Phase 1 Study of CLR 125 in Triple Negative Breast Cancer
This study is testing CLR 125, an investigational radiopharmaceutical (a drug that uses a small amount of radioactive material), for people with advanced triple negative breast cancer. You might be able to join if you are 18 or older, have triple negative breast cancer that has progressed after at least one prior treatment, and meet other specific criteria. The main goals are to find the best dose of CLR 125 for future studies and to understand its side effects. Researchers will also look at how well CLR 125 works against the cancer. Some participants may also receive Iopofosine I 131 to see how much radiation reaches different organs and the tumor. Up to 60 people are expected to participate.
- Study design
- This is an interventional study with a planned enrollment of 60 participants. It aims to determine the recommended dose and regimen for CLR 125.
- What's involved
- You will receive CLR 125 intravenously (into a vein) 4 times each cycle, with cycles repeated every 8 weeks. You will visit the clinic once every 3 weeks for checkups and testing, and report any side effects or new medications.
- Compensation
- Not stated in the trial record.
- Follow-up
- Adverse events related to CLR 125 will be assessed throughout the study through 1 year following completion of treatment.
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NCT07311993
Phase 1 Study of CLR 125 in Triple Negative Breast Cancer
Recruiting
PHASE1Ages 18+InterventionalTreatmentCellectar Biosciences, Inc.
~60 participants
Updated 2026-06-03 on ClinicalTrials.gov
What's tested:Iopofosine I 131CLR 125
At a glance
Recruiting sites
4 of 4 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Dose Determination for CLR 125
Measured over 57 days after initiation of last cycle (each cycle is 57 days)
+1 more outcome measured
Conditions
Where it's being run
4 sites across 4 statesFlorida1
Maryland1
Minnesota1
New Jersey1
Study leadership
- Jarrod Longcor · STUDY_DIRECTOR · Cellectar Biosciences
Who to contact
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Do you actually qualify for this trial?
Add a private profile and we'll compare every criterion below against your situation — and tell you which ones are met, uncertain, or excluding.
Eligibility criteria
Inclusion
Unequivocal TNBC histology \[ER and PR less than 10% each and HER-2 negative\].
Patients that have progressed after at least one prior standard therapeutic regimen given alone or in combination (including, but not limited, to: chemotherapy, immunotherapy, sacituzumab govitecan-hziy, trastuzumab deruxtecan).
Patients who have received neo-adjuvant or adjuvant therapy must be at least one year from that treatment regimen.
Patient is ≥ 18 years of age.
ECOG performance status of 0 to 2.
Life expectancy ≥ 6 months.
Patient must meet the following laboratory criteria:
Platelets ≥ 75,000/uL \[75 x 10\^9/L\]
White blood cell (WBC) count ≥ 3000/uL
Absolute neutrophil count ≥ 1500/uL
Hemoglobin ≥ 9 g/dL
Estimated glomerular filtration rate ≥ 30 mL/min/1.73 m2 (as reported by the local lab)
Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 × upper limit of normal (ULN)
Bilirubin \< 1.5 × ULN
At least one measurable lesion, as defined by RECIST v1.1, with longest diameter at baseline ≥ 10 mm (excluding lymph nodes, for which the short diameter must be ≥ 15 mm).
Patients with known brain metastases must have completed any radiotherapy or systemic treatments for brain metastases prior to enrollment; by investigator assessment be considered stable with no new signs or symptoms for at least 1 month, and on a stable dose of steroids (unchanged for three weeks prior to registration or on a steroid tapering regimen).
Patients must express willingness and ability to comply with scheduled study visits, treatment plans, laboratory tests, and other study procedures.
Patient or their legally authorized representative must have the ability to understand and provide signed informed written consent before the initiation of any study-related procedures.
Female patients of childbearing potential must have a negative pregnancy test within 24 hours of dosing.
Women of childbearing potential must agree to use a highly effective method of contraception during the study and for 12 months following administration of the study drug. Highly effective methods of contraception include combined (estrogen and progestogen containing) hormonal contraceptives associated with inhibition of ovulation, progestogen-only hormonal contraception associated with inhibition of ovulation, intrauterine device, intrauterine hormone-releasing system, vasectomized partner, or sexual abstinence. Women who have undergone hysterectomy, bilateral oophorectomy, or bilateral tubal ligation, or are post-menopausal (no menses for 12 months without an alternative medical cause) are considered to be of non-childbearing potential.
Men who are able to father a child must agree to use a condom during the study and for 12 months following administration of the study drug.
Exclusion
Antitumor systemic therapy or investigational therapy, within three-half-lives of the agent preceding study drug administration. NOTE: Patients participating in non-interventional clinical trials (i.e., non-drug) are allowed to participate in this trial.
Focal radiation (including palliative radiation) to non-target lesions should be completed at least 2 weeks prior to dosing.
For patients receiving CLR 125 after participation in the dosimetry phase, CLR 131 washout is not required prior to dosing with CLR 125.
Prior targeted radiotherapy.
Prior external beam radiation therapy resulting in greater than 20% of total bone marrow receiving greater than 20 Gy. For estimation purposes, the following bone marrow percentages can be used:
Vertebral bodies: Cervical 0.5%, thoracic 1%, lumbar 2% per vertebral body
Hemipelvis (ilium, acetabulum, ischium): 13% per side
Sacrum: 10%
Skull: 12%
Scapula: 5% per side
Ribs: 4% per side
Femur: 3% per side
Ongoing Grade 2 or greater toxicities due to previous therapies, excluding alopecia, that in the opinion of investigator might be exacerbated by study treatment.
Patients with prior or concurrent malignancy other than TNBC with the following exceptions, which must be fully treated with no evidence of disease for at least 2 years: non-melanoma skin cancers only requiring topical treatment or surgical excision; melanoma in situ; treated cervical carcinoma in situ; successfully treated prostate cancer.
Any other concomitant serious illness or organ system dysfunction (including cardiac and pulmonary dysfunction) that in the opinion of the Investigator would either compromise patient safety or interfere with the evaluation of the safety of the test drug.
Known history of human immunodeficiency virus or uncontrolled, serious, active infection.
Pregnancy or breast-feeding
What this trial measures
- Dose Determination for CLR 12557 days after initiation of last cycle (each cycle is 57 days)
Identify the recommended Phase 2 dose and regimen of CLR 125 in advanced TNBC patients
- Number of adverse events related to study treatment (CLR 125)Assessed throughout the study through 1 year following completion of treatment.
Adverse Events are graded per NCI CTCAE v5.0