Influence of the linker on the biodistribution and catabolism of actinium-225 self-immolative tumor-targeted isotope generators.

Current limitations to applications of monoclonal antibody (mAb) targeted isotope generators in radioimmunotherapy include the low mAb labeling yields and the nonspecific radiation of normal tissues by nontargeted radioimmunoconjugates (RIC). Radiotoxicity occurs in normal organs that metabolize radiolabeled proteins and peptides, primarily liver and kidneys, or in radiosensitive organs with prolonged exposure to the isotope from the blood, such as the bone marrow. Actinium-225 nanogenerators also have the problem of released agar-emitting daughters.

Immunoreactivity assay for alpha-particle emitting monoclonal antibody constructs.

Clinical trials using alpha-particle radiolabeled antibodies require a rapid and reproducible assay of the immunoreactivity of drugs. While live cell assays are typically used to determine the immunoreactive drug fraction, a fixed cell assay may replace the traditional live cell assay and offer the advantages of rapidity, easy availability and consistency for qualifying drugs for preclinical or clinical studies. We have identified optimal cell fixation and immunoreactivity assay conditions and have validated them by performing the fixed-cell assay in clinical trials.