⁹⁰Y-DOTA-biotin consists of a radioactive substance ( yttrium-90) complexed by a chelating agent ( DOTA), which in turn is attached to the vitamin

biotin Biotin (or vitamin B7) is one of the B vitamins. It is involved in a wide range of metabolic processes, both in humans and in other organisms, primarily related to the utilization of fats, carbohydrates, and amino acids. The name ''biotin'', bor ...

via a chemical linker. It is used experimentally in pretargeted radioimmunotherapy. Animal studies have been conducted as well as clinical studies in humans. In pretargeted radioimmunotherapy, two or three medications are applied in succession. At first, an antibody-drug conjugate is administered, which consists of a monoclonal antibody designed to target the tumour, and a chemical marker which in the case of DOTA-biotin therapy is one of the proteins

avidin Avidin is a tetrameric biotin-binding protein produced in the oviducts of birds, reptiles and amphibians and deposited in the whites of their eggs. Dimeric members of the avidin family are also found in some bacteria. In chicken egg white, avidin ...

and

streptavidin Streptavidin is a 66.0 (tetramer) kDa protein purified from the bacterium '' Streptomyces avidinii''. Streptavidin homo-tetramers have an extraordinarily high affinity for biotin (also known as vitamin B7 or vitamin H). With a dissociation co ...

. After a time of typically one or two days to let the antibody accumulate in the tumour, a clearing agent may be given to eliminate residues of antibody that are still circulating in the bloodstream; this is especially done in humans. After a further waiting time, the radiotherapy (⁹⁰Y-DOTA-biotin) is administered. Due to the high affinity of biotin to avidin and streptavidin, the radiotherapy accumulates where the antibody is, namely in the tumour, where it delivers its radioactivity. 90Y-DOTA-biotin skeletal

References

Radiopharmaceuticals DOTA (chelator) derivatives {{antineoplastic-drug-stub