The Need

The high specificity of antibodies has been utilized to develop numerous technologies, tools and therapeutics, like ADCs and radiopharmaceuticals. Engineered antibody fragments like single-chain variable fragments (scFvs) are starting to see their way into the clinic in BiTEs and CAR T. ScFvs provide benefits such as decreased immunogenicity, easier production, and tunable size and pharmacokinetics; however, there are not as many ways to conjugate or functionalize these fragments as full-length antibodies.

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The Technology

This technology describes the design of scFv fragments with a disulfide-closed (Cys-Cys) cyclic peptide interdomain linker, encoded at the genetic level. In addition to enhancing stability, the cyclic peptide can be engineered to serve a functional purpose in tandem with the antigen binding properties of scFv.

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Advantages and Commercial Applications

Highly modular, the cyclic peptide linker can be engineered and tailored to fit a myriad of different therapeutic or research needs, such as:

• • Improved compound isolation – enables scFv isolation without the use of affinity tags (e.g., His tags), reducing possible immunogenicity, and especially useful for lambda light chain scFvs that do not bind Protein L
  • Bispecific targeting – cyclic peptides against many targets are available, and engineering new ones with phage display or bead-based synthetic approaches is well established
  • Intracellular targeting – cyclic cell-penetrating peptides can enhance crossing of the plasma membrane, opening the way for intracellular drug delivery
  • Enhanced stability – the decreased serum half-life of scFvs can be a pro or con depending on the application. Stability conferred by the cyclic peptide can be utilized to fine tune scFv pharmacokinetics.

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Patents

PCT application filed, see application PCT/US2023/07123