gallium-68 NOTA-GPA33 nanobody

Gallium-68 NOTA-GPA33 nanobody is a radiopharmaceutical diagnostic agent designed for Positron Emission Tomography (PET) imaging of tumors expressing Glycoprotein A33 (GPA33), primarily colorectal cancer. The agent consists of a humanized camelid-derived single-domain antibody fragment (nanobody or VHH) with high affinity for GPA33, a cell surface glycoprotein overexpressed in more than 95% of colorectal carcinomas. The nanobody is conjugated to the bifunctional chelator NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid) and labeled with the positron-emitting isotope Gallium-68. Due to its small molecular size (approximately 15 kDa), the nanobody exhibits rapid systemic clearance and deep tumor penetration, allowing for high-contrast imaging at early time points (e.g., 1-2 hours post-injection) compared to conventional full-length antibodies. This kinetic profile is well-matched to the 68-minute physical half-life of Gallium-68, facilitating efficient clinical workflows for staging colorectal cancer and selecting patients for GPA33-targeted therapies.

Other names

68Ga-labeled GPA33 nanobody68Ga-NOTA-A33-nanobodygallium-68 NOTA-hA33-VHHgallium68 NOTA-hA33-VHHgallium 68 NOTA-hA33-VHH