Phase I study of 161Tb-PSMA-1 therapy and gallium‑68 gozetotide imaging in adult patients with metastatic clear cell renal cell carcinoma

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What is this study about?

The study focuses on adults with metastatic clear cell renal cell carcinoma, a type of kidney cancer that has spread to other parts of the body. The treatment being tested is a radioactive drug called 161Tb-PSMA-1, which is given by a needle into a vein.

The purpose of the study is to determine the highest dose that can be given safely and the dose that should be used in later studies. This early‑stage, Phase I trial will give participants the drug in several treatment cycles lasting a few weeks each, with regular check‑ups to watch for side effects and to see how the cancer responds.

The drug is delivered intravenous, meaning it goes directly into the bloodstream through a small tube placed in a vein. Participants will stay at the clinic for a short period after each infusion while staff monitor vital signs and any possible reactions. Follow‑up visits will include simple scans and blood tests to track tumor size and overall health, and any problems will be recorded and treated according to standard medical guidelines.

1 baseline assessments

after joining the study, undergo a series of evaluations that include a review of medical history, physical examination, blood and urine tests, and standard imaging scans to document the extent of metastatic clear cell renal cell carcinoma.

2 diagnostic imaging with <b>gallium-68 gozetotide</b>

receive an intravenous injection of gallium-68 gozetotide at a dose of 2.2 mbq per kilogram of body weight (megabecquerel per kilogram).

the tracer circulates in the bloodstream and binds to prostate‑specific membrane antigen (psma) on tumor cells, allowing a positron emission tomography (pet) scan to visualize the location and intensity of disease.

the pet scan results are used to confirm that the cancer expresses psma and is suitable for the subsequent therapeutic infusion.

3 first therapeutic infusion of <b>161tb‑psma‑1</b>

receive a single intravenous infusion of 161tb‑psma‑1 at a fixed dose of 11.5 gbq (gigabecquerel).

the infusion is administered in a clinical setting under observation; the radioactive compound targets psma‑positive cancer cells and delivers therapeutic radiation.

4 monitoring for dose‑limiting toxicities (first 6 weeks)

attend scheduled clinic visits weekly for the first six weeks after the therapeutic infusion.

at each visit, blood tests, urine tests, and symptom assessments are performed to identify any adverse events that could be considered dose‑limiting toxicities, meaning side effects severe enough to limit the amount of drug that can be safely given.

5 response evaluation at 24 weeks

return for a follow‑up visit approximately 24 weeks after the first infusion.

undergo imaging studies (such as ct or pet scans) to assess tumor response, classified as complete response, partial response, stable disease, or progression according to standard criteria.

the evaluation determines the objective response rate and disease control rate at the 24‑week time point.

6 continued follow‑up

participate in periodic visits after the 24‑week assessment to monitor overall disease status, progression‑free survival, and overall survival.

each visit includes clinical examination, laboratory tests, and imaging as needed until the study concludes or until the patient withdraws.

Who Can Join the Study?

Must be a male or female who is at least 18 years old when signing the consent form.
Must be able to understand, sign, and date a written informed consent form before any study procedures.
Must have medical insurance coverage.
Must be willing and able to attend all study visits and follow the required procedures.
Must have a confirmed diagnosis of metastatic clear cell renal cell carcinoma that has gotten worse after at least two previous treatments, including at least one anti‑VEGFR therapy (a drug that blocks blood‑vessel growth to the tumor) and at least one immunotherapy (a medicine that helps the immune system fight cancer).
Must have recent imaging that shows the cancer is growing and that the disease can be measured using RECIST v1.1 (a standard way doctors measure tumor size).
Must have a positive PSMA‑PET scan (a special imaging test) that meets specific criteria:
- If cancer is only outside the liver, at least 50% of those lesions must be positive.
- If cancer is both outside the liver and in the liver, at least 50% of the outside‑liver lesions and at least 80% of liver lesions larger than 1 cm (called supracentimetric) must be positive.
- If cancer is only in the liver, at least 80% of liver lesions larger than 1 cm must be positive.
(Terms: extra‑hepatic means outside the liver; supracentimetric means larger than one centimeter.)
Must have a life expectancy of at least 6 months.
Must have an ECOG performance status of 0‑1 (indicating full activity or slight symptoms) and a Karnofsky Performance Status of 80% or higher (indicating the ability to carry out most daily activities).
Must have adequate organ function as shown by laboratory tests (blood work indicating the kidneys, liver, blood cells, etc., are working well).
Women who could become pregnant must have a negative pregnancy test and agree to use one highly effective form of contraception from the start of treatment until 6 months after the last dose.
Men who are capable of fathering children must also use a highly effective form of contraception during treatment and for 6 months after the final dose.

