Clinical trials · California
Breast cancer clinical trials in California
We’re tracking 244 recruiting breast cancer studies with a site in California — including Phase 1, Phase 1/Phase 2 and Phase 2 studies, each written for real people, not researchers.
Recruiting studies in California
- NCT05579366RecruitingPhase 1/Phase 2
Study of rinatabart sesutecan for advanced solid tumors
This trial tests an investigational drug called rinatabart sesutecan (also known as Rina-S) for people with advanced solid tumors, including ovarian, endometrial, lung, breast, and other cancers. The drug is designed to target and kill cancer cells, and the study aims to see if it is safe and effective.
Los Angeles, CaliforniaAges 18 years+ - NCT05524584RecruitingPhase 2
Anastrozole, fulvestrant, and abemaciclib for hormone-positive breast cancer
This trial tests whether combining three medicines can better control hormone-receptor–positive, HER2-negative metastatic breast cancer that cannot be cured with surgery or radiation. It may help shrink tumors and slow disease growth compared with standard hormone therapy approaches.
Orange, CaliforniaAges 18 years+ - NCT05491226RecruitingPhase 2
Pembrolizumab plus radiation and myeloid-targeting for high-risk breast cancer
This trial studies whether adding pembrolizumab (an immune “unlocking” drug) to radiation and another treatment that targets certain immune cells can improve outcomes for women with high-risk, early-stage triple negative breast cancer. You may be considered if your cancer has signs that it may respond less to immunotherapy on its own.
Los Angeles, CaliforniaAges 18 years+ - NCT05455619RecruitingPhase 1/Phase 2
Targeted drugs for PI3K-altered, HR+/HER2- breast cancer
This Phase 1/2 trial tests how well a combination of targeted medicines works for advanced or returning HR+/HER2- breast cancer that has a PI3K pathway change (such as PIK3CA, PTEN, or AKT1). It may help by blocking growth signals in the cancer and is especially for people whose cancer has progressed after hormone therapy and a CDK4/6 inhibitor.
Loma Linda, CaliforniaAges 18 years+ - NCT05372640RecruitingPhase 1
Drug combo trial for rare cancers with shared NUT features
This Phase 1 trial tests the safety and early signs of effectiveness of combining two anti-cancer drugs (ZEN003694 and abemaciclib) in teens and adults with metastatic or unresectable NUT carcinoma, breast cancer, and other solid tumors. It may help by finding a safer dose and whether the drug combination can shrink or control tumors that do not respond to standard treatments.
Los Angeles, CaliforniaAges 12 years+ - NCT05377996RecruitingPhase 1/Phase 2
Study drug for advanced solid tumors with tumor tissue testing
This early-stage study tests emiltatug leda-dotin (Emi-Le) in people with advanced or recurring solid cancers. It aims to see how the drug works and how safely it can be given, using tumor tissue testing to help understand who may benefit.
Orange, CaliforniaAges 18 years+ - NCT05366881Recruiting
Blood test study to spot early cancer signal and cancer leftovers
This observational study checks whether a blood test (a “cfDNA” test) can detect early signs of cancer or small amounts of cancer left after treatment. It may help doctors use a simple blood sample to improve cancer detection and follow-up.
Duarte, CaliforniaAges 40 years+ - NCT05334069Recruiting
Blood test study for early cancer detection in patients
This study collects blood from people with cancer and people without cancer (or with possible cancer) to test whether new blood tests can detect cancer earlier. Your blood samples help researchers evaluate how well these tests work.
Arroyo Grande, CaliforniaAges 40–75 - 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.
Los Angeles, CaliforniaAges 18 years+ - NCT05020574RecruitingPhase 2
Study how the microbiome may affect breast implant infections
This Phase 2 study looks at whether changes in the body’s “microbiome” (the normal germs in and on the body) are linked to infections after breast surgery with implants. It may help doctors better predict and prevent implant infections in people undergoing mastectomy with immediate implant placement.
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+ - NCT04585750RecruitingPhase 1/Phase 2
Studying a new drug for cancers with a specific TP53 change
This trial tests a new drug (rezatapopt) for people with advanced cancers that have a specific change in the TP53 gene, called Y220C. The drug is designed to target this change and may slow or stop cancer growth. Some participants may also receive an immunotherapy drug called pembrolizumab (Keytruda).
