NCT05955833

89Zr-DFO*-Trastuzumab PET in Patients With Gastric or Breast Cancer - a Pilot Study

• Status: Unknown
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 6 (estimated)
• Sponsor: Amsterdam UMC, location VUmc · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The goal of this clinical trial is to test a new PET tracer in patients with HER2-positive breast or gastric cancer. This tracer is made of radioactively labeled trastuzumab, and can show where HER2 is present in the body using a PET-scan. For this research, the investigators make PET-scans in people with HER2-positive, metastasized breast- or gastric cancer. The investigators will investigate if the new HER2-tracer correctly shows all tumor lesions. In the future, this method may be useful to help predict who will benefit from certain HER2-directed therapies. Participants will be injected with the radioactive tracer once. After injection, participants will undergo 3 PET-scans. Each PET-scan will take a maximum of 60 minutes. The PET-scans are on separate days within a week after injection of the tracer (e.g. 1 day, 2 days and 4 days after injection). Furthermore, the investigators will take 7 blood samples (5 mL each). Participants are not required to stay at the hospital. The first 3 participants will undergo an extra PET-scan 1 - 2 hours after injection. The amount of radioactivity injected will be 37 MBq (± 10%).

Detailed description

Positron emission tomography (PET) imaging with 89Zr-labeled trastuzumab can potentially discriminate between human epidermal growth factor 2 (HER2) positive and HER2-negative lesions in cancer patients. The obvious advantage over tumor biopsies is that PET imaging provides an overview regarding the heterogeneity of HER2-positivity of all lesions in the patient noninvasively at any given time. The use of a tracer with high specificity and low background signal is critical for accurately identifying positive lesions in patients. Earlier studies in patients with HER2-positive (HER2+) breast cancer and gastric cancer using 89Zr-trastuzumab led to the identification of HER2-positive tumor lesions. However, also lesions were missed and false-positive lesions were seen. Previous work has shown that organs like liver and spleen have significant uptake of 89Zr-trastuzumab. In addition, HER2-directed therapy is most effective in HER2-positive tumors, which are defined as immunohistochemistry (IHC) HER2 expression 3+ or HER2 2+ with gene amplification. Tumors with IHC 0, 1+ or 2+ without amplification are considered HER2-negative. To be able to discriminate between these expression levels with PET imaging, an excellent signal to background ratio is required. Recently, an improved 89Zr-labeled trastuzumab tracer has been developed using a different chelator for 89Zr binding, DFO\*, which further improves stability of the 89Zr-labeled trastuzumab tracer. 89Zr-DFO\*-trastuzumab preclinically shows improved specificity in uptake of tumor lesions while non-tumor related uptake in bone, liver and spleen is reduced, potentially improving the discrimination of HER2-positive tumor lesions in patients. The investigators hypothesize that the improved 89Zr-DFO\*-trastuzumab tracer will lead to a reduced background uptake and thus a better discrimination of HER2-positive tumor lesions.

Conditions

• Breast Cancer
• Metastatic Breast Cancer
• HER2-positive Breast Cancer
• Gastric Cancer
• Metastatic Gastric Cancer
• HER2-positive Gastric Cancer

Interventions

Type	Name	Description
DIAGNOSTIC_TEST	89Zr-DFO*-trastuzumab PET scan	Patients will be administered 37 MBq 89Zr-DFO\*-trastuzumab and undergo 3 PET scans on the total body PET scanner at day 1, day 2 and day 4 post-injection (p.i.). The first 3 patients will undergo an additional PET 1-2 h p.i. for dosimetry purposes. Three scans are needed for PK modelling and day 4 p.i. is chosen because it is the same time point as in historical controls. Blood samples for (radioactive) PK analysis will be taken at 10 min, 30 min, 1 h and 2 h p.i., and at every PET scan.

Timeline

• Start date: 2023-06-26
• Primary completion: 2024-04-30
• Completion: 2024-04-30
• First posted: 2023-07-21
• Last updated: 2023-07-21

Locations

1 site across 1 country: Netherlands