PSMA-reactive NB7 single domain antibody fragment: A potential scaffold for developing prostate cancer theranostics.

Single domain antibody fragments (sdAbs) are an appealing scaffold for radiopharmaceutical development due to their small size (~15 kDa), high solubility, high stability, and excellent tumor penetration. Previously, we developed NB7 sdAb, which has very high affinity for an epitope on PSMA that is different from those targeted by small molecule PSMA inhibitors. Herein, we evaluated NB7 after radioiodination using [*I]SGMIB (1,3,4-isomer) and iso-[*I]SGMIB (1,3,5-isomer), as well as their [*I]SGMIB, iso-[*I]SGMIB, [ All NB7 radioconjugates bound specifically to PSMA with dissociation constants, K NB7 radioconjugates exhibited good accumulation in PSMA-positive xenografts with rapid clearance from kidney and other normal tissues. We conclude that NB7 is a potentially useful scaffold for developing PSMA-targeted theranostics with different characteristics than current small molecule and antibody-based approaches.

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Déclaration de conflit d'intérêts

Declaration of competing interest LR and NP have filed a patent application that includes the NB7 single domain antibody fragment. The authors declare that they have no other known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.