Indium-diethylenetriaminepentaacetic acid (In-DTPA)

Indium-diethylenetriaminepentaacetic acid (In-DTPA) is a stable coordination complex formed by the chelation of an indium ion with diethylenetriaminepentaacetic acid (DTPA). In the field of nuclear medicine, it serves as a synthetic hapten used in pre-targeted radioimmunotherapy (PRIT) and diagnostic imaging (Goldenberg et al., 2006). This strategy utilizes a bispecific antibody that binds both a tumor-associated antigen and the In-DTPA complex. The antibody is administered first to localize at the tumor site, followed by the administration of radiolabeled In-DTPA, which is then captured by the antibody (Barbet et al., 1999). This method significantly improves the therapeutic index by allowing rapid clearance of the radioactive component from the blood, thereby reducing off-target radiation to healthy tissues like the bone marrow (Kraeber-Bodéré et al., 2006). While In-DTPA does not possess intrinsic biological activity, it acts as a critical artificial target for engineered antibodies in the treatment and detection of various cancers, including medullary thyroid and colorectal carcinomas.

Other names

Indium-DTPAIn-DTPA haptenIndium-111 pentetate111In-DTPAIndium-diethylenetriamine pentaacetic acid

Acts as a synthetic hapten in a pre-targeting system where a bispecific antibody captures the radiolabeled chelate at the tumor site.