Selective HSC Depletion Conditioning for HLA-Mismatched Transplants
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Solution Overview
Problem
Current methods for conditioning patients for allogeneic transplantation, such as organ or tissue transplants, are highly toxic and lead to life-threatening side effects, and there is a need for methods that can condition patients to tolerate HLA-mismatched donors to increase access to transplants and reduce graft rejection and GVHD.
Innovation Solution
A method involving the use of an HSC-depleting composition, such as antibodies or antibody fragments with specific binding affinity to HSC surface proteins, to deplete hematopoietic stem cells, followed by administration of allogeneic cells and optional immunosuppressive agents to condition patients for transplantation from HLA-mismatched donors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If myeloablation by radiation, chemotherapy and immunosuppressive drugs is used to condition patients for transplantation, then graft acceptance is achieved, but severe toxicity and life-threatening side effects occur
Solution Approach 1:
The patent segments the conditioning process into two distinct components: (1) selective depletion of hematopoietic stem cells using anti-CD34 antibodies, and (2) suppression of T-cell mediated rejection. This segmentation allows each component to be optimized independently, reducing overall toxicity while maintaining graft acceptance efficacy.
Solution Approach 2:
The patent extracts and targets specifically the hematopoietic stem cell compartment for depletion, rather than causing pan-myeloablation. By using anti-CD34 antibodies that specifically bind to CD34+ stem cells, the treatment removes only the necessary target cells while sparing other bone marrow elements, thereby reducing toxicity.
2Object-affected harmful factors
If nonmyeloablative conditioning with selective HSC depletion is used, then toxicity is reduced, but graft rejection risk increases
Solution Approach 1:
The patent merges two therapeutic approaches: (1) selective HSC depletion via anti-CD34 antibodies to reduce immunosuppression needs, and (2) T-cell targeted therapy (anti-CD3 or anti-CD154 antibodies) to prevent graft rejection. This combination allows nonmyeloablative conditioning to achieve both reduced toxicity and maintained graft acceptance.
Solution Approach 2:
The patent introduces T-cell depletion or inhibition as an intermediary mechanism to bridge the gap between reduced myeloablation and graft acceptance. By targeting T-cells (the primary mediators of rejection), the patent compensates for the reduced intensity of conditioning while maintaining effective graft acceptance.
3Reliability
If HLA-matched donors are required for transplantation, then graft acceptance is improved, but donor pool availability decreases
Solution Approach 1:
The patent changes the immunological parameters of the recipient through selective HSC depletion and T-cell targeted therapy. This parameter change allows the recipient's immune system to tolerate HLA-mismatched grafts that would otherwise be rejected, thereby expanding the usable donor pool beyond strictly HLA-matched donors.
4Object-affected harmful factors
If T-cell depletion is used to prevent GVHD, then GVHD incidence is reduced, but graft failure and relapse risk increase
Solution Approach 1:
The patent performs preliminary depletion of the recipient's HSCs before transplant, creating space and reducing immune resistance to the donor graft. This preliminary action facilitates better engraftment of donor cells, compensating for any T-cell depletion in the graft and maintaining graft-versus-leukemia effects.
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 method enhances tolerance to allogeneic transplants, reducing graft rejection and GVHD, and increases the pool of acceptable donors without genetic manipulation of donor cells.
Implementation Method 1
antibodies or antibody fragments with specific binding affinity to HSC surface proteins
Data Source
AI summary
Provided are methods and compositions conditioning a patient for an allogeneic transplantation, wherein the patient's hematopoietic stem cells (HSCs) are depleted with an HSC-depleting composition and the patient is then administered allogeneic cells selected from bone marrow cells, umbilical cord blood cells, hematopoietic stem and progenitor cells (HSPCs), peripheral blood CD34+ cells, and peripheral blood CD34+ and CD90+ cells; optionally the patient is also administered a medicament selected from the group consisting of a T-cell depleting or inhibiting antibody or antibody fragment, NK-cell depleting or inhibiting antibody or antibody fragment, immunosuppressive drug, and any combination thereof. The HSC-depleting composition comprises a compound selected from the group consisting of: an antibody or antibody fragment with specific binding affinity to a protein displayed at the HSC surface, a conjugate comprising an HSC-recognition molecule and a toxin, and any combination thereof.