Optimization of IEDDA bioorthogonal system: Efficient process to improve trans-cyclooctene/tetrazine interaction

Area of Science:

• Oncology
• Radiochemistry
• Organic Chemistry

Background:

• Antibody pretargeting using inverse electron demand Diels-Alder cycloaddition (IEDDA) is a promising theranostic strategy for solid tumors.
• Clinical translation of IEDDA pretargeting is hindered by the instability of trans-cyclooctene (TCO), which can isomerize to unreactive cis-cyclooctene (CCO).

Purpose of the Study:

• To develop stable trans-cyclooctene (TCO) derivatives for antibody pretargeting.
• To establish efficient synthetic and analytical methods for producing high-purity TCO-modified antibodies.
• To mitigate TCO isomerization to CCO, enhancing IEDDA efficiency.

Main Methods:

• Development of novel synthetic pathways for (PEGylated) TCO derivatives.
• Implementation of analytical techniques for monitoring TCO isomeric purity.
• Establishment of a process to minimize TCO to CCO isomerization prior to antibody functionalization.

Main Results:

• Achieved high isomeric purity of (PEGylated) TCO derivatives.
• Developed reproducible synthetic routes and analytical follow-up.
• Successfully limited TCO isomerization before antibody conjugation, enabling efficient TCO/tetrazine cycloaddition.

Conclusions:

• The developed methods provide stable TCO derivatives crucial for advancing IEDDA pretargeting in radioimmunotherapy.
• This work addresses a critical limitation, paving the way for clinical trials of IEDDA-based cancer theranostics.