Study Aiming to Compare the Plasma Exposure of the Payload (Free-DXd) in Patients Treated by T-DXd for Locally Advanced or Metastatic Breast Cancer According to Their BMI.

Not Applicable

Not yet recruiting

• Conditions: Locally Advanced or Metastatic Breast Cancers
• Interventions: Biological: Pharmacokinetics blood samples

• Registration Number: NCT07195344
• Lead Sponsor: Institut Claudius Regaud

Brief Summary

This is a multicenter, prospective, non-randomized, open-label, pharmacokinetic study, aiming to compare the plasma exposure of the payload (free-DXd) in patients treated by T-DXd for locally advanced or metastatic breast cancer according to their BMI.

The primary objective is to compare plasma exposition of the payload (free-DXd) between overweight or obese (BMI\>25) and normal weight (BMI≤25) breast cancer patients during the first 3 cycles of Trastuzumab-Deruxtecan (T-DXd).

A total of 210 patients will have to be enrolled in this study with the following repartition:

N = 105 patients with a BMI ≤ 25 (normal weight patients). N = 105 patients with a BMI \> 25 (overweight or obese patients) with at least 30 obese patients (BMI\>30).

Detailed Description

Not available

Study Timeline

• Status Verified: 2025-09
• Study First Submitted: 2025-09-11
• Study First Submitted QC: 2025-09-19
• Last Update Submitted: 2025-09-19
• Study First Posted: 2025-09-26
• Last Update Posted: 2025-09-26
• Study Start: 2025-10-01
• Primary Completion: 2029-10
• Study Completion: 2029-10-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 210

Inclusion Criteria

1. Women (or men) aged ≥ 18 years on the day of signing the informed consent with histologically proven breast cancer.

2. Metastatic or locally advanced breast cancer with overexpression/amplification HER2 (IHC +++ or ++ and positive-hybridation in situ) or low HER2 expression (IHC + or ++ and negative-hybridation in situ) and may be ultra-low (in first line, in case of approval).

3. Patient eligible for Trastuzumab-Deruxtecan (T-DXd).

4. Concomitant administration of pertuzumab may be accepted in case of approval in first line for HER2- overexpressed/amplified locally advanced or metastatic breast cancer.

5. Female subjects of childbearing potential must have a negative pregnancy test within 72 hours prior to receiving the first dose of study treatment.

6. Female subjects of childbearing potential must be willing to follow at least one method of contraception or be surgically sterile, or abstain from heterosexual activity for the duration of the study and until 7 months after the last dose of study treatment. Subjects of childbearing potential are those who have not been surgically sterilized and who had menstruation in the last 12 months.

   Note: Abstinence is acceptable if it is the subject's usual lifestyle and preferred method of contraception.

7. Male subjects must agree to use at least one method of contraception for the duration of the study and until 4 months after the last dose of study treatment.

   Note: Abstinence is acceptable if it is the subject's usual lifestyle and preferred method of contraception.

8. Signed written informed consent.

9. Patient able to participate and willing to give informed consent prior performance of any study-related procedures and to comply with the study protocol.

10. Patient affiliated to a Social Health Insurance in France.

Exclusion Criteria

1. Peripheral venous access making blood samples difficult.
2. Patients unable to receive T-DXd treatment at a dose of 5.4 mg/kg in cycle 1 (whatever the reason)
3. Patients with known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin or squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer.
4. Patients with any other significant medical, psychiatric, or surgical condition, currently uncontrolled by treatment, which may interfere with completion of the study.
5. Patient pregnant, or breast-feeding.
6. Any psychological, familial, geographic or social situation, according to the judgment of investigator, potentially preventing the provision of informed consent or compliance to study procedure.
7. Patient who has forfeited his/her freedom by administrative or legal award or who is under legal protection (curatorship and guardianship, protection of justice).
8. Concurrent participation in an experimental drug study.
9. Patient with a known history of hypersensitivity to the active substance of T-DXd or to any of the excipients listed in the SmPC of T-DXd.
10. Patient with severe hepatic impairment defined by TGO and/or TGP > 5 x ULN and Total bilirubin > 1.5 x ULN.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Patient with locally advanced or metastatic breast cancer starting T-DXd as standard treatment	Pharmacokinetics blood samples	-

Primary Outcome Measures

Name	Time	Method
Primary Outcome Measure	From the 1st cycle of T-DXd (C1D1) to the end of the 3rd cycle of T-DXD (each cycle is 21 days) treatment or until an event (interruption or dose concession for toxicity) if it occurs before the 3rd cycle.	Plasma exposure of free-DXd (payload) will be measured by the cumulative AUC (Area under the concentration vs. time curve) over the first 3 cycles or until an event (interruption or dose concession for toxicity) divided by the number of corresponding cycles.; These AUCs will be determined by Bayesian estimation (Posthoc values) using a non-linear mixed-effects approach.

Secondary Outcome Measures

Name	Time	Method
Safety: toxicities will be assessed using the NCI-CTCAE Version 5.0.	From enrollment to the end of patient participation up to 24 months after inclusion
Efficacy: Progression Free Survival (PFS)	From inclusion until progression or death up to 24 months after inclusion	Progression Free Survival (PFS) is defined as the time from inclusion until progression or death; patients alive and without documented progression at last follow-up news are censored at this date or at initiation of new anticancer treatment (if applicable).
Secondary pharmacokinetic criteria	From C1D1 to definitive stop of T-DXd treatment up to 24 months after inclusion	A population PK model will be performed to quantify the impact of several patient characteristics: morphological data (weight, height, BMI, lean mass, etc.), biological data (inflammation markers, albuminemia, liver enzymes, etc.), demographic data (age), on the PK parameters (elimination clearance, volume of distribution) of T-DXd and free-DXd.
Body composition parameters	From enrollment to tumor assessment before C9D1 at 6 months of T-DXd treatment (each cycle is 21 days).	Skeletal muscle mass index or density and lean body mass before treatment initiation and during the active treatment phase (at 3 months tumor assessment before C5D1 and at 6 months; tumor assessment before C9D1) using the "Cassandra" algorithm.

Trial Locations

Locations (9)

Institut de Cancérologie de l'Ouest - Site Angers; 🇫🇷 Angers, France

Centre Georges François Leclerc; 🇫🇷 Dijon, France

Institut Paoli Calmettes; 🇫🇷 Marseille, France

CHU de Nîmes; 🇫🇷 Nîmes, France

Institut Curie - Site Paris; 🇫🇷 Paris, France

Centre Eugène Marquis; 🇫🇷 Rennes, France

Institut de Cancérologie de l'Ouest - Site Saint Herblain; 🇫🇷 Saint-Herblain, France

Centre Paul Strauss; 🇫🇷 Strasbourg, France

IUCT-O; 🇫🇷 Toulouse, France