Clinical trials · California
Breast cancer clinical trials in California
We’re tracking 239 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
- NCT06562192RecruitingPhase 1
Testing a radioactive drug for advanced pancreatic, lung, breast, and colorectal cancers
This trial tests a new radioactive drug (177Lu-NNS309) for people with advanced pancreatic, lung, breast, or colorectal cancer that has not responded to prior treatments. It aims to see if the drug can target and shrink tumors.
Los Angeles, CaliforniaAges 18–100 - NCT06369285RecruitingPhase 2
Alisertib and hormone therapy for advanced breast cancer
This trial tests a new drug, alisertib, combined with hormone therapy for people with HR-positive, HER2-negative breast cancer that has spread or come back and is no longer curable. It may be an option if you've already tried at least two hormone therapies and a CDK4/6 inhibitor.
Beverly Hills, CaliforniaAges 18 years+ - NCT07318805RecruitingPhase 1
A study of PF-08032562 for advanced solid tumors
This study tests a new medicine, PF-08032562, for people with advanced breast or colorectal cancer that has not responded to prior treatments. It aims to see if the drug is safe and can help shrink or slow the cancer.
Duarte, CaliforniaAges 18 years+ - NCT06827236RecruitingPhase 1/Phase 2
Testing a new combination treatment for advanced breast cancer
This study tests two experimental drugs, BNT323 and BNT327, together in people with advanced breast cancer. The goal is to find the best dose and see if the combination is safe and helpful.
Beverly Hills, CaliforniaAges 18 years+ - NCT06293898RecruitingPhase 1
Study of BL-M07D1 for HER2-positive solid tumors
This trial tests a new drug, BL-M07D1, for people with advanced solid tumors that have a protein called HER2. It is for patients who have already tried at least two other standard treatments.
Duarte, 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+ - 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+ - 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+ - NCT03452774Recruiting
AI matches your cancer tests to possible treatment trials
This trial uses an AI system to help match people with certain cancer types and specific tumor test results (like gene or protein markers) to relevant clinical trials. It may help you and your doctor find studies that fit your cancer biology faster.
Duarte, CaliforniaAges Any age - 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+ - 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+ - NCT04305834RecruitingPhase 2
Abemaciclib plus hormone pills for metastatic breast cancer in older adults
This Phase 2 study tests whether abemaciclib combined with standard hormone (endocrine) therapy can better control metastatic breast cancer in people age 70 and older. It may help if your cancer has already grown despite prior hormone therapy and/or other cancer medicines.
South Pasadena, CaliforniaAges 70 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+ - NCT04553770RecruitingPhase 2
Trastuzumab deruxtecan with or without anastrozole for early breast cancer
This Phase 2 study tests whether trastuzumab deruxtecan alone or combined with anastrozole can control early-stage breast cancer that is HER2-low and hormone-receptor positive. It aims to improve outcomes after initial surgical treatment by targeting cancer cells that may have low levels of HER2.
Torrance, CaliforniaAges 18 years+ - NCT04585750RecruitingPhase 1/Phase 2
Study drug for TP53 Y220C-mutated advanced cancers
This early-phase study tests PC14586 (rezatapopt) in people with advanced or metastatic solid cancers that carry a specific TP53 mutation called Y220C. It mainly looks at safety and how well the treatment may work, sometimes combined with pembrolizumab.
Irvine, CaliforniaAges 12 years+ - NCT04603209Recruiting
Check-in registry for radiation during breast-conserving surgery
This registry study tracks people with early-stage, single-area breast cancer to understand outcomes when radiation is given during breast-conserving surgery. It may help doctors improve treatment planning for patients like you.
Santa Monica, 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+ - NCT05216432RecruitingPhase 1
RLY-2608 for PIK3CA-mutant advanced solid tumors and breast cancer
This early study (Phase 1) tests RLY-2608, a targeted cancer drug for tumors with a PIK3CA mutation. It studies the drug alone and combined with hormone therapy (and sometimes CDK4/6 or CDK4 medicines) to see safety, dose, and whether it can shrink tumors.
San Diego, 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+ - 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+ - 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.
Newport, 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+ - NCT05508906RecruitingPhase 1
Test drug OP-1250 with other medicines in ER-positive breast cancer
This Phase 1b study tests OP-1250 (palazestrant) combined with other targeted medicines for ER-positive, HER2-negative advanced or metastatic breast cancer. It mainly looks at safety and correct dosing, but may also help shrink tumors or slow growth.
San Francisco, 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+
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 · 4 studies
- University of California, San Francisco · 4 studies
- Beverly Hills Cancer Center · 2 studies
- Cancer and Blood Specialty Clinic · 2 studies
- Cedars-Sinai Medical Center · 2 studies
- City of Hope Orange County Lennar Foundation Cancer Center · 2 studies
- Hoag Memorial Hospital Presbyterian · 2 studies
- MemorialCare Orange Coast Medical Center · 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 239 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.