Modular self assembly disassembly (SADA) technologies

A method of treating or diagnosing cancer in a subject, comprising:

• a. providing a composition comprising a conjugate comprising a self-assembly disassembly (SADA) polypeptide having an amino acid sequence that is identical to a human homo-multimerizing polypeptide sequence comprising any one of SEQ ID NOs:
• 1, 3, 5, 7, 9, 11, 13, and 15 and having one or more multimerization dissociation constants (KD);
• and a bispecific antibody comprising a first scFv that binds a tumor target and a second scFv that binds a DOTA moiety comprising a radioactive payload, wherein (a) the first scFv is operably linked to the second scFv, (b) the second scFv includes a VH-CDR1 sequence comprising DYGVH (SEQ ID NO:
• 103), a VH-CDR2 sequence comprising VIWSGGGTAYNTALIS (SEQ ID NO:
• 104), a VH-CDR3 sequence comprising RGSYPYNYFDA (SEQ ID NO:
• 105), a VL-CDR1 sequence comprising GSSTGAVTASNYAN (SEQ ID NO:
• 106), a VL-CDR2 sequence comprising GHNNRPP (SEQ ID NO:
• 107), and a VH-CDR3 sequence comprising ALWYSDHWV (SEQ ID NO:
• 108);
• and (c) the second scFv is operably linked to the SADA polypeptide;
• b. administering the composition to a subject that is suffering from or susceptible to cancer;
• and
• c. administering a DOTA chelator comprising a radionuclide.