Phase I Study of Docetaxel and 177-Lutetium-PSMA-I&T in First-Line Treatment for Patients With Metastatic Castration-Resistant Prostate Adenocarcinoma (Lutécio)

May 14, 2026 updated by: Instituto do Cancer do Estado de São Paulo
This is a Phase I, open-label, single-center study evaluating the safety, tolerability, and recommended Phase II dose of docetaxel when combined with a fixed dose of 177-Lutetium-PSMA-I&T in chemotherapy-naïve patients with metastatic castration-resistant prostate cancer (mCRPC). Patients will receive standard androgen deprivation therapy, docetaxel at escalating doses (50 mg/m², 60 mg/m², 75 mg/m² every 3 weeks), and 177Lu-PSMA-I&T at a fixed dose of 7.4 GBq every 6 weeks (up to 4 cycles). A 3+3 dose escalation design will be employed. Secondary endpoints include safety profile, treatment-limiting toxicities, treatment completion rate, and delayed toxicity. Exploratory endpoints include PSA response, radiographic progression-free survival (rPFS), and PERCIST-based response rate.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a Phase I, open-label, single-center study designed to evaluate the safety, tolerability, and to determine the recommended Phase II dose (RP2D) of docetaxel when combined with a fixed dose of 177Lu-PSMA-I&T in patients with metastatic castration-resistant prostate cancer (mCRPC) who have not previously received chemotherapy for castration-resistant disease.

All participants will continue receiving androgen deprivation therapy (ADT) throughout the study. The treatment regimen includes docetaxel administered intravenously every 3 weeks at escalating doses of 50 mg/m², 60 mg/m², and 75 mg/m² (up to 10 cycles), combined with 177Lu-PSMA-I&T at a fixed dose of 7.4 GBq every 6 weeks, for up to 4 cycles. A traditional 3+3 dose-escalation design will be used, allowing sequential patient enrollment and assessment of dose-limiting toxicities (DLTs) during the first 3 weeks to establish the optimal docetaxel dose for future studies.

Treatment will continue until completion of 10 cycles of docetaxel and 4 cycles of 177Lu-PSMA-I&T, or until disease progression, unacceptable toxicity, or withdrawal of consent. Imaging exams, including SPECT, will be performed after each lutetium administration for dosimetry assessment.

The primary endpoint is the determination of the RP2D of docetaxel when combined with 177Lu-PSMA-I&T. Secondary endpoints include evaluation of the overall safety profile, incidence of DLTs, treatment completion rate, and monitoring of late toxicities. Exploratory endpoints include PSA response (≥50% decline), radiographic progression-free survival (rPFS), and response rate based on PERCIST criteria using PSMA-PET.

Patients will undergo imaging assessments every 6 weeks (±7 days), including PSMA-PET/CT, FDG-PET/CT, CT scans, and bone scintigraphy. Laboratory tests will be performed every 3 weeks during treatment and every 6 weeks during the post-treatment follow-up, for up to 24 weeks.

Key inclusion criteria include: male patients aged 18 years or older, histologically confirmed adenocarcinoma of the prostate, documented metastatic disease by conventional imaging, castration-resistant disease with testosterone levels <50 ng/mL, ECOG performance status of 0-1, adequate organ function, and positive 68Ga-PSMA-PET/CT uptake according to protocol-defined parameters.

Key exclusion criteria include: presence of small-cell or neuroendocrine tumor components, prior chemotherapy or radiopharmaceuticals for castration-resistant disease, recent or active second malignancies, significant discordance between FDG-PET/CT and PSMA-PET/CT, visible brain metastases, severe urinary incontinence, or any clinical condition that, in the investigator's judgment, would contraindicate the use of docetaxel or 177Lu-PSMA-I&T. Full details of inclusion and exclusion criteria are provided in the study protocol.

This study aims to establish the optimal dose of docetaxel in combination with 177Lu-PSMA-I&T and to generate preliminary safety and efficacy data for treating patients with metastatic castration-resistant prostate cancer.

Study Type

Interventional

Enrollment (Estimated)

18

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Brazil
      • São Paulo, Brazil, 01246000
        • Instituto do Cancer do Estado de Sao Paulo - ICESP
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Men aged 18 years or older.
  2. Histological or cytological diagnosis of prostate adenocarcinoma. The presence of intraductal or cribriform carcinoma will be allowed.
  3. Presence of metastatic disease on conventional imaging exams (bone scintigraphy and/or CT scan or MRI).
  4. Patients with castration-resistant disease, defined as testosterone <50 ng/mL in the context of prior orchiectomy or ongoing androgen deprivation therapy (ADT) with LHRH agonists or antagonists, plus at least one of the criteria below:
  5. PSA ≥2.0 ng/mL with at least two consecutive PSA rises at intervals of at least 1 week.
  6. Radiologic progression defined by the investigator.
  7. Clinical progression defined by the investigator.
  8. Performance status per the Eastern Cooperative Oncology Group (ECOG) equal to 0 or 1.
  9. Willingness to continue ongoing ADT.

  10. Adequate organ function as defined below:

    • Parameter Requirement
    • Neutrophils ≥ 1,500/µL
    • Hemoglobin ≥ 12 g/dL
    • Platelets ≥ 100,000/µL
    • Creatinine ≤ 1.5 x upper limit of normal
    • Potassium > 3.5 mmol/L and <5.0 mmol/L
    • Total Bilirubin ≤ ULN (unless Gilbert's disease)
    • AST (TGO) ≤ 2.5 x ULN
    • ALT (TGP) ≤ 2.5 x ULN
  11. 68Ga-PSMA-PET/CT performed during the screening phase showing metastatic (extraprosthetic and extrapelvic) disease with radiotracer uptake and:
  12. SUVmax ≥20 in at least one site;
  13. SUVmax >10 in all other measurable metastatic sites.
  14. Lesions with uptake at least 1.5 times greater than hepatic background will be considered measurable.

