Phase II Study of Lutetium (177Lu) Zadavotide Guraxetan Radioligand Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer

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What is this study about?

The study focuses on patients with Prostate cancer that has spread to other parts of the body (metastatic) and no longer responds to hormone therapy (castration‑resistant). The treatment being tested is an injectable radioligand called 177Lu-PSMA I&T, which delivers a small amount of radiation directly to cancer cells that show a protein called PSMA on their surface.

The purpose of the study is to evaluate how long the disease remains controlled after receiving the drug. Participants will receive a series of intravenous infusions of the medication, with each infusion given a few weeks apart. Throughout the trial, blood tests will measure PSA (a protein that indicates prostate cancer activity), and imaging scans such as a special scan that shows PSMA activity (PSMA PET/CT) and a scan that measures radiation dose to the tumor (SPECT/CT) will be performed to track tumor changes. Standard imaging criteria (RECIST) are used to assess whether tumors shrink, stay the same, or grow.

After the treatment phase, patients are followed for several months with regular check‑ups, blood tests, and scans to monitor disease status, side effects, pain levels, and overall well‑being. The study records how long patients live without the disease getting worse, as well as any improvements in symptoms or quality of life.

1 joining the study

after you agree to take part, you are officially enrolled and become a participant in the trial.

2 baseline assessments

before any treatment, you will undergo a series of tests to record your starting condition. these include a blood test to measure psa (prostate‑specific antigen), imaging scans such as psma pet/ct (a scan that shows prostate cancer activity), and possibly an fdg‑pet/ct scan, as well as a contrast‑enhanced ct scan to look at soft‑tissue disease.

your overall health will be evaluated using the who/ecog performance status scale, your pain level will be measured on a visual analogue scale from 1 to 10, and you will complete questionnaires about your quality of life.

3 first treatment infusion

you will receive the study medication, lutetium-177 psma i&t, as a solution for injection. the dose is 8.14 gbq (gigabecquerel) and it is given by intravenous infusion (through a vein).

4 immediate post‑infusion monitoring

after the infusion, you will be observed for a short period to check for any immediate side effects. a sct/ct scan will be performed to measure the radiation dose that reached the tumour and normal tissues.

5 follow‑up visits and monitoring

you will attend regular follow‑up visits where blood is drawn to measure psa levels, and you will be asked again about pain, performance status, and quality of life.

scheduled imaging assessments will be performed at week 12 and week 24 after the first infusion, as well as at the end of treatment and at the end of the study. these scans include psma pet/ct and contrast‑enhanced ct to evaluate tumour response.

each visit will also include a review of any adverse events or toxicity you may have experienced.

6 additional treatment cycles (if required)

based on the results of your baseline and follow‑up assessments, the study team may decide to give you additional doses of lutetium-177 psma i&t. each additional dose follows the same procedure as the first infusion: a single intravenous infusion of the individually adapted dose, followed by the same monitoring and imaging schedule.

7 end of treatment evaluation

when the predetermined number of treatment cycles is completed, a final set of assessments is performed. this includes the last imaging scans, the final blood test for psa, and the last questionnaires on pain, performance status, and quality of life.

8 end of study follow‑up

after treatment ends, you will continue to be followed for a period defined by the study protocol. during this time, the study records overall survival, any further disease progression, and long‑term safety information.

Who Can Join the Study?

You have prostate cancer that was confirmed by looking at a tissue sample under a microscope (histologically confirmed adenocarcinoma).
Your cancer shows up on a special scan that detects a protein called PSMA and keeps growing even though your blood testosterone level is very low (≤ 1.7 nmol/L), meaning it is castration‑resistant.
You have already taken at least one medicine that blocks the hormone receptor (an ARPI, such as enzalutamide or abiraterone) and you have received, or cannot receive, a type of chemotherapy called a taxane.
Your disease is getting worse, shown by either new or larger tumors on scans (bone scan, CT, or special PET scans) or by a rising PSA level that meets these rules: two tests at least one week apart, a third test to confirm, a PSA of at least 5 ng/mL, and at least 25 % higher than the lowest recent level (nadir).
Your overall health and ability to perform daily activities is rated as WHO/ECOG performance status 0, 1, or 2.
You are 18 years of age or older.
Doctors expect you to live longer than 6 months.
You have cancer that has spread to bone or other organs, and this spread can be seen on a PSMA‑PET/CT scan (measurable bone or visceral metastasis).

Who Cannot Join the Study?

Have you already received radiopharmaceutical agents (radioactive drugs) for prostate cancer?
Are you currently receiving cytotoxic chemotherapy (drugs that kill cancer cells), immunotherapy (treatments that use the immune system), other isotope treatment, a PARP inhibitor, biological therapy, or any investigational therapy (experimental medicines)?
Do you have a blockage of the urinary tract, uncontrolled urine leakage (incontinence), or severe swelling of the kidney area called hydronephrosis?
Have you had another cancer (except certain skin cancers called basal, in situ, or squamous cell skin cancers, or a superficial bladder cancer) and not been cancer‑free for at least three years?
Do you have a serious medical or mental illness that your doctor believes would keep you from finishing treatment or attending follow‑up visits?
Does a bone scan show a “superscan,” meaning unusually high bone activity that could affect study results?
Do you have cancer that has spread to the brain (brain metastases), whether it causes symptoms or not?
Do you have pressure on the spinal cord that causes symptoms (cord compression)?
Do you have serious blood disease (hematologic), kidney disease (renal), or brain/spinal‑cord disease (CNS) that your doctor thinks makes participation unsafe?
Do you have severe heart disease, such as serious chest pain from blocked arteries (coronary artery disease), heart failure you were born with (congenital heart failure), or heart failure that is class 3 or 4 on the NYHA (New York Heart Association) scale?
Have you had radiotherapy (radiation treatment) or chemotherapy within two months before the planned study treatment?

Where you can join this trial?

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Other Sites

Site Name	City	Country	Status
Region Uppsala	Uppsala	Sweden

Trial status

Country	Status	Recruitment Start
Sweden	Not yet recruiting	01.11.2026

Trial locations

Investigated Drugs:

Lutetium (177Lu) Zadavotide Guraxetan

Lutetium-177 PSMA I&T is a type of radioligand therapy that delivers a small amount of radiation directly to prostate cancer cells that have spread to other parts of the body. The medication is given through an intravenous infusion, where the radioactive lutetium is attached to a molecule that specifically binds to the PSMA protein on cancer cells. Once attached, the radiation helps to damage and kill the cancer cells while limiting exposure to healthy tissue. In this study, each patient receives a dose that is individually adjusted based on their own disease characteristics, aiming to slow the progression of metastatic, castration‑resistant prostate cancer.

Investigated Diseases:

Hormone-refractory prostate cancer

Metastatic castration‑resistant prostate cancer – This form of prostate cancer starts in the gland that produces semen and continues to grow even when testosterone levels are very low. It spreads beyond the prostate to other parts of the body, most often to the bones and nearby lymph nodes. As the disease advances, the cancer cells multiply and form new tumors in these distant sites, leading to an increase in cancer burden over time. The progression is monitored by changes in the amount of prostate‑specific antigen (PSA) in the blood and by imaging that shows new or growing lesions.

Trial ID:

2026-527110-23-00

Protocol code:

LuPRO

Trial Phase:

Therapeutic exploratory (Phase II)

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Phase II Study of Lutetium (177Lu) Zadavotide Guraxetan Radioligand Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?