68Ga-R11228 PET imaging and 177Lu-R11228 targeted radiotherapy for hormone-receptor positive breast cancer

Phase 1 Study of 68Ga-R11228 and 177Lu-R11228 in Patients With Advanced Breast Cancer

Phase 1 Interventional Radionetics Oncology · NCT07121244

This test uses a PET imaging agent (68Ga-R11228) to find ER+/PR+ HER2− breast cancer lesions and, for people with positive scans, gives a matching radioligand therapy (177Lu-R11228) to try to treat them.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment62 (estimated)
Ages18 Years and up
SexAll
SponsorRadionetics Oncology Industry-sponsored
Drugs / interventionschemotherapy
Locations7 sites (Indianapolis, Indiana and 6 other locations)
Trial IDNCT07121244 on ClinicalTrials.gov

What this trial studies

This Phase 1 study first gives single doses of the PET agent 68Ga-R11228 (Part A) to determine safe dosing and how well it visualizes ER/PR+ HER2− recurrent or metastatic breast cancer lesions. In Part B, patients with PET-positive lesions may receive multiple doses of the therapeutic radioligand 177Lu-R11228 over about 36 weeks with dose escalation to define safety and tolerability. Part B requires endocrine-refractory disease and prior or declined chemotherapy/antibody-drug conjugate in the metastatic setting. A long-term follow-up period of up to 5 years begins after completion of the last 177Lu-R11228 dose.

Who should consider this trial

Good fit: Adults (≥18) with pathologically confirmed ER and/or PR positive, HER2-negative locoregionally recurrent or metastatic breast cancer are eligible for Part A, and Part B is for those with endocrine-refractory disease who have at least one PET-positive lesion and have received or declined prior chemotherapy/ADC.

Not a fit: Patients whose tumors do not take up the 68Ga-R11228 tracer on PET, those with HER2-positive disease, pregnant or breastfeeding individuals, or patients with early-stage non-metastatic disease are unlikely to benefit from the investigational therapy.

Why it matters

Potential benefit: If successful, this approach could enable more precise detection and deliver targeted radioligand therapy to shrink tumors while limiting exposure to normal tissues in endocrine-resistant HR+ breast cancer.

How similar studies have performed: Radioligand therapies using 177Lu have shown meaningful results in other cancers (for example PSMA-targeted prostate cancer), but using 68Ga/177Lu agents specifically in hormone-receptor positive breast cancer is a novel application with limited prior clinical data.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

Part A

* Pathologically confirmed estrogen and/or progesterone receptor (ER/PR) positive and HER2 negative locoregionally recurrent or metastatic breast cancer
* At least one target or non-target lesion per RECIST v1.1 criteria.
* Male or non-pregnant, non-lactating female subjects age ≥18 years.

Part B

* Pathologically confirmed estrogen and/or progesterone receptor (ER/PR) positive and HER2 negative locoregionally recurrent or metastatic breast cancer
* Refractory to endocrine therapy. Note: there is no limit on prior number of lines of endocrine therapy or prior treatments with CDK4/6, AKT, PI3K and/or mTOR inhibitors.
* Received or declined at least one line of chemotherapy or antibody drug conjugate in the locoregionally recurrent or metastatic setting
* Progressive disease or intolerance to last treatment.
* At least one target lesion per RECIST v1.1 criteria.
* Male or non-pregnant, non-lactating female subjects age ≥18 years.
* Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1.
* Life expectancy of at least six months.
* Adequate bone marrow reserve, hepatic function and renal function.

Exclusion Criteria:

Part A

* Study participant has not recovered from clinically significant adverse event(s) resulting from most recent anticancer therapy/intervention.
* Known central nervous system (CNS) disease, except for those subjects with treated brain metastasis who are stable for at least 1 month, having no evidence of progression or hemorrhage after treatment and no ongoing requirement for corticosteroids, as ascertained by clinical examination and brain imaging (magnetic resonance imaging \[MRI\] or computed tomography \[CT\]) during the screening period.
* Radiotherapy for breast cancer ≤ 28 days prior
* Received a radionuclide within a period of less than 10 physical half-lives of the administered radionuclide prior to dosing with 68Ga-R11228.
* Any condition that precludes the proper performance of imaging procedures required in this study.

Part B

* Study participant has not recovered from clinically significant adverse event(s) resulting from most recent anticancer therapy/intervention
* Treatment with anticancer therapy or with an investigational drug or device within 21 days or 5 half-lives of the agent (whichever is shorter)
* Known central nervous system (CNS) disease, except for those subjects with treated brain metastasis who are stable for at least 1 month, having no evidence of progression or hemorrhage after treatment and no ongoing requirement for corticosteroids, as ascertained by clinical examination and brain imaging (magnetic resonance imaging \[MRI\] or computed tomography \[CT\]) during the screening period.
* Radiotherapy for breast cancer ≤ 28 days
* Prior systemic radionuclide therapeutic treatment.
* Received a radionuclide within a period of less than 10 physical half-lives of the administered radionuclide prior to dosing with 68Ga-R11228.
* Any unresolved NCI-CTCAE Version 5.0 Grade 2 or higher toxicity (except alopecia and Grade 2 platinum-therapy related neuropathy) from previous breast cancer treatment and/or from medical/surgical procedures or interventions.
* Any condition that precludes the proper performance of imaging procedures required in this study.

Where this trial is running

Indianapolis, Indiana and 6 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Locoregionally Recurrent Hormone-receptor Positive Breast CancerMetastatic Hormone Receptor Positive Breast CancerHormone Receptor Positive Breast CancerEndocrine resistantRadioisotope
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.