PERCIST Evaluation of Trastuzumab Deruxtecan in the Treatment of HER2 Low Breast Cancer (PERPETUAL)

The development of trastuzumab deruxtecan (T-DXd), an anti-HER2 conjugated antibody, has changed the therapeutic landscape of breast cancer. Anti-HER2 molecules were previously used exclusively in cases of HER2-positive breast cancer (IHC HER2 3+ or HER2 2+ with amplified FISH/SISH).

Since a couple of years, T-DXd is becoming a reference treatment in patients with low HER2 breast cancer (IHC 1+ or 2+ with non-amplified FISH/SISH) after hormone therapy and at least one line of chemotherapy. The results of the DB04 trial revealed that T-DXd increased progression-free survival and overall survival compared to investigator's choice chemotherapy, in HER2 low breast cancers patients after one or two previous lines of chemotherapy (Modi, S. et al., 2022).

In several trials, T-DXd validation was done thanks to radiological evaluation based on conventional imaging, computed tomography scan (CT-scan) with or without contrast dye injection and bone scintigraphy.

18F-Fluorodeoxyglucose positron emission tomography coupled with computed tomography (18F-FDG PET-CT) represents a major tool for diagnosis, staging, and therapeutic follow-up in oncology.

It was demonstrated that 18F-FDG PET-CT is more sensitive in detecting metastatic disease progression in HER2-positive breast cancer patients treated with trastuzumab and pertuzumab or trastuzumab and lapatinib (Ma, G. et al., 2023 et Lin, N. U. et al., 2015). Moreover, a prospective study investigated the correlation between the response rate defined by 18F-FDG PET-CT and thoraco-abdomino-pelvic CT-scan (TAP CT-scan) and the progression-free survival of patients with breast cancer. PET evaluation allowed better identification of responders versus non-responders, with a significant correlation with progression-free survival (Vogsen, M. et al., 2023).

With this study, the investigators aim to determine the role of 18F-FDG PET-CT in evaluating T-DXd treatment in patients with metastatic low HER2 breast cancer. 18F-FDG PET-CT could be an earlier evaluation tool than CT-scan in identifying non-responsive patients; and thus, avoid continuing an expensive treatment with an unfavorable toxicity profile, which could worsen both patient prognosis and quality of life.

Study Overview

• Status: Not yet recruiting
• Conditions: Metastatic Breast Cancer; HER 2 Low-expressing Breast Cancer
• Intervention / Treatment: Procedure: TAP CT-scan; Procedure: Bone scintigraphy; Procedure: 18F-FDG PET-CT

Detailed Description

Screening period will last 28 days. Each participant will have baseline evaluation by TAP CT-scan, bone scintigraphy and 18F-FDG PET-CT.

After randomization, patient will start T-DXd treatment according to SOC until progression or toxicity. Patient will be followed by TAP CT-scan and bone scintigraphy (SOC arm) or 18F-FDG PET-CT (experimental arm) every 3 months, until progression or new treatment initiation or death or until 2 years whichever occurs first.

• Study Type: Interventional
• Enrollment (Estimated): 262
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Valérie SARTORI; Phone Number: 33 368767223; Email: v.sartori@icans.eu
• Study Contact Backup: Name: Anne ANTHONY; Phone Number: 33 36876252413; Email: an.anthony@icans.eu

Study Locations

• France
  • Strasbourg, France, 67033
    • ICANS
    • Contact: François SOMME; Phone Number: 33 368766767; Email: f.somme@icans.eu

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Age greater than or equal to 18 years at inclusion
2. Cytological or histological confirmation of the diagnosis of low HER2 breast cancer (IHC 1+ or 2+ with non-amplified FISH/SIS)
3. Metastatic disease according to RECIST 1.1
4. Indication of T-DXd treatment
5. Patient (male or female of childbearing potential) using a highly effective contraceptive method
6. Women of childbearing potential must have a negative pregnancy test within 72 hours before starting treatment
7. Willingness and ability to comply with the visit schedule, treatment regimens, examinations and other procedures planned in the study
8. Patient enrolled in a health insurance plan or beneficiary of such a plan
9. Signed informed consent obtained before inclusion (after giving clear, fair and appropriate information)

