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RecruitingLast updated: 10 October 2025

This study is recruiting people with recurrent or metastatic breast cancer that is HER2- and ER+ and/or PR+ to evaluate a new targeted product which may make it easier to detect cancer in PET scansPhase 1 Study of 68Ga-R11228 and 177Lu-R11228 in Patients With Advanced Breast Cancer

Trial purpose

Medical clipboardDiagnostic

Tumor type

Breast Cancers Breast

Age

People18+

Clinical summary

Summary

This study has two parts. Currently only Part A is available, and Part B will be avilable in 2026.

Part A is being conducted to test 68Ga-R11228, which is a new investigational product that has been designed to detect cancer lesions in the body and make them visible on a PET scan.

Three dose levels of 68Ga-R11228 will be evaluated, with each participant receiving a single dose as an injection.

Part B is being conducted to test 68Ga-R11228 and additionally 177Lu-R11228, which has been designed to treat people who have cancer lesions with positive uptake on PET scan when using 68Ga-R11228.

Participants who qualify for 177Lu-R11228 treatment will receive up to 6 doses over approximately 36 weeks. Multiple 177Lu-R11228 dose levels will be evaluated in Part B, and this will also be administered as an injection.

A 5-year follow-up period begins once the last cycle of 177Lu-R11228 dosing is completed. 

Conditions

This trial is treating people with recurrent or metastatic breast cancer that is HER2- and ER+ and/or PR+

Eligibility

Inclusion

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

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.

Inclusion

  • You have had treatment, but your cancer has come back (relapsed or recurrent).
  • Your cancer has spread to other parts of the body (metastatic) or has grown into nearby parts of the body (locally advanced).

Exclusion

  • You have certain types of non-cancer medical conditions.
  • You have had certain treatments, surgical procedures or drugs.
Message

Clinical trials have complex eligibility criteria, and other criteria may apply for this trial. Ask your doctor about whether this trial could be right for you.

Participating hospitals

Recruiting hospitals

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More information

Trial Identifiers

Information on this page is partially produced from ClinicalTrials.gov *. View further details about this trial on the registry via the links below:

Trial sponsor

Radionetics Oncology

Scientific Title

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

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