growth in people whose cancer has a specific genetic change called a PIK3CA mutation. It is for patients whose disease worsened after previous hormone-and-CDK-inhibitor treatment.
Los Angeles, CaliforniaAges 18 years+ - NCT07512271Recruiting
AI Education Tool for Breast Cancer Patients
This study tests a new computer-based education module created by artificial intelligence to help breast cancer patients understand their diagnosis and treatment options. The goal is to see if this tool helps patients feel more informed and prepared for their care.
San Francisco, CaliforniaAges 18 years+ - NCT06042569RecruitingPhase 2
Lower-dose chemo for older women with HER2-negative breast cancer
This trial tests whether a lower dose of two chemotherapy drugs (docetaxel and cyclophosphamide) works well for women 65 and older with early-stage HER2-negative breast cancer. The goal is to maintain effectiveness while reducing side effects in this group.
Duarte, CaliforniaAges 65 years+ - NCT05595499RecruitingPhase 2
Fisetin for better walking and strength in breast cancer survivors
This study tests whether fisetin (a natural compound) can improve physical function, like walking ability, in breast cancer survivors who feel frail. It may help strengthen muscles and improve daily activity after treatment.
Alhambra, CaliforniaAges Any age - NCT06065748RecruitingPhase 3
New hormone therapy for advanced breast cancer after prior treatment
This trial tests a new oral hormone therapy, giredestrant, against a standard hormone therapy (fulvestrant) when both are given with a CDK4/6 inhibitor. It is for people with advanced ER-positive, HER2-negative breast cancer that has come back after initial hormone therapy, and who have not yet had other treatments for advanced disease.
Auburn, CaliforniaAges 18 years+ - NCT07121972Recruiting
Validating AI for breast cancer risk prediction
This trial uses an AI model called Mirai to identify women at high risk for breast cancer based on their mammograms. If you are eligible, you may be invited for a breast MRI to better understand your risk.
San Francisco, CaliforniaAges 40–89 - NCT06763328RecruitingPhase 3
Metformin for insulin resistance after breast cancer chemo
This study tests if metformin, a common diabetes medicine, can help reduce insulin resistance in women who finished chemotherapy for early-stage breast cancer. It aims to improve long-term health and prevent future problems.
Riverside, CaliforniaAges 18 years+ - NCT05786664Recruiting
Breast cancer survivor study collecting your health samples
This study invites women who finished treatment for non-metastatic invasive breast cancer to share health information and biological samples for future research. It may help scientists understand survivorship and improve care after treatment.
Los Angeles, CaliforniaAges 18 years+ - NCT05812807RecruitingPhase 3
Pembrolizumab versus monitoring after triple-negative breast cancer response
This trial checks whether giving pembrolizumab (an immunotherapy) after surgery helps people with triple-negative breast cancer reduce the chance of the cancer coming back, compared with close monitoring only. It’s for patients who had no remaining invasive cancer after neoadjuvant chemotherapy plus pembrolizumab.
Arroyo Grande, CaliforniaAges 18 years+
Breast cancer trials by city in California
Where these studies are running in California
Institutions with a site for the recruiting breast cancer studies listed above.
- City of Hope Comprehensive Cancer Center · 7 studies
- Sutter Medical Center Sacramento · 4 studies
- University of California, Irvine Medical Center / UC Irvine Health · 4 studies
- University of California, San Francisco · 4 studies
- Alta Bates Summit Medical Center · 3 studies
- Cedars-Sinai Cancer - Tarzana · 3 studies
- City of Hope Orange County Lennar Foundation Cancer Center · 3 studies
- Desert Regional Medical Center · 3 studies
What taking part in a breast cancer study involves
A screening visit first
Before anything else, the study team checks whether you fit — usually a visit with some tests. You can stop at any point, and screening is typically free.
Care at a nearby site
Study visits happen at a clinic or hospital taking part. Many studies cover the cost of the study treatment and related visits, and some reimburse travel.
You stay in control
Taking part is voluntary and you can leave a study at any time, for any reason, without affecting your regular care.
The team decides eligibility
Our fit check is a helpful first read, not a decision. The study team makes the final call after reviewing your health history.
Breast cancer trials in other states
Common questions
- Are there breast cancer clinical trials in California?
- Yes. We're currently tracking 238 recruiting breast cancer studies with a site in California, each rewritten in plain language so you can see what it's testing and who it's for.
- How do I find out if I qualify for a breast cancer study in California?
- Each study lists its eligibility rules — age, diagnosis, prior treatments. On every trial page we explain these in plain language and offer a short, optional pre-screen for a fit read. The study team makes the final decision.
- Do I have to live in California to take part?
- Not necessarily. These studies have a site in California, but eligibility is about your health, not your address — some people travel to take part, and a few studies reimburse travel. The study team can tell you what's required.
- Does it cost anything to join a breast cancer trial?
- Using Clin2 is always free. Many trials cover the study treatment and related visits; some reimburse travel. The study team explains exactly what's covered before you decide.
Not the right time?
New breast cancer studies open in California regularly. Set up a health profile and we’ll quietly watch for studies that fit you and email you when one opens.
Clin2 helps you find and understand clinical trials and does not provide medical advice. Study data comes from ClinicalTrials.gov. Talk with your doctor about whether a specific trial is right for you.