FLT3-Binding CAR T-Cells for Targeted AML Therapy
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Solution Overview
Problem
Current therapies for acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) face challenges such as high toxicity and relapse rates due to conventional chemotherapies, and CAR T-cell therapies against AML are still in the early stages with concerns about toxicity and target antigen specificity.
Innovation Solution
Development of a chimeric antigen receptor (CAR) T-cell therapy using a FLCAR construct that includes an FLT3-binding extracellular domain, a CD28 transmembrane domain, and a CD3-zeta intracellular signaling domain to selectively target and kill FLT3-expressing leukemia cells, reducing toxicity and improving treatment efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chemotherapeutic agents are used to treat leukemia, then cancer cells can be killed, but numerous side effects and high toxicity occur leading to short-term and long-term morbidity
Solution Approach 1:
The patent uses CAR T-cells as intermediary agents that specifically recognize and bind to FLT3-expressing leukemia cells through the chimeric antigen receptor. This mediator approach allows targeted delivery of cytotoxic activity only to cancer cells expressing the target antigen, sparing healthy tissues from chemotherapy-induced damage and reducing systemic toxicity while maintaining anti-tumor efficacy
2Reliability
If CAR T-cell therapy uses monoclonal antibody-derived antigen receptors, then T-cells can be redirected to target cancer cells, but off-target toxicity and hypersensitivity reactions occur
Solution Approach 1:
The patent applies local quality by designing the CAR extracellular domain to specifically recognize FLT3, a receptor predominantly expressed on AML cells. This localized specificity ensures that the cytotoxic effect is concentrated on the target antigen-positive cells while minimizing off-target effects on healthy tissues that do not express FLT3
Solution Approach 2:
The patent optimizes the binding affinity parameter of the CAR-antigen interaction. By engineering the extracellular domain with moderate affinity for FLT3, the system achieves sufficient target recognition and T-cell activation while avoiding overly strong binding that could cause off-target effects or excessive activation of healthy cells
3Reliability
If CAR T-cell therapy uses high antigen-antibody affinity, then T-cell redirection to cancer cells is enhanced, but the risk of toxicity and immunogenic clearance increases
Solution Approach 1:
The patent systematically optimizes the binding affinity parameter of the CAR extracellular domain to FLT3. By adjusting this parameter to achieve moderate rather than high affinity, the system maintains effective T-cell redirection to cancer cells while reducing the risk of off-target toxicity and immunogenic clearance of the CAR T-cells
4Reliability
If intensive multi-agent chemotherapy is administered in multiple cycles, then remission can be achieved, but relapse occurs in 50-70% of AML patients within five years
Solution Approach 1:
The patent employs CAR T-cells with self-renewal and persistence capabilities. These genetically modified T-cells can self-maintain and persist in the patient's body for extended periods, providing long-term surveillance and elimination of residual leukemia cells, thereby preventing relapse without requiring repeated intensive chemotherapy cycles
Solution Approach 2:
The patent creates a continuous anti-tumor immune response through persistent CAR T-cell populations that continuously patrol and eliminate FLT3-expressing leukemia cells. This ongoing therapeutic action replaces the discontinuous multi-cycle chemotherapy approach, providing sustained disease control and reducing relapse risk
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 FLCAR T-cells demonstrate potent cytotoxicity against FLT3-expressing AML cells in vitro and in vivo, significantly prolonging the survival of mice engrafted with leukemia cells, indicating a promising approach for AML treatment with reduced side effects.
Implementation Method 1
The extracellular domain of CAR, also called the antigen binding domain, is responsible for tumor specificity and overall affinity
Implementation Method 2
The intracellular signaling domain is generally made up of proteins like the CD3 zeta chain that are responsible for downstream signaling from the CAR
Implementation Method 3
The fundamental idea behind a CAR T-cell is to design a T-cell receptor that has affinity for a specific tumor associated antigen (TAA) thereby enabling the T-cell to target and destroy the particular cancer cell
Data Source
AI summary
A chimeric antigen receptor (CAR) comprising (1) an extracellular portion of human Fms-related tyrosine kinase 3 ligand (FLT3L) that binds to Fms-related tyrosine kinase 3 (FLT3), (2) a transmembrane domain, (3) a costimulatory signaling domain, and (4) an intracellular signaling domain. A nucleic acid sequence encoding the CAR. A vector and cell comprising the nucleic acid sequence encoding the CAR. A cell expressing the CAR. A composition of cells expressing the CAR. A method of administering the composition of cells expressing the CAR to a subject for stimulating in the subject an immune response against cells which express FLT3.