AzTrials
AzTrials

Metastatic Castration Resistant Prostate CancerPhase 2TATCISTNCT05219500

Targeted Alpha Therapy With 225Actinium-Prostate Specific Membrane Antigen (PSMA)-I&T of Castration-resISTant Prostate Cancer (TATCIST).

A Phase 2 study testing FPI-2265 in people with Metastatic Castration Resistant Prostate Cancer, run by Fusion Pharmaceuticals Inc. at 2 sites in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
Search all trials

Trial summary

The treatment regimen will consist of 4 doses of FPI-2265 Read more about this study

Who is it for?
Ages 18 years and older, men only
What is being tested?
FPI-2265
Could I receive a placebo?
No, everyone receives an active treatment
How many people
115 participants
Where
2 sitesUnited States
Study dates
16 Dec 2021to 31 Jul 2026
Phase
Phase 2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • Men only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Participants aged ≥ 18 years.
  • Participants must have the ability to understand and sign an approved informed consent (ICF).
  • Participants must have the ability to understand and comply with all protocol requirements.
  • Adenocarcinoma of prostate proven by histopathology.
  • Life expectancy of 6 months or more.
  • Unresectable metastases.
Show all 25Show fewer
  • Documented progressive disease (PD); progressive mCRPC will be based on at least 1 of the following criteria:
  • Serum PSA progression is defined as 2 consecutive increases in PSA over a previous reference value measured at least 1 week prior. The minimal starting value is 1.0 ng/mL, if PSA is the only indication of progression.
  • Soft-tissue progression defined as an increase ≥ 20% in the sum of the diameter (SOD) (short axis for nodal lesions and long axis for non-nodal lesions) of all target lesions based on the smallest SOD since treatment started or the appearance of one or more new lesions.
  • Progression of bone disease: evaluable disease or new bone lesions(s) by bone scan (2+2 PCWG3 criteria).
  • If known Breast Cancer gene (BRCA) mutations are present, participants should have received FDA approved therapies such as poly-ADP ribose polymerase (PARP) inhibitors and progressed.
  • Castration resistant disease with confirmed testosterone level ≤ 50 ng/dL under prior androgen deprivation therapy (ADT). Must have a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L).
  • Positive PSMA PET/CT scans, obtained with approved PSMA-ligands, defined as at least one PSMA-positive metastatic lesion and no PSMA-negative lesions.
  • ECOG-PS 0 to 1.
  • Hemoglobin (Hgb) concentration ≥ 9.0 g/dL.
  • Platelet counts ≥ 100 × 10^9/L.
  • White blood cell (WBC) count ≥ 2.0 × 10^9/L, absolute neutrophil count (ANC) > 1.5 × 10^9/L.
  • Hematological criteria cannot be met with ongoing or recent blood transfusions (within 7 days prior to the scheduled first dose of study treatment) or require growth factor support (within 21 days prior to the scheduled first dose of study treatment).
  • Alanine aminotransferase or aspartate aminotransferase ≤ 3.0 × upper limit of normal (ULN).
  • Serum total bilirubin ≤ 1.5 × ULN; in participants with Gilbert's syndrome, a total bilirubin ≤ 3 times ULN and direct bilirubin within normal limits are permitted.
  • Albumin ≥ 2.5 g/dL.
  • Serum/plasma creatinine ≤ 1.5 × ULN or creatinine clearance ≥ 60 mL/min based on the Cockcroft-Gault formula.
  • Prothrombin time, international normalized ratio or prothrombin time test < 1.5 × ULN.
  • Received ≥ 1 androgen receptor axis-targeted therapies (ARAT).
  • Participants on anti-androgen therapy are allowed to continue their treatment at the discretion of their treating physician.

Who cannot join

  • Less than 6 weeks from enrollment since last myelosuppressive therapy (including Docetaxel, Cabazitaxel, 223Ra, 153Sm, 177Lu-PSMA-617/other Lu-PSMA RLT or any other radionuclide therapy). Participants who received previous treatment with Ac-225 are excluded.
  • Participants who received more than 4 prior lines of systemic therapy for CRPC.
  • Urinary tract obstruction as evidenced by Tc-99m DTPA renal scan with diuretics.
  • Participants with skeletal metastases presenting as a superscan on a 99m Tc MDP Bone Scan.
  • Superscan is defined as a bone scan which demonstrates markedly increased skeletal radioisotope uptake relative to soft tissues in association with absent or faint renal activity (absent kidney sign).
  • Persistent baseline dry eye or dry mouth > Grade 1 from prior RLT.
Show all 16Show fewer
  • Persistent prior AEs > Grade 1 from prior anti-cancer therapies.
  • Abnormal renal function (estimated glomerular filtration rate < 60 mL/min), baseline Hgb < 9g/dL, ANC < 1.5 ×10^9/L, platelets < 100 ×10^9/L, and prothrombin time, international normalized ratio or prothrombin time test ≥ 1.5 × ULN.
  • Administration of an investigational agent ≤ 60 days or 5 half-lives, whichever is shorter, prior to Cycle 1, Week 0.
  • Known presence of central nervous system (CNS) metastases or liver metastases.
  • Active malignancy other than low-grade non-muscle-invasive bladder cancer and non-melanoma skin cancer.
  • Concurrent illness that may jeopardize the participant's ability to undergo study procedures as determined by the Investigator.
  • Symptomatic cord compression, or clinical or radiologic findings indicative of impending cord compression.
  • Concurrent serious (as determined by the investigator) medical conditions, including, but not limited to, New York Heart Association Class III or IV congestive heart failure, unstable ischemia, uncontrolled symptomatic arrhythmia, history of congenital prolonged QT syndrome, uncontrolled infection, known active hepatitis B or C, or other significant co-morbid conditions that in the opinion of the Investigator would impair study participation or cooperation.
  • Major surgery ≤ 30 days prior to enrollment.
  • Planning to conceive pregnancy during the treatment and up to 6 months after the last treatment.