Who Cannot Join the Study?

Active brain or spinal spread of cancer (including metastases to the central nervous system, epidural space, or leptomeningitis) means you cannot join the study. If you had brain metastases that were treated, you may be allowed only if they have been stable (no growth on scans for at least four weeks), you have no new brain lesions, and you have not taken high‑dose steroids (more than 10 mg per day of methylprednisolone or an equivalent) for at least four weeks.
Previous treatment with any radiopharmaceutical (a drug that contains a radioactive element used for imaging or therapy) excludes you from participation.
Ongoing side effects from earlier cancer treatments that have not improved to a mild level (grade 1 or lower) prevent entry, except for mild anemia if another specific condition is met. Persistent immune‑related side effects that are more than mild also exclude you, unless they are well‑controlled with replacement therapy (for example, hormone replacement for endocrine problems).
Other cancers within the past two years (except for certain skin cancers like basal or squamous cell carcinoma, cervical carcinoma in place, or localized prostate cancer) make you ineligible.
History of serious lung scarring or inflammation such as idiopathic pulmonary fibrosis, non‑infectious pneumonitis, interstitial lung disease that needed steroids, current lung inflammation, drug‑induced lung disease, or any active lung inflammation excludes you.
Use of prohibited medicines or procedures that are listed in the study’s exclusion table prevents participation.
Significant bleeding problems such as noticeable blood in urine, vomit, or cough (more than about half a teaspoon), a history of clotting disorders, or major bleeding events (like lung bleeding) within the last three months disqualify you. If you are on blood‑thinning medication, you can only join if the dose and way you take it have been unchanged for at least two weeks.
Active uncontrolled infection (an infection that is not being effectively treated) makes you ineligible.
Pregnancy or breastfeeding prevents participation in the trial.

Where you can join this trial?

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Other Sites

Site Name	City	Country	Status
Cbkegq Lymf Bkxddl	Lyon	France

Trial status

Country	Status	Recruitment Start
France	Not yet recruiting	30.09.2026

Trial locations

Investigated Drugs:

Gozetotide

Gallium-68 gozetotide is a radioactive substance that is injected into a vein to help doctors see how certain tumors grow and spread. It works with a special type of scan called a PET scan, which creates detailed pictures of the inside of the body. In this study, it is used before the treatment to locate and measure the kidney cancer that has spread to other parts of the body, so the medical team can plan the best approach for therapy.

161Tb-PSMA-1 is a new therapeutic agent that also goes into the bloodstream. It is designed to find and attach to a protein called PSMA, which is often found on the surface of kidney cancer cells that have spread. Once attached, the radioactive part of the drug delivers targeted radiation directly to the cancer cells, helping to destroy them while limiting damage to healthy tissue. In this trial, patients receive this treatment to determine the safest and most effective amount for future use.

Metastatic clear cell renal cell carcinoma – Metastatic clear cell renal cell carcinoma is a type of kidney cancer that originates from the clear cells of the renal tubules. It begins as a primary tumor in the kidney and can spread through the bloodstream or lymphatic system to distant sites such as the lungs, bones, or liver. As the disease advances, the metastatic lesions increase in size and may cause organ‑specific symptoms, while the original kidney tumor may continue to grow.

Trial ID:

2026-525526-38-00

Protocol code:

ET26-035

Trial Phase:

Human Pharmacology (Phase I) – Other

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Phase I study of 161Tb-PSMA-1 therapy and gallium‑68 gozetotide imaging in adult patients with metastatic clear cell renal cell carcinoma

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?