Pyrrolobenzodiazepine Conjugates Targeted Delivery
Solution Overview
Problem
Current antibody-drug conjugates face challenges in achieving maximal efficacy with minimal toxicity due to non-selective delivery of cytotoxic agents, with many cytotoxic drugs becoming inactive or less active when conjugated to large antibodies or protein receptor ligands, leading to unwanted toxicity in normal cells.
Innovation Solution
Development of pyrrolobenzodiazepine (PBD) compounds connected through a labile linker to a cell binding agent, such as an antibody, allowing for targeted and controlled release of the active PBD compound, ensuring no residual linker affects reactivity and enabling efficient cytotoxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cytotoxic drugs are conjugated to large antibodies or protein receptor ligands to achieve targeted delivery, then delivery specificity to tumor sites is improved, but the cytotoxic activity of the drug is reduced and unwanted toxicity in normal cells increases
Solution Approach 1:
The antibody-drug conjugate is segmented into distinct functional components: the antibody portion for targeted delivery to tumor sites, the linker portion for controlled release, and the cytotoxic PBD drug portion. This segmentation allows each component to perform its specific function optimally while minimizing interference between them.
Solution Approach 2:
A labile linker acts as an intermediary between the antibody and the cytotoxic PBD compound. This linker is designed to be stable during circulation but becomes labile intracellularly, enabling controlled release of the active drug. The linker structure includes a trigger mechanism that activates upon intracellular delivery, ensuring the cytotoxic agent is released only after reaching the target cell.
2Productivity
If a labile linker is used to enable controlled release of the PBD compound, then intracellular delivery efficiency is improved, but the complexity of the conjugate structure increases
Solution Approach 1:
The linker is pre-configured with a trigger mechanism that is activated upon intracellular delivery. This preliminary setup ensures that the cytotoxic PBD compound is released automatically and efficiently once inside the target cell, without requiring additional external intervention. The trigger mechanism is designed to activate specifically under intracellular conditions, ensuring timely drug release.
3Object-generated harmful factors
If the PBD compound is delivered to tumor sites with minimal toxicity to normal cells, then treatment efficacy is improved, but the selectivity of delivery must be maintained
Solution Approach 1:
The conjugate is designed with local quality differentiation: the antibody portion provides tumor-specific targeting through its binding affinity for tumor-associated antigens, while the linker portion provides controlled release characteristics specific to the intracellular environment. This local quality approach ensures that the cytotoxic PBD compound is delivered selectively to tumor cells while minimizing exposure to normal cells.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The PBD compound is effectively delivered to tumor sites with minimal toxicity to normal cells, maintaining specific binding properties and ensuring intracellular delivery, thereby enhancing cancer treatment efficacy while reducing side effects.
Implementation Method 1
The linker is a labile linker, and may be an enzyme labile linker
Implementation Method 2
The linker is present in the bridge linking the monomer PBD units of the dimer
Implementation Method 3
Some pyrrolobenzodiazepines (PBDs) have the ability to recognise and bond to specific sequences of DNA
Implementation Method 4
Their ability to form an adduct in the minor groove, enables them to interfere with DNA processing
Implementation Method 5
The cell binding agent is preferably an antibody
Data Source
Figure 1a~1b
Figure 2~3
Figure 4~5
AI summary
Conjugates and compounds for making conjugates which are PBD molecules linked via the N10 position are disclosed, along with the use of the conjugates for treating proliferative diseases, including cancer.