Clinical trials · California
Breast cancer clinical trials in California
We’re tracking 237 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
- NCT05579366RecruitingPhase 1/Phase 2
Study drug for advanced ovarian and other solid cancers
This Phase 1/2 trial studies Rinatabart Sesutecan to treat advanced cancers, with special focus on certain ovarian cancer types. It’s meant for people whose cancer has come back or has not responded to prior treatments.
Los Angeles, CaliforniaAges 18 years+ - NCT05774951RecruitingPhase 3
Camizestrant for hormone-positive, HER2-negative early breast cancer
This trial tests camizestrant, a medicine that blocks estrogen signaling, to help prevent hormone-positive, HER2-negative early breast cancer from coming back. You may be eligible if your cancer has higher- or intermediate-risk features and you already completed at least 2 years of hormone therapy.
Anaheim, CaliforniaAges 18–130 - NCT05902507Recruiting
MRI guidance during breast cancer radiation treatment
This trial studies using MRI images to help plan and guide radiation therapy after breast-conserving surgery. It may help doctors target the right area more accurately while keeping treatment standard and safe.
San Francisco, CaliforniaAges 18 years+ - NCT05964504Recruiting
Registry study for metastatic lobular breast cancer
This study collects health information from adults with invasive lobular breast cancer that has spread (metastatic) to help researchers understand factors linked to survival. Joining may help build better knowledge for future treatments and care planning.
San Francisco, CaliforniaAges 18 years+ - NCT05983432RecruitingPhase 1
Study of BL-B01D1 for advanced lung and other solid tumors
This trial tests an experimental drug called BL-B01D1 for people with several types of advanced solid tumors, especially non-small cell lung cancer and breast cancer. It's designed for those whose cancer has continued to grow after standard treatments.
Orange, CaliforniaAges 18 years+ - NCT06072612RecruitingPhase 3
Bria-IMT plus CPI vs standard care for advanced breast cancer
This trial tests a new combination of two immunotherapy drugs (Bria-IMT and a checkpoint inhibitor) against your doctor's choice of standard treatments. It is for people with advanced breast cancer that has spread and who have already tried several prior therapies.
Santa Monica, CaliforniaAges 18 years+ - NCT06075810RecruitingPhase 1
Oral MBQ-167 for advanced breast cancer
This trial tests an experimental oral drug, MBQ-167, for people with advanced breast cancer who have tried other treatments or have no standard options left. The goal is to see if the drug can help slow or stop the cancer.
Beverly Hills, CaliforniaAges 21 years+ - NCT06092892RecruitingPhase 2
Upfront targeted lymph node removal for early breast cancer
This trial is for women age 45 and older with early ER-positive breast cancer that has spread to the lymph nodes under the arm. It tests a surgery approach where the main tumor and only a few key lymph nodes (rather than many) are removed.
Los Angeles, CaliforniaAges 45 years+ - NCT06099769RecruitingPhase 2
Testing enzalutamide with or without mifepristone for AR-positive breast cancer
This trial tests if adding the drug mifepristone to the standard antiandrogen enzalutamide works better than enzalutamide alone or chemotherapy for people with a specific type of breast cancer that has androgen receptors. It aims to find a new targeted treatment option for triple-negative or ER-low breast cancer.
San Francisco, CaliforniaAges 18 years+ - NCT06112613Recruiting
Mobile health to help with breast cancer pill-taking
This study uses text messages to help people with metastatic breast cancer remember to take their daily pills and asks about any missed doses. It aims to improve how well patients stick to their CDK4/6 inhibitor medication.
Orange, CaliforniaAges 18 years+ - NCT06224673RecruitingPhase 2
Testing ARX788 for HER2-low advanced breast cancer
This trial tests a new drug, ARX788, for people with HER2-low breast cancer that has spread or cannot be removed by surgery. The goal is to see if ARX788 helps shrink or control the cancer.
San Francisco, CaliforniaAges 18 years+ - NCT06253871RecruitingPhase 1
Study of IAM1363 for HER2 Cancers
This trial tests a new oral drug called IAM1363 for people with HER2-altered cancers that have stopped responding to previous treatments. The goal is to see if the drug is safe and how well it works against these cancers.
La Jolla, CaliforniaAges 18 years+ - NCT06268665RecruitingPhase 2
Tart Cherry Juice for Preventing Nerve Damage from Chemotherapy
This study tests whether tart cherry juice can help prevent nerve damage (peripheral neuropathy) caused by the chemotherapy drug paclitaxel. Participants drink tart cherry juice daily during their 12 weeks of paclitaxel treatment.
Sacramento, CaliforniaAges 18 years+ - NCT06297265Recruiting
Gentle breast massage after lumpectomy for breast cancer
This trial studies whether a special gentle massage technique (manual lymphatic drainage) can help women who have had breast-conserving surgery and will receive whole breast radiation. The goal is to see if it reduces side effects and improves recovery.
Los Angeles, 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+ - NCT06471673RecruitingPhase 1/Phase 2
BRIA-OTS cellular immunotherapy for metastatic breast cancer
This study tests an investigational cellular immunotherapy called BRIA-OTS for people with metastatic breast cancer that has spread and is no longer responding to standard treatments. It aims to help the immune system fight cancer cells.
Santa Monica, 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+ - 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+ - 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+ - NCT06568692RecruitingPhase 2
Study of PCS6422 with capecitabine for advanced breast cancer
This trial tests a new drug combination (PCS6422 plus capecitabine) for people with advanced or metastatic breast cancer that has not responded to other treatments. The goal is to see if adding PCS6422 can make the chemotherapy work better.
Oxnard, CaliforniaAges 18 years+ - NCT06586957RecruitingPhase 1
Study of NKT3964 for advanced solid tumors
This trial is testing an experimental oral drug called NKT3964 for people with advanced solid tumors that have stopped responding to standard treatments. The drug works by blocking a protein called CDK2, which some cancers need to grow.
San Francisco, CaliforniaAges 18 years+ - 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.
Los Angeles, CaliforniaAges 18 years+ - NCT05941520RecruitingPhase 2
Acolbifene vs low-dose tamoxifen to prevent breast cancer
This Phase 2 trial compares acolbifene and low-dose tamoxifen to see which better lowers breast cancer risk in premenopausal women at high risk. You would be followed with health visits, blood tests, and a breast tissue sampling procedure.
Duarte, CaliforniaAges 35 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+
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.
- University of California, San Francisco · 8 studies
- University of California, Los Angeles (UCLA) · 5 studies
- University of California San Diego · 4 studies
- City of Hope Comprehensive Cancer Center · 3 studies
- Cedars-Sinai Medical Center · 2 studies
- University of California, Irvine Medical Center / UC Irvine Health · 2 studies
- USC / Norris Comprehensive Cancer Center · 2 studies
- Bass Medical Group
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 237 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.