In order to establish a structure–activity relationship, the binding affinity of the metal-free and natGa-complexes of the conjugates 7, 8, and 9 were determined in the PSMA-positive human prostate cancer cell line LNCaP by a competitive binding assay as previously reported using [177Lu]Lu-PSMA-617 as the radioligand (Stemler et al. 2021). The gene discussed is FOLH1; the disease is prostate cancer.