Testing the Safety of the Anti-cancer Drug, Sn-117m-DTPA, for Advanced Cancers That Have Spread to Bones

Starting soon · Phase 1

Conditions studied: Anatomic Stage IV Breast Cancer AJCC v8, Metastatic Breast Carcinoma, Metastatic Lung Non-Small Cell Carcinoma, Metastatic Malignant Neoplasm in the Bone, Metastatic Prostate Adenocarcinoma, Stage IV Lung Cancer AJCC v8, Stage IVB Prostate Cancer AJCC v8

In brief

This phase I trial tests the safety, side effects and best dose of tin (Sn)-177m-diethylenetriaminepentaacetic acid (DTPA) and how well it works in treating prostate, breast or non-small cell lung cancer that has spread from where it first started (primary site) to the bones (bone metastases). Sn-117m-DTPA was originally tested in tumors that had spread to the bones to help reduce bone pain. The drug has been improved and is designed to send low-level radiation to tumors in the bone while being gentler on the bone marrow, where blood cells are made. Sn-117m-DTPA may be safe and tolerable, and may slow down or shrink tumors in patients with metastatic prostate, breast, or non-small cell lung cancer that has spread to the bones.

Key facts

Study ID

NCT06982222

Run by

National Cancer Institute (NCI)

People needed

24

Starts

2026-10-01

Expected to finish

2027-02-12

Last updated by the study team

2026-05-13

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• Histologically documented prostate, breast, or non-small cell lung cancer (NSCLC)
• Metastatic disease in bone only (patients with visceral disease, cutaneous disease or malignant lymph nodes > 3 cm in largest diameter are not eligible)
• Documented disease progression (1 or more new bone lesion or enlargement of existing bone lesion, identified by Tc-99m bone scintigraphy or CT scan, magnetic resonance imaging [MRI], fludeoxyglucose F-18 [FDG] PET CT scan or PSMA PET CT scan)
• Must have progression on at least one line of standard of care systemic therapy. There are no maximum number of prior therapies
• Patients with prostate cancer
• Patients with prostate adenocarcinoma, their disease must be characterized as: must have prior bilateral orchiectomy or ongoing androgen-deprivation therapy and a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L)
• Serum PSA progression, defined as two consecutive increases in PSA over a previous reference value, each measurement at least one week apart or, PSA progression ≥ 25% after 12 weeks of current standard of care (SOC) therapy (Scher et al., 2016)
• Patients must have a baseline positive PSMA-PET scan. Patients must have progressed on at least one line of hormone therapy: Androgen receptor signaling inhibitors (ARSIs) therapy such as enzalutamide, apalutamide, darolutamide, or androgen synthesis blockers (abiraterone acetate). There are no minimum number of prior hormone therapies
• Progression after chemotherapy (docetaxel or cabazitaxel) in patients who were chemotherapy candidates is allowed. However, prior chemotherapy is not required
• Progression after a prostate-specific membrane antigen (PSMA)-targeted radiopharmaceutical therapy (for example: lutetium-177 vipivotide tetraxetan [Pluvicto]) is allowed but not required
• Allowed to have received one prior cytotoxic chemotherapy treatment and one radiopharmaceutical therapy treatment OR no more than two cytotoxic chemotherapy treatments (for patients who have not received a prior radiopharmaceutical therapy treatment)
• Patients with breast cancer
• Patients with any estrogen receptor (ER)/progesterone receptor (PR)/human epidermal growth factor receptor 2 (HER2) receptor status are eligible
• Patients with hormone-receptor positive disease should have progressed on at least one or more prior line(s) of SOC anti-estrogen therapy and a cyclin-dependent kinase (CDK)4/6 inhibitor (except if patient had a contraindication or intolerable toxicity with the use of these agents)
• Patients with HER2 positive disease should have progressed on at least one or more line(s) of SOC anti-HER2 therapy.
• Patients with triple negative disease should have progressed on at least one more line(s) of SOC chemotherapy
• Previous radiation and chemotherapy are allowed
• Patients with non-small cell lung cancer (NSCLC)
• Patients with NSCLC should have progressed on at least one or more prior line(s) of SOC therapy, including chemotherapy and/or immunotherapy or targeted therapy if they qualify
• Age ≥ 18 years. Because no dosing or adverse event data are currently available on the use of Sn-117m-DTPA in patients < 18 years of age, children are excluded from this study
• Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 (Karnofsky ≥ 60%)
• Absolute neutrophil count ≥ 1,000/mcL
• Platelets ≥ 75,000/mcL
• Hemoglobin > 9 g/dL
• Total bilirubin ≤ 2.5 x institutional upper limit of normal (ULN)

You may not qualify if…

• Patients who have not recovered from reversible adverse events due to prior anti-cancer therapy (i.e., have residual toxicities > grade 1) with the exception of alopecia
• Patients must not have received any investigational agents within 4 weeks or 5 half-lives, whichever is shorter, before starting study treatment, nor be scheduled to receive one during the planned treatment period
• Patients must not have a history of allergic reactions attributed to compounds of similar chemical or biologic composition to Sn-117m-DTPA
• Patients must not have imminent or established spinal cord compression, pathological fracture in weight bearing bones, or bone lesion with soft tissue component unless treated as appropriate with radiation and/or surgery before starting on this study
• Patients must not have received prior systemic radiotherapy with strontium-89, samarium-153, rhenium-186, rhenium-188, or radium-223 dichloride (Xofigo) for the treatment of bony metastases. Prior systemic radiopharmaceutical therapy with lutetium Lu 177 vipivotide tetraxetan (Pluvicto) is permitted, but last treatment must be at least six weeks prior to starting study treatment due to the concern of bone marrow suppression
• Patients must not have unmanageable urinary incontinence
• Pregnant women are excluded from this study because Sn-117m-DTPA is a radionucleotide with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with Sn-117m-DTPA, breastfeeding should be discontinued if the mother is treated with Sn-117m-DTPA

Full record on ClinicalTrials.gov

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