Feasibility of Sequential Radium Ra-223 Dichloride After Triplet Therapy in High‑Volume Metastatic Hormone‑Sensitive Prostate Cancer Patients (Phase II)

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What is this study about?

The study focuses on Metastatic Hormone-Sensitive Prostate Cancer, a form of prostate cancer that has spread to other parts of the body, often the bones, but still responds to hormone‑blocking treatments. Participants receive an initial “triplet” regimen, which combines three standard cancer medicines, followed by an injection of Radium-223, a radioactive drug that seeks out cancer cells in bone and helps control disease growth.

The purpose of the study is to determine whether giving Radium-223 after the triplet regimen is feasible for patients with high‑volume disease. After completing the initial combination therapy, patients receive a series of Radium-223 injections, typically one every four weeks, with up to five doses planned. Throughout the treatment period, doctors check blood tests, scan images, and ask about pain and quality of life to track how well the therapy is tolerated and whether the cancer remains under control.

1 baseline evaluation

after joining the study, you will undergo a series of baseline examinations to document the current status of your disease.

these examinations include blood tests to measure prostate‑specific antigen (psa) and alkaline phosphatase, imaging studies to assess bone and soft‑tissue metastases, and a review of your medical history.

the results provide a reference point for later comparisons.

2 induction triplet therapy

following the baseline evaluation, you will receive a combination of three anticancer drugs, referred to as triplet therapy.

the drugs are administered according to the study schedule, which may involve oral or intravenous dosing.

the purpose of this phase is to reduce tumor burden before the radium‑223 treatment.

you will be monitored regularly for side effects and treatment response during this period.

3 start of radium‑223 treatment

once the induction triplet therapy is completed, you will begin the radium‑223 phase of the trial.

each cycle consists of an intravenous injection of radium‑223 dichloride (brand name xofigo) at a dose of 55 kbq per kilogram of body weight.

the medication is supplied as a solution for injection and is given through a vein by a qualified health professional.

cycles are administered at intervals defined by the study protocol, with a planned total of up to five cycles.

4 monitoring during radium‑223 cycles

before each radium‑223 injection, you will have blood tests to check blood counts, psa, and alkaline phosphatase levels.

you will also be asked to report any symptoms, such as pain or side effects, using simple questionnaires.

periodic imaging may be performed to evaluate disease stability.

these assessments help determine treatment compliance and safety.

5 completion assessment

after the final radium‑223 cycle, a comprehensive assessment is performed.

blood tests are repeated to measure psa and alkaline phosphatase responses.

imaging studies are reviewed to assess radiographic progression.

quality‑of‑life questionnaires, such as the eq‑5d‑5l and fact‑p, may be completed to evaluate overall well‑being.

6 post‑treatment follow‑up

following the completion assessment, you will enter a follow‑up phase with scheduled visits.

these visits monitor long‑term outcomes, including time to next systemic therapy, overall survival, and any delayed side effects.

the follow‑up schedule is outlined in the study protocol and may involve periodic blood tests and imaging.

Who Can Join the Study?

You must be at least 18 years old.
You must have a confirmed diagnosis of prostate adenocarcinoma (prostate cancer identified by a laboratory test of the tissue).
You must have completed a first‑line “triplet” treatment that includes androgen deprivation therapy (ADT) (hormone therapy), the chemotherapy drug docetaxel, and the medication darolutamide.
You must have received four or more cycles of docetaxel and finished this chemotherapy no more than 12 weeks before the planned first dose of Ra223.
Your disease must not have progressed after finishing the triplet therapy.
You must have recovered from any side effects of the previous treatments to at most mild levels (CTCAE grade 1 or baseline).
You must have at least four bone metastases (cancer spots in the bones) seen on a bone scan, with or without spread to lymph nodes or other organs.
Your pain must be none or mild (worst pain score less than 4 on a short pain questionnaire).
You must be willing to take bone‑strengthening medicines (bisphosphonates or denosumab) plus calcium and vitamin D before the first Ra223 dose.
You must have a T‑score of –2.5 or higher on a recent DXA scan (a test that measures bone density) done within the past year.
You must have adequate organ and bone‑marrow function, meaning:
- White blood cell count (absolute neutrophil count) of at least 1.5 × 10⁹/L.
- Platelet count of at least 100 × 10⁹/L.
- Hemoglobin level of at least 9.0 g/dL.
- Total bilirubin level ≤ 1.5 times the normal limit (≤ 5.0 times if you have Gilbert’s disease).
- Liver enzymes (AST and ALT) ≤ 2.5 times the normal limit.
- Creatinine ≤ 1.5 times the normal limit.
- Creatinine clearance (CrCl) ≥ 30 mL/min.
- Albumin (a blood protein) > 25 g/L.
You must not have received any growth‑factor medication in the past 4 weeks or a blood transfusion in the past 7 days.
You must have an ECOG performance status of 0, 1, or 2 (a simple scale of how well you can carry out daily activities) and a Charlson comorbidity score of 3 or less (a score that counts other health problems).
You must be fully informed about the study and sign the informed consent form (ICF) before any study procedures.
If you have a partner who could become pregnant, you must use a condom plus another reliable birth‑control method during treatment and for at least 1 week after the last dose of darolutamide and 6 months after the last dose of Ra223.

Who Cannot Join the Study?

