99mTc-3PRGD2 SPECT/CT in Breast Cancer Patients

Integrin αvβ3 is an important member of integrin receptor family and expressed preferentially on the activated endothelial cells of angiogenesis and some types of tumor cells, but not or very low on the quiescent vessel cells and other normal cells. Therefore, the integrin αvβ3 receptor is becoming a valuable target for diagnosis and response evaluation of malignant tumors.

The tri-peptide sequence of arginine-glycine-aspartic acid (RGD) can specifically bind to the integrin αvβ3 receptor. Accordingly, a variety of radiolabeled RGD-based peptides have been developed for non-invasive imaging of integrin αvβ3 expression via single photon emission computed tomography (SPECT)or positron emission tomography (PET). Among all the RGD radiotracers studied, several RGD monomers have been investigated in clinical trials, and the preliminary results demonstrated specific imaging of various types of tumors, and the tumor uptake correlated well with the level of integrin αvβ3 expression. Recently, several RGD dimeric peptides with PEG linkers have been studied. The new types of RGD peptides showed much higher in vitro integrin αvβ3-binding affinity than the single RGD tri-peptide sequence, and importantly, they exhibited significantly increased tumor uptake and improved in vivo kinetics in animal models. As a representative, 99mTc-3PRGD2 could be easily prepared and exhibited excellent in vivo behaviors in animal models. No adverse reactions are observed in animal models to date.

For the further interests in clinical trial of 99mTc-3PRGD2, an open-label SPECT/CT (single photon emission computed tomography / computed tomography) study to investigate 99mTc-3PRGD2 SPECT/CT in diagnosis and efficacy evaluation of breast cancer. A single dose of nearly 0.3 mCi/kg body weight 99mTc-3PRGD2 ( ≤ 20 µg 3PRGD2) will be intravenously injected into the patients. Visual and semiquantitative method will be used to assess the whole-body planar and lesions SPECT/CT images. Adverse events will also be observed in the patients.

Diagnostic group：

Inclusion criteria

• Males and females, ≥20 years old.
• Part of lesion CT and/or 18F-FDG PET/CT and/or MRI and/or Doppler Ultrasound and/or Mammography diagnosis in suspicion of primary or recurrent breast cancer.
• The above cancers will be histologically confirmed or results of histology will be available.

Exclusion criteria

• Females planning to bear a child recently or with childbearing potential.
• Known severe allergy.
• Inability to lie still for the entire imaging time because of cough, pain, etc.
• Inability to complete the needed examinations due to severe claustrophobia,radiation phobia, etc.
• Concurrent severe and/or uncontrolled and/or unstable other medical disease that, in the opinion of the Investigator, may significantly interfere with study compliance.

Efficacy evaluation group:

Inclusion criteria

• Males and females, ≥20 years old.
• Firstly and definitely diagnose with malignant tumors ,and prepare to chemotherapy (including neoadjuvant chemotherapy) or radiotherapy.
• There are available lesions for assessment during the trial.
• Part of lesion CT and/or 18F-FDG PET/CT and/or MRI and/or Doppler Ultrasound and/or Mammography examination before treatment, the mid tern treatment, post-treatment( three months after the initial treatment) are available.

Exclusion criteria

• Females planning to bear a child recently or with childbearing potential.
• Known severe allergy or hypersensitivity to IV radiographic contrast.
• Inability to lie still for the entire imaging time because of cough, pain, etc.
• Inability to complete the needed examinations due to severe claustrophobia, radiation phobia, etc.
• Concurrent severe and/or uncontrolled and/or unstable other medical disease that, in the opinion of the Investigator, may significantly interfere with study compliance.