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Study to Identify Unknown Primary Cancer Using [18F]-AlF-FAPI-74 PET-CT for Patients with Carcinoma of Unknown Primary

Fast replyInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on a condition known as Carcinoma of Unknown Primary (CUP). This is a type of cancer where the primary origin of the tumor is not identified despite thorough testing. The study will use a special imaging technique called [18F]F-FAPI PET-CT to help locate the primary tumor in patients diagnosed with CUP. The treatment involves an injection of a solution called [18F]-AlF-FAPI-74, which is a chemical substance designed to help highlight cancer cells during the imaging process.

The purpose of the study is to determine how effective the [18F]F-FAPI PET-CT scan is in identifying the primary tumor in patients with CUP. Participants will receive an injection of the [18F]-AlF-FAPI-74 solution, followed by a PET-CT scan. This scan combines two imaging techniques, PET (Positron Emission Tomography) and CT (Computed Tomography), to provide detailed pictures of the inside of the body. The study aims to see if this method can accurately detect the primary tumor that other standard tests have not been able to find.

Throughout the study, some participants may receive a placebo instead of the active solution to compare the results. The trial will assess the ability of the [18F]F-FAPI PET-CT to correctly identify the primary tumor and evaluate its sensitivity and specificity, which are measures of how well the test can detect the disease and distinguish it from other conditions. The study is expected to continue until 2026, with recruitment starting in 2024.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Participation begins after meeting the eligibility criteria, which include being 18 years or older and having a confirmed metastatic disease without a known primary tumor, despite standard diagnostic procedures.

  2. Step 2

    Initial assessment

    An initial assessment is conducted to confirm eligibility and gather baseline health information. This may involve reviewing medical history and previous diagnostic results.

  3. Step 3

    Administration of the solution

    The medication used in this study is called [18F]-AlF-FAPI-74. It is a solution for injection administered intravenously. The exact dosage and frequency are determined by the study protocol and medical team.

  4. Step 4

    PET-CT scan

    After the injection, a PET-CT scan is performed. This imaging test helps to identify the primary tumor in patients with carcinoma of unknown primary origin. The scan uses the injected solution to highlight areas of interest.

  5. Step 5

    Follow-up and monitoring

    Following the scan, there may be additional follow-up appointments to monitor health and assess the outcomes of the scan. The frequency and duration of these follow-ups depend on individual health needs and study requirements.

  6. Step 6

    Completion of participation

    Participation in the study concludes after the final follow-up. The study is estimated to end by August 31, 2026, but individual participation may vary based on when one joins the study.

Who can join the trial?

5 criteria

  • Must be **18 years old** or older.
  • Must have a **confirmed spread of cancer** to other parts of the body, known as metastatic disease, without finding the original tumor after standard tests.
  • The standard tests must include a special type of scan called **[18F]FDG PET-CT**.
  • Both **men and women** can participate.
  • Participants should not be from a **vulnerable population**, meaning they should not be in a group that needs special protection or care.

Who cannot join the trial?

3 criteria

  • Patients who are not diagnosed with Carcinoma of Unknown Primary cannot participate. This is a type of cancer where the original location of the cancer is not known.
  • Patients who are not within the specified age range cannot participate. The age range includes adults and older adults.
  • Patients who are part of a vulnerable population cannot participate. Vulnerable populations include groups that may need special protection or care.
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Investigated drugs

[18F]F-FAPI is a special imaging agent used in PET-CT scans. It helps doctors find the original location of a cancer when it is not known. This agent works by highlighting areas in the body where cancer cells might be present, making it easier for doctors to see them on the scan.

What is already known about the treatment

[18F]F-FAPI – This medication is administered through a PET-CT scan, where it is used as a radiotracer to help identify the primary tumor in patients with carcinoma of unknown primary origin. Currently, it is being studied in clinical trials to assess its effectiveness in locating the primary cancer site. The main therapeutic indication is for use in diagnostic imaging to improve cancer detection. At the molecular level, [18F]F-FAPI binds to fibroblast activation protein, which is often overexpressed in cancerous tissues, allowing for enhanced imaging of tumors. It is classified as a diagnostic radiopharmaceutical.

Investigated diseases

Carcinoma of Unknown Primary – This is a type of cancer where the primary origin of the tumor is not identified. It is characterized by the presence of metastatic cancer cells in the body, but the location where the cancer began is unknown. The disease often presents with symptoms related to the areas where the cancer has spread, rather than where it started. It can affect various organs and tissues, making it challenging to determine the original site. The progression of the disease depends on the spread and growth of the metastatic tumors. Identifying the primary site can be difficult, and the disease is often diagnosed through exclusion of other known cancers.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-505592-69-00Estimated enrolment50 patientsSponsorErasmus Universitair Medisch Centrum Rotterdam (Erasmus MC)

sourced from the EU Clinical Trials Register and site verification

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