Alpha-emitting complexes

A tissue-targeting complex consisting of

• a tissue targeting moiety selected from antibodies, antibody constructs, fragments of antibodies, constructs of fragments or a mixture thereof, peptide, amino acid, steroidal or non-steroidal hormone, folate, estrogen, testosterone or biotin,
• an octadentate hydroxypyridinone-containing ligand, and
• an ion of an alpha-emitting 227-thorium radionuclide, said octadentate ligand consisting of
• four independently selected chelating moieties of formula I
• a linker moiety for each of said four chelating moieties, wherein each of said linker moieties links one of said four chelating moieties to another, to a template group, or to a backbone moiety, and
• a coupling moiety which links said four chelating moieties to the tissue targeting moiety;
• wherein R1 is selected from the group consisting of H, a hydrocarbyl, OH, O-hydrocarbyl, SH, a S-hydrocarbyl group, the linker moiety, and the coupling moiety;
• groups R4 to R6 are each independently selected from the group consisting of H, OH, a hydrocarbyl group, the linker moiety, and the coupling moiety;
• and R3 is OH and R2 is ═O.

A kit comprising a tissue targeting complex consisting of

• a tissue targeting moiety selected from antibodies, antibody constructs, fragments of antibodies, constructs of fragments or a mixture thereof, peptide, amino acid, steroidal or non-steroidal hormone, folate, estrogen, testosterone or biotin,
• an octadentate hydroxypyridinone-containing ligand, and
• an ion of an alpha-emitting 227-thorium radionuclide
• said octadentate ligand consisting of four independently selected chelating moieties of formula I
• a linker moiety for each of said four chelating moieties, wherein each of said linker moieties links one of said four chelating moieties to another, to a template group, or to a backbone moiety, and
• a coupling moiety which links said four chelating moieties to the tissue targeting moiety;
• wherein R1 is selected from the group consisting of H, a hydrocarbyl, OH, O-hydrocarbyl, SH, a S-hydrocarbyl group, the linker moiety, and the coupling moiety;
• groups R4 to R6 are each independently selected from the group consisting of H, OH, a hydrocarbyl group, the linker moiety, and the coupling moiety;
• and R3 is OH and R2 is ═O.

A tissue-targeting complex consisting of

• a tissue targeting moiety selected from antibodies, antibody constructs, fragments of antibodies, constructs of fragments or a mixture thereof, peptide, amino acid, steroidal or non-steroidal hormone, folate, estrogen, testosterone or biotin,
• an octadentate hydroxypyridinone-containing ligand, and
• an ion of an alpha-emitting 227-thorium radionuclide,
• said octadentate ligand consisting of formula IIIa
• wherein each RN is independently a substituted or unsubstituted hydrocarbyl group;
• and
• wherein each RL is independently a linker moiety and T is a template group by which the four chelating hydroxypyridinone moieties are joined to each other;
• and
• a coupling moiety which links said formula IIIa to said tissue targeting moiety.

A tissue-targeting complex consisting of

• a tissue targeting moiety selected from antibodies, antibody constructs, fragments of antibodies, constructs of fragments or a mixture thereof, peptide, amino acid, steroidal or non-steroidal hormone, folate, estrogen, testosterone or biotin,
• an octadentate hydroxypyridinone-containing ligand, and
• an ion of an alpha-emitting 227-thorium radionuclide, said octadentate ligand consisting of formula IVa
• wherein each RN is independently a substituted or unsubstituted hydrocarbyl group;
• and
• wherein each RL is independently a linker moiety and each RB is independently a backbone moiety by which the four chelating hydroxypyridinone moieties are joined to each other;
• and
• a coupling moiety which links said formula IV to said tissue targeting moiety.