DPI-4452 is a CAIX-targeting cyclic peptide with a DOTA chelator. DPI-4452 can be chelated with radionuclide for CAIX-expressing tumor PET-CT imaging. DPI-4452 was used to prepare [68Ga]Ga-DPI-4452, which is a first-in-class carbonic anhydrase IX-binding radiolabeled peptide, and is the imaging agent of a theranostic pair with [177Lu]Lu-DPI-4452, developed for selecting and treating patients with carbonic anhydrase IX-expressing tumors. [68Ga]Ga-DPI-4452 showed exceptional tumor uptake in patients with clear cell renal cell carcinoma, with very high tumor-to-background ratios and no significant adverse events, suggesting potential diagnostic and patient selection application.
