NCT06590857 · RayzeBio, Inc.
Trial of 225Ac-DOTATATE (RYZ101) in Subjects With ER+, HER2-negative Unresectable or Metastatic Breast Cancer Expressing SSTRs.
(TRACY-1)
What this study is about
Phase 1b/2 where both patients and doctors know the treatment given trial of 225Ac-DOTATATE (RYZ101) in subjects with ER+, HER2-negative unresectable or metastatic breast cancer expressing SSTRs.
View original scientific description
Phase 1b/2 open-label trial of 225Ac-DOTATATE (RYZ101) in subjects with ER+, HER2-negative unresectable or metastatic breast cancer expressing SSTRs.
Interventions
DRUG
RYZ101
Ac-225
DRUG
Standard of Care Endocrine Therapy
Investigator's choice of endocrine therapy, such as, anastrozole, elacestrant, exemestane, fulvestrant, imlunestrant, letrozole, tamoxifen, or vepdegestrant
Primary outcome measures
Dose Escalation
Time frame: 6 weeks of RYZ101 treatment
Incidence rate of DLTs during the first 6 weeks of RYZ101 treatment
Endocrine Therapy Combination Dose Escalation
Time frame: [Time Frame: 6 weeks of study treatment]
Incidence rate of DLTs during the first 6 weeks of study treatment
Endocrine Therapy Combination Dose Escalation
Time frame: Up to approximately 5 years after the last subject has completed RYZ101 treatment
Incidence and severity of treatment emergent AEs by NCI-CTCAE v5.0
Endocrine Therapy Combination Dose Escalation and Expansion
Time frame: Up to approximately 5 years after the last subject has completed RYZ101 treatment
Progression Free Survival, defined as the time between first dose of study treatment and progression or death, as assessed by the investigator per RECIST v1.1 criteria
Endocrine Therapy Combination Dose Escalation and Expansion
Time frame: Up to approximately 5 years after the last subject has completed RYZ101 treatment
Time from the first dose of study treatment to first occurrence of Skeletal Related Events
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Subjects must meet all the following criteria for enrollment in the study:
- Eastern Cooperative Oncology Group performance status ≤2.
- Histologically confirmed, ER+, HER2-negative, locally advanced and unresectable or metastatic breast cancer not amenable to treatment with curative intent.
- At least one RECIST v1.1-measurable tumor lesion that is SSTR-PET positive (defined as maximum standard uptake value (SUVmax) higher than liver mean standard uptake value (SUVmean) on SSTR-PET imaging) and at least 80% of RECIST v1.1measurable tumor lesions are SSTR-PET positive
- Sufficient renal function, as evidenced by eGFR ≥60 mL/min/1.73m2 calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation
- Adequate hematologic and hepatic function
Exclusion criteria
- Subjects who meet any of the following criteria will be excluded from the study:
- Prior radiopharmaceutical therapy, including radioembolization.
- Any toxicities from prior treat
Where
- Phoenix, Arizona
- Irvine, California
- San Diego, California
- Santa Monica, California
- Longmont, Colorado
- Jacksonville, Florida
- Atlanta, Georgia
- Indianapolis, Indiana
- Boston, Massachusetts
- Detroit, Michigan
- Rochester, Minnesota
- St Louis, Missouri
And 12 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Aug 24, 2026 · Source of record for eligibility and locations