Trial locations and contacts

2 sites in 1 country.

United States2 sites

  • Excel Diagnostics and Nuclear Oncology Center

    Houston, Texas, 77042

  • XCancer Omaha/Urology Cancer Center

    Omaha, Nebraska, 68130

Other trials in United States

About this study

Official title: PSMA-directed Targeted Alpha Therapy With FPI-2265 (225Ac-PSMA-I&T) for the Treatment of Metastatic Castration-resISTant Prostate Cancer (TATCIST). A Phase II Clinical Trial.

The treatment regimen will consist of 4 doses of FPI-2265

Read the detailed description

The treatment regimen will consist of 4 doses of FPI-2265, administered at 8 ± 1 week intervals, with an initial activity of 100 kilobecquerel (kBq)/kg (±10%).

Additional doses will be administered at 100 kBq/kg (±10%) with the following exceptions:

  • Participants who experience dose-modifying events.
  • Participants with a confirmed decline in PSA>=50%.
Being tested
FPI-2265

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • FPI-2265Drug

    Also called Ac225-PSMA I&T

    Small molecule capable of binding to the domain of PSMA radiolabeled with Ac225

Study groups in NCT05219500
Study groupRoleWhat they receive
FPI-2265ExperimentalAll patients will receive FPI-2265, administered at 8 ± 1-week interval, with the initial activity of 100 kBq/kg (±10%).
Receives: Drug: FPI-2265

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. To evaluate the effect of FPI-2265 on prostate-specific antigen (PSA) in participants with mCRPC.

    Frequency and proportion of participants with PSA50, defined as ≥ 50% decline in PSA level by 12-weeks after the first treatment.

    Measured: From start of treatment until 12 weeks after the first treatment.

Secondary outcomes (3)

  1. To evaluate the safety and tolerability of FPI- 2265.

    • Frequency, duration and severity of treatment emergent adverse events (TEAEs) evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0 (NCI-CTCAE v5.0).
    • Changes in clinical laboratory, electrocardiograms (ECGs) and physical examinations compared to baseline.

    Measured: From first treatment dose to up to 24 months after last treatment.

  2. To evaluate the anti-tumor activity of FPI-2265.

    • Maximum % PSA decline.
    • PSA progression free survival (PFS).
    • Time to best PSA response
    • Objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1).
    • Disease control rate (DCR) per RECIST v1.1.
    • Duration of response (DoR) based on RECIST v1.1/Prostate Cancer Clinical Trials Working Group 3 (PCWG3) criteria.
    • Radiographic progression-free survival (rPFS) per PCWG3 criteria.
    • Overall survival (OS).

    Measured: From first treatment until date of radiographic progression or date of death from any cause, whichever comes first, assessed up to 24 months after last treatment.

  3. To assess the impact of FPI-2265 on participant reported outcomes.

    • The frequency and proportion of participants with an improvement in bone pain levels.
    • Change in quality of life (QoL) over time.

    Measured: From first treatment until 24 months after last treatment.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted2 Feb 2022
  2. Study start16 Dec 2021
  3. Primary completion30 May 2025
  4. Study completion31 Jul 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
115 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05219500
Sponsor's protocol ID
FPI-2265-201
Acronym
TATCIST
Status last verified
Apr 2026
First submitted
20 Dec 2021
Last updated
3 Apr 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing FPI-2265 in people with Metastatic Castration Resistant Prostate Cancer, run by Fusion Pharmaceuticals Inc. at 2 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 25 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 3 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

To evaluate the effect of FPI-2265 on prostate-specific antigen (PSA) in participants with mCRPC. (time frame: From start of treatment until 12 weeks after the first treatment.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05219500.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Apr 2026.

AzTrials uses cookies for analytics and advertising. You can accept or reject them; the site works either way. Privacy Policy.

Free account

Log in to keep searching

You’ve used your 3 free searches. AzTrials is free: log in or create a free account to keep searching clinical trials and save the ones you want to follow.

Create a free accountLog in