Anti-cKIT Antibody Drug Conjugates for Selective Stem Cell Ablation
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Solution Overview
Problem
Current hematopoietic stem cell transplantation methods are associated with risks such as poor engraftment, immunological rejection, graft-versus-host disease, and toxicity, necessitating improved conditioning and transplantation techniques.
Innovation Solution
Development of anti-cKIT antibody drug conjugates that specifically bind to human cKIT and are linked to cytotoxic agents, allowing for selective delivery and ablation of hematopoietic stem cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If full length anti-cKIT antibodies or F(ab')2 fragments are used, then mast cell degranulation occurs causing adverse reactions, but antibody fragments (Fab or Fab') do not cause degranulation and are safer
Solution Approach 1:
The patent segments the antibody into different fragments (Fab, Fab') that retain cKIT binding capability but lack the Fc region responsible for mast cell degranulation. This segmentation allows selective ablation of hematopoietic stem cells without triggering adverse mast cell reactions.
Solution Approach 2:
The patent extracts and removes the Fc region from the complete antibody, retaining only the antigen-binding Fab or Fab' fragments. This extraction eliminates the harmful Fc-mediated mast cell degranulation while preserving the therapeutic cKIT binding and cytotoxic delivery function.
2Reliability
If conventional conditioning regimens are used, then immunological rejection is prevented, but severe toxicity occurs making treatment contra-indicated for many patients
Solution Approach 1:
The patent uses antibody drug conjugates as intermediaries that selectively deliver cytotoxic agents to cKIT-expressing hematopoietic stem cells. This targeted approach replaces conventional non-selective conditioning regimens, achieving graft acceptance without severe systemic toxicity.
Solution Approach 2:
The patent applies cytotoxic therapy locally to cKIT-positive hematopoietic stem cells through antibody-targeted delivery, rather than systemically as in conventional conditioning. This local quality approach eliminates off-target toxicity while maintaining effective immunosuppression for graft acceptance.
3Reliability
If current conditioning regimens are used, then graft-versus-host disease is prevented, but insufficient amounts can be provided and engraftment is poor
Solution Approach 1:
The patent changes the delivery parameters of cytotoxic agents from non-targeted systemic administration to antibody-targeted selective delivery. This parameter change enables higher effective doses at the target site (improving engraftment) while maintaining safety (preventing GVHD), overcoming the limitations of conventional conditioning.
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 anti-cKIT antibody drug conjugates effectively ablate hematopoietic stem cells while minimizing mast cell degranulation, even when cross-linked or multimerized, thus reducing adverse reactions and improving transplantation outcomes.
Implementation Method 1
an antibody or antibody fragment (e.g., Fab or Fab') that specifically binds to human cKIT is linked to a drug moiety (e.g., a cytotoxic agent)
Data Source
AI summary
The present invention provides antibody drug conjugates, wherein an antibody or antibody fragment that specifically binds to human cKIT is linked to a drug moiety, optionally through a linker. The present invention further provides pharmaceutical compositions comprising the antibody drug conjugates; and methods of making and using such pharmaceutical compositions for ablating hematopoetic stem cells in a patient in need thereof.