Having a tumor in the brain or spinal cord that has been confirmed by imaging tests.
Planning to receive any other cancer‑fighting treatments while taking part in this study.
Using a test drug (an investigational medication) within the last 4 weeks or planning to use one during the study.
Having a serious health problem such as:
- An infection that is not under control (moderate or worse). Uncontrolled infection means the infection is still active and not improving.
- A stomach or intestinal condition that stops nutrients from being absorbed, like removal of part of the stomach (gastrectomy) or a painful ulcer (peptic ulcer disease).
- Inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis.
- Bone loss in the jaw (osteonecrosis of the jaw).
- Non‑cancerous bone problems that cause extra bone growth.
- Abnormal development of the bone marrow (bone marrow dysplasia).
- Inability to control bowel movements (fecal incontinence).
- A life‑threatening illness that is not related to prostate cancer.
Having serious heart or blood‑vessel disease, including:
- Chest pain (angina) that has not been controlled in the past 3 months.
- Severe heart failure (New York Heart Association class III or IV) unless a recent heart scan shows the heart pumps at least 45% of blood (left ventricular ejection fraction ≥ 45%).
- Dangerous heart rhythm problems such as rapid or chaotic beats (ventricular tachycardia, ventricular fibrillation, torsades de pointes).
- Advanced heart block (Mobitz II second‑degree or third‑degree) without a permanent pacemaker.
- Very high blood pressure (systolic > 160 mm Hg or diastolic > 100 mm Hg) at screening.
Being allergic (hypersensitive) to any of the study medicines, their drug class, or any ingredient in them.
Having a medical reason that prevents the use of contrast dye for CT or MRI scans.
Having a medical reason that prevents the use of bone‑strengthening drugs called bisphosphonates or denosumab.
Participating in another clinical trial that uses an experimental drug.
Having problems with drug or alcohol abuse.
Having any other medical condition that the doctor believes would make it unsafe or affect the study results.
Having had another cancer in the past, except for certain skin cancers (basal cell or squamous cell), very early‑stage skin cancer (in‑situ carcinoma), or low‑grade superficial bladder cancer, or if the other cancer has been gone for at least 3 years.
Showing cancer that is getting worse while on hormone therapy (ADT) or meeting the definition of castration‑resistant prostate cancer (CRPC).
Receiving external radiation, brachytherapy (internal radiation), or local treatments such as radiofrequency ablation, cryotherapy, or high‑intensity focused ultrasound within 4 weeks before the first study dose.
Having taken chemotherapy for prostate cancer before, unless it was part of the required first‑line triple therapy for metastatic hormone‑sensitive prostate cancer.
Having major surgery within 4 weeks before starting the study treatment.
Having had whole‑body (hemibody) external radiation therapy in the past.
Using steroids (like prednisone) at a dose higher than 10 mg per day, no matter why they are being taken.
Being treated with abiraterone as part of the first‑line triple therapy for metastatic hormone‑sensitive prostate cancer.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Hospital Clinico San Carlos	Madrid	Spain
Hospital Universitario Hm Sanchinarro	Madrid	Spain

Other Sites

Site Name	City	Country
Hospital Clinic De Barcelona	Barcelona	Spain
Universidade De Santiago De Compostela	Santiago De Compostela	Spain
Hospital Universitario 12 De Octubre	Madrid	Spain
Fundacion Instituto Valenciano De Oncologia	Valencia	Spain
Complejo Hospitalario Universitario Insular Materno Infantil	Las Palmas De Gran Canaria	Spain
Hospital Clinico Universitario De Valladolid	Valladolid	Spain
Hunhbvft Dp Lz Spoep Cuae I Sung Pzg	Barcelona	Spain
Hogbfeod Upikafkrwbivy Mzggewc Du Vamalzyshp	Santander	Spain
Fqtdkfqgo Pimn Lc Iturzapyqugen Bvwfmuhvh Dnz Hosbbhya Uuatyctmhbdld Lu Pmu	Madrid	Spain

Trial status

Country	Status	Recruitment Start
Spain	Not yet recruiting	01.10.2026

Trial locations

Investigated Drugs:

Radium Ra 223 Dichloride

The trial begins with an “induction triplet therapy,” which means patients receive three standard prostate‑cancer medicines together at the start of treatment. This combination is used to quickly lower the amount of cancer in the body and prepare patients for the next step of the study.

Xofigo is a radioactive medicine that is injected into a vein after the triplet therapy is finished. It travels to the bones where prostate‑cancer cells often spread and delivers targeted radiation to kill those cancer cells while sparing most healthy tissue. This helps control the disease and may reduce bone‑related symptoms.

Investigated Diseases:

Hormone-dependent prostate cancer

Metastatic hormone-sensitive prostate cancer (mHSPC) – Metastatic hormone-sensitive prostate cancer (mHSPC) is prostate cancer that has spread beyond the prostate gland while still responding to hormonal therapy. The disease typically begins with cancer cells growing in the prostate and later spreads to bones or other organs. As it progresses, tumor cells continue to grow and may increase the level of prostate-specific antigen in the blood. The spread to distant sites can cause new lesions to appear over time. Hormone sensitivity means the cancer still relies on male hormones for growth, so changes in hormone levels influence its activity.

Trial ID:

2026-525550-11-00

Trial Phase:

Therapeutic exploratory (Phase II)

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Feasibility of Sequential Radium Ra-223 Dichloride After Triplet Therapy in High‑Volume Metastatic Hormone‑Sensitive Prostate Cancer Patients (Phase II)

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?