Stem Cell Engraftment Conditioning With Anti-CD117 and 5-Azacytidine
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Solution Overview
Problem
The toxicity of conventional conditioning regimens for hematopoietic stem cell transplantation (HCT) poses a significant obstacle, limiting its widespread use due to high morbidity and mortality, and existing anti-CD117 monoclonal antibodies show reduced efficacy in engraftment of stem cells in immunocompetent mice.
Innovation Solution
A combined non-myeloablative conditioning regimen using an anti-CD117 agent, such as a humanized monoclonal antibody, and a hypomethylating agent like 5-azacytidine, followed by a wash-out period, facilitates the engraftment of exogenous stem cells without toxic depletion, allowing for long-term multilineage engraftment and immune tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional myeloablative conditioning regimens (alkylating agents or radiation) are used to deplete endogenous stem cells, then stem cell engraftment is achieved, but toxicity and morbidity increase significantly
Solution Approach 1:
The patent changes the mechanism of stem cell depletion from myeloablative (DNA-damaging) to non-myeloablative (CD117-targeted). By using anti-CD117 monoclonal antibodies instead of alkylating agents or radiation, the patent achieves selective depletion of hematopoietic stem cells through receptor targeting, thereby maintaining engraftment capability while dramatically reducing toxicity to other tissues
Solution Approach 2:
The patent replaces the mechanical/physical mechanism of DNA damage (radiation or alkylating agents) with a biological mechanism of receptor-mediated targeting. The anti-CD117 antibody binds to the c-Kit receptor on stem cells, triggering selective depletion through biological interaction rather than physical destruction, thus achieving the same functional outcome with reduced harm
2Object-affected harmful factors
If anti-CD117 monoclonal antibody is used to deplete host HSC, then targeted depletion is achieved with little off-target toxicity, but engraftment resistance occurs in wildtype immunocompetent mice
Solution Approach 1:
The patent combines anti-CD117 monoclonal antibody with low-dose irradiation to create a synergistic conditioning regimen. The antibody provides targeted stem cell depletion with minimal off-target effects, while the low-dose irradiation enhances the depletion effect and creates favorable conditions for engraftment. This combination resolves the contradiction by achieving both selective depletion and reliable engraftment without the toxicity of conventional regimens
Solution Approach 2:
The patent modifies the dosage parameter of irradiation to low-dose levels, transforming it from a myeloablative agent to a mild conditioning agent. This parameter change allows the irradiation to enhance stem cell depletion and engraftment without causing excessive toxicity, working synergistically with the anti-CD117 antibody to overcome engraftment resistance
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
This approach enhances the effectiveness of stem cell engraftment, reduces toxicity, and enables robust reconstitution of immunocompetence, even in immunocompetent recipients, without myeloablative conditioning or graft-vs-host disease, and supports the treatment of various hematologic disorders and malignancies.
Implementation Method 1
treating the recipient with a pre-transplantation non-myeloablative conditioning regimen comprising an effective dose of an agent specific for CD117 (referred to as an anti-CD117 agent)
Implementation Method 2
an effective dose of a hypomethylating agent, e.g. a cytosine analog
Data Source
AI summary
The present invention provides a clinically applicable method of bone marrow conditioning for stem cell transplantation or therapeutic treatment of hematologic malignancies.