A New [⁶⁸Ga]Ga-HBED-CC-Bisphosphonate as a Bone Imaging Agent

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Oncology

Background:

• Positron emission tomography (PET) imaging is crucial for cancer diagnosis and treatment monitoring.
• Targeting bone metastasis with radiolabeled compounds is an active area of research.
• Current bone imaging agents like Na[¹⁸F]F often require a nearby cyclotron.

Purpose of the Study:

• To develop and evaluate a novel ⁶⁸Ga-labeled bisphosphonate ([⁶⁸Ga]Ga-HBED-CC-BP) as a PET imaging agent for bone metastasis.
• To assess the labeling efficiency, stability, and bone-targeting properties of the new agent.
• To compare its performance with existing bone imaging agents.

Main Methods:

• Synthesis of the ⁶⁸Ga-labeled ligand HBED-CC-BP.
• Rapid complexation of ⁶⁸Ga with the ligand using a ⁶⁸Ge/⁶⁸Ga generator.
• In vitro stability assays and hydroxyapatite binding affinity tests.
• In vivo biodistribution and MicroPET imaging studies in normal mice and rats.

Main Results:

• High labeling yield (>95%) achieved rapidly at room temperature.
• The resulting [⁶⁸Ga]Ga-HBED-CC-BP demonstrated excellent in vitro and in vivo stability.
• Significant bone uptake and retention observed in animal models, comparable to Na[¹⁸F]F.
• An automated synthesis module was developed for reproducible clinical dose production.

Conclusions:

• [⁶⁸Ga]Ga-HBED-CC-BP is a promising bone-seeking PET imaging agent.
• It offers a convenient, cyclotron-independent alternative to Na[¹⁸F]F for bone metastasis imaging.
• Clinical trials are underway following FDA approval (IND #129870).