The Value of 68Ga-FAPI PET/CT for Evaluating Peritoneal Treatment Response (INTERACT-FAPI)

Peritoneal metastases (PM), commonly originating from gastrointestinal and ovarian cancers, are associated with a poor prognosis and limited treatment options due to the diffuse nature of the disease and the inability of systemic chemotherapy to adequately penetrate the peritoneal surface. Intraperitoneal (IP) chemotherapy has emerged as a potential treatment modality for patients with extensive PM, allowing for higher local drug concentrations while minimizing systemic toxicity. However, current response evaluation methods, such as CT scans, have low sensitivity for detecting PM, and second-look laparoscopy, although more accurate, is invasive and unsuitable for repeated assessments. The ⁶⁸Ga-FAPI PET/CT scan offers a promising non-invasive alternative for assessing peritoneal response to IP chemotherapy. This imaging technique targets the fibroblast activation protein, which is overexpressed in cancer-associated fibroblasts within the tumor microenvironment. Early studies have shown that ⁶⁸Ga-FAPI PET/CT is a highly sensitive too in detecting peritoneal metastases. Given these advantages, the investigators hypothesize that ⁶⁸Ga-FAPI PET/CT could improve the evaluation of treatment response in patients undergoing IP chemotherapy for PM, offering a non-invasive and accurate alternative to current methods. The primary objective of this study is to investigate the accuracy of ⁶⁸Ga-FAPI PET/CT for evaluating peritoneal response in patients with peritoneal metastases undergoing repeated IP chemotherapy.

Study Overview

• Status: Not yet recruiting
• Conditions: Peritoneal Metastasis; FAPI
• Intervention / Treatment: Drug: ⁶⁸Ga-FAPI-46

• Study Type: Interventional
• Enrollment (Estimated): 16
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Micha de Neijs; Phone Number: +31 10 70 39640; Email: m.deneijs@erasmusmc.nl

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• A planned start of repeated IP chemotherapy (with or without the combination of systemic chemotherapy) for macroscopic peritoneal metastases;
• WHO-performance score of 0 to 1;
• Aged 18 years or older;
• Written informed consent according to the ICH-GCP and national/local regulations.

Exclusion Criteria:

• Impaired renal function, defined as eGFR <25 ml/min/1,73 m2. An exception can be made in consultation with the treating physician;
• Pregnancy/breastfeeding. For the latter, temporary discontinuation may be considered;
• Known allergic reaction to therapeutic radiopharmaceuticals;
• Inability to lie still on the back for the duration of PET-CT;
• Any (other) condition, disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding that may affect the interpretation of the results, or which might contribute substantially to the patient's experience of study burden (such as non-suppressible claustrophobia).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: ⁶⁸Ga-FAPI-46; ⁶⁸Ga-FAPI-46 will be used as a diagnostic tracer for PET/CT to image peritoneal tumor cells.	Drug: ⁶⁸Ga-FAPI-46; All patients will be administered with 1.5 MBq/kg ⁶⁸Ga-FAPI-46. ⁶⁸Ga-FAPI-46 will be injected intravenously followed by a flush injection of 10 mL of saline following routine procedures.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Accuracy of ⁶⁸Ga-FAPI	To investigate the accuracy of the ⁶⁸Ga-FAPI PET/CT for peritoneal response evaluation in patients with peritoneal metastases that are treated with any form of repeated IP chemotherapy. The accuracy will be calculated as the sensitivity and specificity of the ⁶⁸Ga-FAPI PET/CT with clinical assessment during MTB and/or histopathological outcome at second laparoscopy as a reference standard.	18 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tumor response to IP chemotherapy	To measure the tumor response to IP chemotherapy. The absolute change in peritoneal tumor size or volume as measured by imaging before and after treatment.	18 weeks

Collaborators and Investigators

• Sponsor: Erasmus Medical Center
• Investigators: Principal Investigator: Stijn Koolen, PharmD, PhD, Erasmus Medical Center

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2025
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: May 2, 2025
• First Submitted That Met QC Criteria: May 2, 2025
• First Posted (Actual): May 5, 2025

Study Record Updates

• Last Update Posted (Actual): May 9, 2025
• Last Update Submitted That Met QC Criteria: May 6, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: PET/CT; Intraperitoneal; Peritoneal metastasis; FAPI
• Additional Relevant MeSH Terms: Pathologic Processes; Neoplasms; Neoplastic Processes; Neoplasm Metastasis; Molecular Mechanisms of Pharmacological Action; Radiopharmaceuticals; FAPI-46
• Other Study ID Numbers: 2024-520037-76-00

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No