Exclusion Criteria:

  1. Presence of any small-cell or neuroendocrine component of prostate carcinoma.
  2. Prior receipt of chemotherapy or radiopharmaceuticals in the castration-resistant setting.
  3. Presence of another active malignancy requiring treatment or a cancer diagnosis within the past 5 years. Carcinoma in situ of any site, squamous cell carcinoma of the skin, basal cell carcinoma of the skin, or papillary bladder tumors will be allowed if previously treated.
  4. Severe urinary incontinence at the investigator's discretion.
  5. 18F-FDG-PET/CT will be performed during screening and will be considered exclusionary if there is discordance with the 68Ga-PSMA-PET/CT. Discordance is defined as FDG-hypermetabolic lesions with absent or low PSMA uptake (SUVmax <10) in more than 50% of measurable metastatic lesions.
  6. Patients with brain metastases visible on 68Ga-PSMA-PET/CT.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Docetaxel 50 mg/m² + 177Lu-PSMA-I&T
Patients will receive docetaxel 50 mg/m² IV every 3 weeks plus 177Lu-PSMA-I&T 7.4 GBq IV every 6 weeks. all patients will continue androgen deprivation therapy.
Drug: Docetaxel 50mg/m2
Intravenous, 50 mg/m², every 3 weeks, up to 10 cycles
Radiation: 177Lu-PSMA-I&T
Intravenous administration at a fixed dose of 7.4 GBq every 6 weeks, up to 4 cycles.
Experimental: Docetaxel 60 mg/m² + 177Lu-PSMA-I&T
Patients will receive docetaxel 60 mg/m² IV every 3 weeks plus 177Lu-PSMA-I&T 7.4 GBq IV every 6 weeks. all patients will continue androgen deprivation therapy.
Radiation: 177Lu-PSMA-I&T
Intravenous administration at a fixed dose of 7.4 GBq every 6 weeks, up to 4 cycles.
Drug: Docetaxel 60mg/m2
Intravenous, 60 mg/m², every 3 weeks, up to 10 cycles
Experimental: Docetaxel 75 mg/m² + 177Lu-PSMA-I&T
Patients will receive docetaxel 75 mg/m² IV every 3 weeks plus 177Lu-PSMA-I&T 7.4 GBq IV every 6 weeks. all patients will continue androgen deprivation therapy.
Radiation: 177Lu-PSMA-I&T
Intravenous administration at a fixed dose of 7.4 GBq every 6 weeks, up to 4 cycles.
Drug: Docetaxel 75 mg/m²
Intravenous, 75 mg/m², every 3 weeks, up to 10 cycles

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Recommended Phase II Dose (RP2D) of docetaxel in combination with 177Lu-PSMA-I&T
Time Frame: First 3 weeks
Determination of the recommended Phase II dose using a standard 3+3 dose-escalation design.
First 3 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of dose-limiting toxicities (DLTs)
Time Frame: first 3 weeks.
Incidence of dose-limiting toxicities (DLTs)
first 3 weeks.
Overall safety profile (CTCAE v5.0)
Time Frame: Up to 24 weeks
Overall safety profile (CTCAE v5.0)
Up to 24 weeks
Treatment completion rate
Time Frame: Up to 24 weeks
Treatment completion rate (≥4 doses of lutetium and ≥7 doses of docetaxel)
Up to 24 weeks
Incidence of late toxicities
Time Frame: Up to 24 weeks post-treatment
Incidence of late toxicities
Up to 24 weeks post-treatment

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
PSA50 response rate
Time Frame: Up to 24 weeks
PSA50 response rate (≥50% decline from baseline)
Up to 24 weeks
Radiographic progression-free survival (rPFS) per PCWG3
Time Frame: Up to 12 months
Radiographic progression-free survival (rPFS) per PCWG3
Up to 12 months
PERCIST-based response rate via PSMA-PET
Time Frame: Up to 12 months
PERCIST-based response rate via PSMA-PET
Up to 12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Instituto do Cancer do Estado de São Paulo

Investigators

  • Study Director: Carlos A Buchpiguel, MD, PhD, Full Professor, Department of Radiology and Oncology
  • Principal Investigator: José Mauricio Mota, MD, PhD, Medical oncology

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

September 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

September 26, 2025

First Submitted That Met QC Criteria

December 18, 2025

First Posted (Actual)

January 5, 2026

Study Record Updates

Last Update Posted (Actual)

May 18, 2026

Last Update Submitted That Met QC Criteria

May 14, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NP2028

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

It has been decided not to share individual participant data (IPD) related to the study for several reasons. Protecting the privacy of participants is a priority.

Sharing IPD may expose sensitive information that, even when de-identified, can be traced back to individuals. Furthermore, the complexity of the data makes sharing challenging without the risk of misunderstandings or misinterpretations, which could compromise the integrity of the research. Sharing IPD without the explicit consent of participants may violate ethical principles of respect and protection. There is also a need to comply with regulatory guidelines governing data sharing to avoid potential legal issues. Finally, the focus will be on disseminating aggregated results that can benefit the scientific community and the public without compromising individual privacy.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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