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, Phase 2 and Phase 3 studies, each written for real people, not researchers.
Recruiting studies in California
- NCT07029399RecruitingPhase 1
Study of NKT5097 for advanced solid tumors
This trial tests an experimental oral drug (NKT5097) for people with advanced solid tumors that have not responded to other treatments. It may also be an option for people with a specific type of breast cancer (HR+/HER2-). The goal is to see if the drug is safe and effective.
Duarte, 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.
Orange, CaliforniaAges 18 years+ - NCT06982521RecruitingPhase 3
Comparing two drug combinations for advanced breast cancer
This trial tests two different combinations of medicines for people with a certain type of advanced breast cancer (HR-positive, HER2-negative) that has a specific gene change called PIK3CA. The goal is to see which combination is better at slowing down the cancer.
Beverly Hills, CaliforniaAges 18 years+ - NCT06954831RecruitingPhase 2
Short-course radiation for early-stage breast cancer
This trial tests a shorter, more intense radiation schedule for people with stage I-III breast cancer after lumpectomy. It aims to find if giving a higher daily dose over fewer sessions is safe and effective.
Lancaster, CaliforniaAges 40 years+ - NCT06943521RecruitingPhase 1/Phase 2
Study of MT-4561 for advanced solid tumors
This trial tests a new drug called MT-4561 in people with advanced solid tumors that have not responded to prior treatments. It aims to see if the drug can help shrink tumors or slow their growth.
Los Angeles, CaliforniaAges 18 years+ - NCT06910761RecruitingPhase 2
Radiation for cancer spread to brain lining
This trial tests whether a precise type of radiation to the brain and spine (craniospinal irradiation) can help control cancer that has spread to the lining of the brain and spinal cord (leptomeningeal disease) in people with breast cancer or non-small cell lung cancer. The goal is to improve symptoms and slow disease progression.
Duarte, CaliforniaAges 18 years+ - NCT06896474Recruiting
Breast cancer treatment choice help for women 70 and older
This study tests a decision aid to help women 70 and older with early stage breast cancer choose their treatment. It looks at whether the tool helps patients and their doctors make a confident treatment choice.
Los Angeles, CaliforniaAges 18 years+ - NCT06876714RecruitingPhase 3
Shorter vs Longer HER2 Therapy for Breast Cancer with Complete Response
This trial compares 6 months versus 12 months of HER2-targeted therapy for people with HER2+ breast cancer who had a complete response after chemo and trastuzumab. The goal is to see if a shorter treatment is just as effective.
Arroyo Grande, CaliforniaAges 18 years+ - NCT06860815RecruitingPhase 2
Cemiplimab with liver radiation for breast cancer that spread to the liver
This trial tests a combination of a drug called cemiplimab (an immunotherapy that helps your immune system fight cancer) and a type of targeted radiation (Y-90 SIR-Spheres) given directly to liver tumors. It is for people with breast cancer that has spread to the liver and who have already had at least one type of chemotherapy.
Duarte, CaliforniaAges 18 years+ - NCT06797635RecruitingPhase 2
Study of Patritumab Deruxtecan and Pembrolizumab for High-Risk Early Breast Cancer
This trial tests a combination of targeted therapies (patritumab deruxtecan plus pembrolizumab) along with other anticancer drugs for people with a high-risk type of early-stage breast cancer that is either triple-negative or has very low hormone receptors and is HER2-negative. The goal is to see if this approach can help prevent the cancer from coming back.
Santa Monica, CaliforniaAges 18 years+ - NCT06790693RecruitingPhase 3
Inavolisib plus hormone therapy for advanced breast cancer
This trial tests a new targeted therapy, inavolisib, combined with standard hormone therapy and a CDK4/6 inhibitor for people with a specific genetic mutation (PIK3CA) in their hormone receptor-positive, HER2-negative advanced breast cancer that has not been treated before. It compares this combination to a placebo plus the same standard treatments.
Burbank, CaliforniaAges 18 years+ - NCT06774027Recruiting
Breast cancer antibody-drug conjugate treatment registry
This study tracks how well antibody-drug conjugates (ADCs) work for breast cancer that has spread. You may join if you are about to start your first or second ADC for hormone receptor-positive/HER2-negative or triple-negative breast cancer.
San Francisco, CaliforniaAges 18 years+ - NCT06780176Recruiting
Breast cancer risk study for people in Florida
This study looks at breast cancer risk factors and outcomes by inviting people who are getting breast biopsies or are new breast patients at certain Florida hospitals to complete a survey. It aims to better understand what affects breast cancer risk and treatment results.
Los Angeles, CaliforniaAges 18 years+ - 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+ - NCT06748222RecruitingPhase 3
Online mindfulness program for breast cancer survivors
This trial tests a 6-week online mindfulness program to help breast cancer survivors manage mild to moderate depression. You may qualify if you finished active treatment within the last 5 years and can use a digital device.
Vacaville, CaliforniaAges 18–50 - NCT06625775RecruitingPhase 1
Study of BBO-10203 for advanced solid tumors
This trial tests a new drug called BBO-10203, alone or combined with other cancer treatments, for people with certain advanced breast, colorectal, or lung cancers. It aims to see if the drug is safe and effective.
Duarte, CaliforniaAges 18 years+ - NCT06586957RecruitingPhase 1
Study of NKT3964 for advanced solid tumors
This trial tests an experimental drug called NKT3964 for people with certain advanced cancers that have stopped responding to standard treatments. It aims to see if the drug can shrink tumors or slow their growth.
Los Angeles, CaliforniaAges 19 years+ - NCT06583395Enrolling by invitation
Meditation retreat study with fitness tracker
This trial studies people attending a 7-day meditation retreat to see how meditation affects well-being. You will wear a fitness tracker and answer surveys.
Palm Desert, CaliforniaAges 21 years+ - 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.
Palo Alto, CaliforniaAges 18–100 - NCT06545331RecruitingPhase 1
A study of XB010 for advanced solid tumors
This trial tests an investigational drug called XB010 for people with solid tumors that have spread or cannot be removed by surgery. It aims to see if XB010 is safe and effective for several cancer types, including lung, breast, head and neck, and esophageal cancers.
Irvine, CaliforniaAges 18 years+ - NCT06533826RecruitingPhase 2
Testing two antibody drugs for HER2-low breast cancer
This trial tests two antibody-drug conjugates (Enhertu and Datroway) for breast cancer that is HER2-low or HER2-0. It aims to find the best treatment sequence for people whose cancer has stopped responding to prior therapy.
San Francisco, 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+ - NCT06445738Recruiting
Can some women safely skip radiation after breast cancer surgery?
This trial is for women 50 and older with early-stage, hormone-positive or HER2-positive breast cancer. It tests whether it is safe to skip radiation therapy after a lumpectomy if an MRI before surgery shows the breast tissue looks a certain way.
San Francisco, CaliforniaAges 50 years+ - 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+
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 · 9 studies
- UC San Diego Moores Cancer Center · 4 studies
- City of Hope Orange County Lennar Foundation Cancer Center · 3 studies
- Kaiser Permanente-Vallejo · 3 studies
- UC San Diego Health · 3 studies
- UCSF Helen Diller Family Comprehensive Cancer Center · 3 studies
- Beverly Hills Cancer Center · 2 studies
- City of Hope at Irvine Lennar · 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.