Radiation Cleaved Drug-Conjugate Linkers Enable Local Payload Release

Area of Science:

• Bioconjugation Chemistry
• Radiochemistry
• Cancer Therapeutics

Background:

• Drug conjugates enhance targeted delivery to solid tumors but face challenges in avoiding healthy tissues, leading to toxicity.
• Payload activity in off-target tissues remains a significant hurdle for current antibody-drug and albumin-drug conjugates.

Purpose of the Study:

• To develop a drug-conjugate linker strategy for spatially localized payload release triggered by ionizing radiation.
• To mitigate toxicity by ensuring therapeutic activity is confined to irradiated tumor sites.

Main Methods:

• Designed a novel linker strategy for drug conjugates (doxorubicin, MMAE) activated by ionizing radiation.
• Investigated payload release under hypoxic conditions, typical of radiotherapy resistance.
• Applied the linker strategy to antibody-drug and albumin-drug conjugates.

Main Results:

• Localized X-ray irradiation (8 Gy) induced 50% drug release under hypoxic conditions.
• Achieved over 2000-fold enhanced cytotoxicity of MMAE upon irradiation in conjugate applications.
• Demonstrated proof-of-principle for localized drug delivery using antibody- and albumin-drug conjugates.

Conclusions:

• Ionizing radiation can be effectively utilized as a trigger for spatially controlled cancer drug delivery.
• This strategy offers a promising approach to enhance therapeutic efficacy while minimizing systemic toxicity.
• The developed linker system shows potential for improving the safety and effectiveness of cancer therapies.