A Multicentre, Prospective, Open-label Study With [68Ga]Ga-ABY-025 PET-imaging to Characterize HER2-expression and Explore the Therapy-predictive Value for HER2-antibody Drug Conjugates in Patients With Metastatic Breast Cancer
This is a prospective, multi-center, open-label, exploratory diagnostic phase II imaging trial for patients with metastatic breast cancer with at least one line of systemic therapy. The overarching aim of the HER2-Ex PET trial is to study the role of precision imaging utilizing positron emission tomography (PET) with the HER2-specific tracer \[68Ga\]Ga-ABY-025 (hereafter referred to as HER2-PET) in enhancing treatment planning for patients with metastatic HER2-expressing breast cancer Patients will be allocated based on HER2-status on PET and biopsy. Patients with HER2-expressing lesions in a fresh or archived tumour biopsy will be treated with T-DXd. The study hypothesis is that PET/CT precision imaging with a contemporary HER2-radiotracer (\[68Ga\]Ga-ABY-025) can be used and can lead to a potentially better identification of patients who benefit from T-DXd treatment, thereby achieving improved treatment responses as well as fewer side effects. This study's diagnostic approach provides a more individualized treatment strategy. Additionally, this study can potentially give us a better biological understanding of HER2-expressing mBC.
• Female patients age ≥18 years.
• Metastatic or locally advanced breast cancer with disease progression after ≥ 1 line of chemotherapy in the palliative setting, or with disease relapse within six months after completion of (neo-) adjuvant chemotherapy.
• The patient must be able and willing to provide written consent to participate in the study.
• At least one metastatic lesion ≥ 10 mm is available for biopsy
• o Exception can be made when a recent biopsy is available (no more than 12 months old and without exposition to HER2-targeted therapy or local radiotherapy to the specific lesion).
• At least one additional metastatic index lesion ≥ 10 mm for evaluation of treatment effect (according to RECIST v1.1)
• WHO performance status ≤ 2.
• Expected survival \> 12 weeks.
• Contraceptives: Females of child-bearing potential must agree to use adequate contraception prior to study entry, for the duration of the study treatment phase and for six months after the last dose of \[68Ga\]Ga-ABY-025. Examples of contraceptive methods with a failure rate of \< 1% per year include bilateral tubal ligation, male sterilization, established, proper use of hormonal contraceptives that inhibit ovulation, hormone- releasing intrauterine devices (IUDs), and copper IUDs. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or postovulation methods) and withdrawal are not acceptable methods of contraception. Women must refrain from donating eggs during this same period. Should a female become pregnant or suspect she is pregnant while participating in this study, she should inform her study physician immediately. If a female participant is of child-bearing potential (females are considered not of childbearing potential if they are at least one year postmenopausal and/or surgically sterile), she must have a documented negative serum Pregnancy testing prior to each administration of the IMP is obligatory.