Pretargeting in radio bio-conjugate therapy: with reference to “rhenium, gold & lutetium as candidate therapy isotopes”

Radiobioconjugate therapy is an emerging modality for Cancer in addition to conventional surgery, chemotherapy & external radio-therapy. The central problem of radio-bioconjugate therapy is the small fraction of radio-bioconjugate localized in the tumour. Pretargeting is one approach to maximize targeting in which an antibody construct, having a dual affinity both for tumour associated antigen as well as for a radio-labeled moiety is first administered followed by the radio-labeled moiety, which may be either biotin or a metal chelate. The relative merits of these are described & Rhenium-Re^186/188, Gold-Au¹⁹⁹ & Lutetium-Lu¹⁷⁷ are suggested as candidate therapy isotopes in such pretargeting approaches.