Irvine, CaliforniaAges 12 years+ - NCT04589468Recruiting
Exercise for cancer survivors at high risk
This study tests whether a structured exercise program can help prevent cancer from coming back in people who have been treated for certain solid tumors (colorectal, ovarian, lung, or breast cancer). If you've completed surgery and adjuvant therapy within the past 2 years and are currently not exercising much, you may be eligible. Participation involves following an exercise plan and regular check-ins.
Durate, CaliforniaAges 18 years+ - NCT04434040RecruitingPhase 2
Atezolizumab and sacituzumab to prevent breast cancer return
This trial tests two medicines after surgery and chemotherapy to help lower the risk that triple-negative breast cancer comes back. It’s for people whose cancer still showed “residual” invasive disease after neoadjuvant (before-surgery) chemotherapy, and whose blood test shows traces of tumor DNA.
San Francisco, 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.
Carmichael, CaliforniaAges 18 years+ - NCT03729115Recruiting
Enhanced breast cancer screening for high-risk women
This study tests a more thorough breast cancer screening program using MRI and other imaging for women at high risk. It aims to detect cancer earlier, which may improve treatment options and outcomes.
Sacramento, CaliforniaAges 25 years+ - NCT03808337RecruitingPhase 2
SBRT radiation plus standard treatment for spread cancer
This trial looks at adding a focused radiation treatment called SBRT to standard care for cancers that have spread to a limited number of spots. It aims to control those spread-out tumors while still using the usual cancer treatment plan.
San Carlos, CaliforniaAges 18 years+ - NCT03606967RecruitingPhase 2
Individualized vaccine added to standard treatment for metastatic triple-negative breast cancer
This Phase 2 trial tests whether adding a personalized cancer vaccine to durvalumab (an immunotherapy), tremelimumab (another immunotherapy), and chemotherapy can improve outcomes for people with metastatic triple-negative breast cancer. It may help your immune system recognize your specific tumor features.
Orange, CaliforniaAges 18 years+ - NCT02620852Recruiting
Wisdom Study: Women’s breast cancer screening decisions
This study looks at how to decide the best breast cancer screening (like mammograms) based on your personal risk. It may help by testing a smarter way to match screening to your risk level.
Sacramento, CaliforniaAges 30–74 - NCT01766297RecruitingPhase 2
Proton radiation after lumpectomy for early breast cancer
This trial studies a type of radiation made with protons to treat only part of the breast after surgery (lumpectomy) for early-stage breast cancer. It may help control the cancer while aiming to reduce radiation to surrounding tissues.
San Diego, CaliforniaAges 50 years+ - NCT01035112Recruiting
MRI check for suspicious breast changes
This study uses a breast MRI scan to look at suspicious areas in the breast. It may help doctors better tell which breast changes need closer follow-up like a biopsy.
Stanford, CaliforniaAges 21 years+ - NCT01042379RecruitingPhase 2
Adaptive drug trial for newly diagnosed breast cancer
This study tests personalized, changing treatment plans (given before surgery) to find better options for your specific breast tumor. You may be asked for extra breast-tissue testing to help match you with the most suitable study drug(s).
Newport Beach, CaliforniaAges 18 years+ - NCT07406087Recruiting
Navigation support for young adults after cancer
This study tests a navigation program to help cancer survivors ages 21-45 get the follow-up care they need. It may be a good fit if you were diagnosed with certain cancers as a teen or young adult.
Pasadena, CaliforniaAges 21–45 - NCT07216105RecruitingPhase 1
New immune cell treatment for advanced solid tumors
This trial tests a new treatment using specially engineered immune cells (called FT836) for people with advanced solid tumors that have not responded to other treatments. It may be given alone or with chemotherapy and/or other antibody medicines. The study aims to see if this approach can shrink tumors or slow their growth.
La Jolla, 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.
- UC San Diego Moores Cancer Center · 4 studies
- University of California, San Francisco · 4 studies
- Providence Medical Foundation - Santa Rosa · 3 studies
- University of California, Davis · 3 studies
- USC Norris Comprehensive Cancer Center · 3 studies
- Bay Area Breast Surgeons Inc · 2 studies
- Bay Area Tumor Institute · 2 studies
- City of Hope · 2 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 244 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.