Exclusion Criteria:

1. Allergy to contrast dye
2. Contra-indication to PET-CT
3. Any active infection or uncontrolled intercurrent pathology
4. Patient with a life expectancy lower than 3 months
5. Ongoing participation in another clinical trial with an investigational treatment
6. Pregnant or breastfeeding women
7. Persons deprived of their freedom or under guardianship or incapable of giving consent
8. Any psychiatric illness/social situation that may limit compliance with study procedures or prevent the patient from giving written informed consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: SOC arm; Patient will be followed by TAP CT-scan and bone scintigraphy every 3 months, until progression or new treatment initiation or until 2 years whichever occurs first.	Procedure: TAP CT-scan; Patient in the SOC arm will be followed by TAP CT-scan every 3 months, until progression or new treatment initiation or until 2 years whichever occurs first.; Procedure: Bone scintigraphy; Patient in the SOC arm will be followed by bone scintigraphy every 3 months, until progression or new treatment initiation or until 2 years whichever occurs first.
Experimental: Experimental arm; Patient will be followed by 18F-FDG PET-CT every 3 months, until progression or new treatment initiation or until 2 years whichever occurs first.	Procedure: 18F-FDG PET-CT; Patient in the experimental arm will be followed by 18F-FDG PET-CT every 3 months, until progression or new treatment initiation or until 2 years whichever occurs first.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective response rate	Radiological response according to PERCIST 1.0 criteria in experimental arm and RECIST 1.1 criteria in SOC arm. Number of patients who had an objective response at 3 months in both arms. The evaluation is carried out by the investigator.	at 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression-free survival	Progression events will be collected (progression according to PERCIST 1.0 criteria in experimental arm and RECIST 1.1 criteria in SOC arm or death whatever the cause).	Every 3 months until the date of first documented progression or new therapy initiation or date of death or until 2 years, whichever occurs first.
Time until new therapy initiation	Time from inclusion to initiation of new therapy.	Until initiation of a new therapy or until 2 years, whichever occurs first.
Overall survival	The patient's condition (alive, deceased from whatever cause or lost to follow-up) will be collected. Patients alive at the time of analysis will be censored on the date of last contact.	From date of inclusion until the date of death or lost to follow-up or until 2 years, whichever occurs first.
Response duration	Time from date of first documented response (complete or partial response) to date of first subsequent progression or death from any cause.	Every 3 months until the date of first documented progression or new therapy initiation or date of death or until 2 years, whichever occurs first.
Patient Quality of life	Assessment of all dimensions of the European Organization for Research and Treatment of Cancer (EORTC) QLG Core Questionnaire (EORTC QLQ-C30). Difference on specific symptom scales (from 1 = " not at all " to 4 = " very much ", or from 1 = " really bad " to 7 = " excellent ").	Every 3 months until the date of first documented progression or new therapy initiation or date of death or until 2 years, whichever occurs first.

Collaborators and Investigators

• Sponsor: Centre Paul Strauss
• Investigators: Principal Investigator: François SOMME, Institut de cancérologie Strasbourg Europe

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2025
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): September 1, 2030

Study Registration Dates

• First Submitted: August 12, 2025
• First Submitted That Met QC Criteria: August 12, 2025
• First Posted (Actual): August 19, 2025

Study Record Updates

• Last Update Posted (Estimated): September 10, 2025
• Last Update Submitted That Met QC Criteria: September 3, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Breast Cancer; T-DXd; 18F-FDG PET-CT
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms; Molecular Mechanisms of Pharmacological Action; Radiopharmaceuticals; Fluorodeoxyglucose F18
• Other Study ID Numbers: 2024-008

Drug and device information, study documents

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