Covalent PD-1×LAG-3 Diabodies for Dual Checkpoint Blockade
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Solution Overview
Problem
Existing immune therapies are hampered by immune suppressive mechanisms in the tumor microenvironment, such as the expression of PD-1 and LAG-3, which dominantly attenuate T-cell responses against cancer cells, necessitating improved compositions to vigorously direct the immune system against cancer and pathogen-infected cells.
Innovation Solution
Development of PD-1×LAG-3 bi-specific, tetra-valent diabodies that covalently bind to PD-1 and LAG-3 cell-surface molecules on exhausted and tolerant tumor-infiltrating lymphocytes, blocking their inhibitory signals and promoting continued immune activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional immune therapies are used, then treatment is provided, but immune suppressive mechanisms (PD-1 and LAG-3 expression) attenuate T-cell responses
Solution Approach 1:
The patent combines two separate immune checkpoint targets (PD-1 and LAG-3) into a single bispecific diabody molecule. This merged approach allows simultaneous blockade of both suppressive pathways, overcoming the limitation of conventional monospecific therapies that could only address one checkpoint at a time.
Solution Approach 2:
The diabody is designed with dual functionality to bind both PD-1 and LAG-3 receptors. This multi-functional molecule can simultaneously engage multiple immune checkpoint targets, providing broader coverage against immune suppression compared to conventional single-target therapies.
2Productivity
If T-cell responses are enhanced to overcome immune suppression, then immune activation is improved, but immune exhaustion and tolerance may dominate
Solution Approach 1:
The diabody preemptively blocks both PD-1 and LAG-3 inhibitory signals before they can suppress T-cell activation. By preventing the establishment of immune exhaustion and tolerance early in the immune response, the therapy maintains sustained T-cell productivity throughout the treatment course.
3Device complexity
If monospecific antibodies are used to block single checkpoints, then simplicity is maintained, but immune suppression is insufficiently countered
Solution Approach 1:
The patent merges two checkpoint-blocking functions into a single diabody molecule, achieving dual blockade without requiring separate antibody administrations. This reduces therapeutic complexity while enhancing the reliability of immune suppression counteraction.
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 diabodies effectively block PD-1 and LAG-3-mediated immune inhibition, enhancing T-cell proliferation and cytokine production, thereby improving the immune response against cancer and pathogen-associated diseases.
Implementation Method 1
The first and second polypeptide chains are covalently bonded to one another, the second and third polypeptide chains are covalently bonded to one another, and the third and fourth polypeptide chains are covalently bonded to one another
Data Source
AI summary
The present invention is directed to bi-specific diabodies that comprise two or more polypeptide chains and which possess at least one Epitope-Binding Site that is immunospecific for an epitope of PD-1 and at least one Epitope-Binding Site that is immunospecific for an epitope of LAG-3 (i.e., a “PD-1×LAG-3 bi-specific diabody”). More preferably, the present invention is directed to bi-specific diabodies that comprise four polypeptide chains and which possess two Epitope-Binding Sites that are immunospecific for one (or two) epitope(s) of PD-1 and two Epitope-Binding Site that are immunospecific for one (or two) epitope(s) of LAG-3 (i.e., a “PD-1×LAG-3 bi-specific, tetra-valent diabody”). The present invention also is directed to such diabodies that additionally comprise an immunoglobulin Fc Domain (“bi-specific Fc diabodies and bi-specific, tetra-valent, Fc diabodies”). The diabodies of the present invention are capable of simultaneously binding to PD-1 and to LAG-3, particularly as such molecules are arrayed on the surfaces of human cells. The invention is directed to pharmaceutical compositions that contain such diabodies, and to methods involving the use of such diabodies in the treatment of cancer and other diseases and conditions.