CTO-R10602-101

Cohort 1 will consist of twelve patients with metastatic or locoregionally recurrent, endocrine-resistant disease, who have received at least one and no more than two prior lines of chemotherapy or ADC. Three dose levels will be evaluated, with each patient receiving a single dose, followed by imaging at five timepoints and blood dosimetry at seven timepoints.

In Cohort 2, ten patients will receive a single dose determined based on the results from Cohort 1. These patients will undergo imaging at a single timepoint, also selected based on findings from Cohort 1, and no dosimetry will be performed.

Inclusion Criteria:

1. Breast Cancer Eligibility:

Cohort 1: pathologically confirmed estrogen and/or progesterone receptor (ER/PR) positive locoregionally recurrent or metastatic breast cancer that is refractory to endocrine therapy (progression on at least one line of endocrine therapy and determined by the investigator that Participant would not benefit from additional endocrine therapy) who have received at least one and no more than two lines of chemotherapy or antibody drug conjugate in the metastatic setting (recurrence within 6 months of adjuvant chemotherapy counts as one line of therapy). There is no limit on prior number of lines of endocrine therapy, prior treatment with CDK4/6, AKT, PIK3CA and/or mTOR inhibitors is permitted.

Cohort 2: pathologically confirmed ER positive/HER2 negative locoregional or metastatic breast adenocarcinoma that is not amenable to resection, with progression on at least one line of prior endocrine therapy in the adjuvant or metastatic setting, and starting next line of therapy that will include tamoxifen, fulvestrant, aromatase inhibitor, or elacestrant with or without ovarian suppression. Study Participants who will receive combination therapy (with alpelisib, capiversitib, everolimus or a CDK4/6 inhibitor) as their next line of treatment must be imaged while receiving only single agent endocrine therapy, and before starting the targeted therapy. Targeted therapy can be started after imaging.
2. At least one measurable target lesion per RECIST 1.1 criteria within 42 days of dosing with 68Ga-R10602.
3. Male or non-pregnant, non-lactating female Study Participant age ≥18 years. Female Study Participant of childbearing potential and male Study Participant (if sexually active) must agree to use adequate method(s) of effective contraception during their participation in the study.
4. Eastern Cooperative Oncology Group (ECOG) Performance Status ≤2.
5. Adequate hepatic function (within 28 days of dosing with 68Ga-R10602)
6. Adequate renal function determined within 28 days of dosing with 68GaR10602.
7. Able to understand and willing to sign an informed consent form.

Exclusion Criteria:

1. Received a radionuclide within a period of less than 10 physical half-lives of the administered radionuclide prior to dosing with 68Ga-R10602.
2. Radiotherapy ≤14 days prior to dosing with 68Ga-R10602.
3. Major surgery ≤21 days prior to dosing with 68Ga-R10602 or has not recovered from adverse effects of such procedure.
4. Severe or unstable medical condition, such as congestive heart failure (New York Heart Association \[NYHA\] Class III or IV), ischemic heart disease, uncontrolled hypertension, uncontrolled diabetes mellitus, as well as an uncontrolled cardiac arrhythmia requiring medication (≥Grade 2, according to NCI-CTCAE, Version 5.0), myocardial infarction within 6 months prior to starting Investigational Product, or any other significant or unstable concurrent cardiac illness. Note: Stable chronic atrial fibrillation is allowed.
5. History of cerebrovascular accident within 6 months or that resulted in ongoing neurologic instability.
6. Major active infection requiring antibiotics.
7. Known active human immunodeficiency virus infection or active infection with Hepatitis B or C.
8. Acute illness within 14 days prior to dosing with 68GaR10602 unless mild in severity, as assessed by the Investigator.
9. Any other condition that in the opinion of the Investigator would place the Study Participant at an unacceptable risk or cause the Study Participant to be unlikely to fully participate or comply with study procedures.

Breast

Indiana University (IU)

• IU Health Methodist Hospital
• IU Health North/ Schwarz Cancer Center
• Indiana University Hospital / IU Simon Cancer Center