Amatoxin Cyclic Peptide ADC Linker Design for Plasma Stability
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Solution Overview
Problem
Current antibody-drug conjugates (ADCs) face challenges in delivering potent RNA polymerase inhibitors to cancer cells while maintaining stability in plasma, which affects the therapeutic window and safety, with limited options for cytotoxic payloads beyond maytansinoids, auristatins, and calicheamycins.
Innovation Solution
Development of novel cytotoxic cyclic peptides analogs of alpha-amanitin and beta-amanitin, specifically modified at the 7′ position of the indole ring with linker components, for use in ADCs to target and inhibit RNA polymerase in cancer cells, enhancing stability and delivery efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amatoxins are used as cytotoxic payloads in ADCs, then potency against RNA polymerase is improved, but stability in plasma deteriorates
Solution Approach 1:
A plasma-stable linker is introduced as an intermediary component between the amatoxin payload and the antibody. This linker maintains the amatoxin's RNA polymerase inhibitory activity while protecting it from plasma degradation, thereby resolving the contradiction between potency and stability.
Solution Approach 2:
The ADC is constructed as a composite system combining the amatoxin cyclic peptide, a plasma-stable linker, and a target-specific antibody. This composite structure allows each component to contribute its specific properties: the amatoxin provides potency, the linker provides stability, and the antibody provides targeting accuracy.
2Stability of the object's composition
If conventional ADC payloads are used, then plasma stability is improved, but therapeutic efficacy against cancer cells deteriorates
Solution Approach 1:
The chemical structure of the payload is changed from conventional ADC agents to amatoxin cyclic peptides, which have superior RNA polymerase inhibitory activity. By modifying the payload type while maintaining plasma stability through the use of a stable linker, the therapeutic efficacy is enhanced without sacrificing stability.
3Ease of manufacture
If amatoxins are conjugated to antibodies without plasma-stable linkers, then ease of manufacture is improved, but therapeutic window and safety deteriorate
Solution Approach 1:
A plasma-stable linker serves as a mediating component that can be incorporated into the conjugation process with minimal additional complexity. This linker protects the amatoxin from premature release in plasma, thereby expanding the therapeutic window and improving safety while maintaining ease of manufacture.
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 novel cytotoxic cyclic peptides effectively inhibit cell proliferation and are stable in plasma, improving the therapeutic window and safety of ADCs by targeted delivery of potent RNA polymerase inhibitors to cancer cells.
Implementation Method 1
Amatoxins are potent and selective inhibitors of RNA polymerase II, a vital enzyme in the synthesis of messenger RNA (mRNA), microRNA, and small nuclear RNA (snRNA). By inhibiting the synthesis of mRNA, Amatoxins thereby stop cell metabolism by inhibiting transcription and protein biosynthesis
Implementation Method 2
ADCs include an antibody selected for its ability to bind to a cell targeted for therapeutic intervention, linked to a drug selected for its cytostatic or cytotoxic activity. Binding of the antibody to the targeted cell thereby delivers the drug to the site where its therapeutic effect is needed
Data Source
AI summary
The invention disclosed herein relates to cytotoxic cyclic peptides of Formula (I), methods of inhibiting RNA polymerase with such cyclic peptides, immunoconjugates comprising such cyclic peptides (i.e Antibody Drug Conjugates), pharmaceutical compositions comprising such cyclic peptides immunoconjugates, compositions comprising such cyclic peptides immunoconjugates with a therapeutic co-agent and methods of treatment using such cyclic peptides immunoconjugates: