Mutated CD28 CARs for T Cell Exhaustion

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Solution Overview

Problem

Second-generation CAR T cells experience low-level tonic signaling and exhaustion due to CD28 co-stimulation, leading to relapses and toxicities, indicating a need to refine CAR T cell function by modulating CD28 co-stimulation.

Innovation Solution

Development of chimeric antigen receptors (CARs) with a mutated form of the CD28 co-stimulatory domain, specifically modifying subdomains YMNM, PRRP, and PYAP to reduce CAR-T cell exhaustion, combined with modifications in CD3zeta and/or 41BB domains, to enhance CAR-T cell function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If second-generation CARs include co-stimulatory domains such as CD28 or 41BB, then tumor killing efficacy is improved, but T cell persistence deteriorates and excessive T cell activation occurs leading to toxicities

Engineering Contradiction:

Improvetumor killing efficacyVSAvoidT cell persistence

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The CD28 co-stimulatory domain is segmented into three functional subdomains (YMNM, PRRP, PYAP), and specific subdomains are selectively mutated or removed to eliminate harmful tonic signaling while preserving essential co-stimulatory functions for tumor killing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Amino acid substitutions are introduced into the CD28 domain (e.g., Y176A, M177A, N178A in the YMNM subdomain) to alter signaling parameters and eliminate constitutive activation while maintaining inducible co-stimulation upon antigen recognition

Inventive Principle:

Principle #35Parameter changes

2Power

If CD28 co-stimulatory domain is included in CAR, then cytokine production is enhanced, but low-level tonic signaling occurs leading to exhaustion phenotype

Engineering Contradiction:

Improvecytokine productionVSAvoidexhaustion phenotype

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The harmful tonic signaling property of the CD28 domain is converted into a beneficial inducible co-stimulatory signal by mutating residues that cause constitutive activation, thereby eliminating exhaustion while preserving enhanced cytokine production capability upon target engagement

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12065474B2Chimeric antigen receptors with mutated CD28 costimulatory domains

Publication Date: 2024.08.20 H LEE MOFFITT CANCER CENTER & RESEARCH INSTITUTE INC

AI summary

Disclosed herein are chimeric antigen receptor (CAR) polypeptides, which can be used with adoptive cell transfer to target and kill cancers, that comprise a co-stimulatory signaling region having a mutated form of a cytoplasmic domain of CD28 that enhances CAR-T cell function, e.g. by reducing CAR-T cell exhaustion. Also disclosed are immune effector cells, such as T cells or Natural Killer (NK) cells, that are engineered to express these CARs. Therefore, also disclosed are methods of providing an anti-tumor immunity in a subject with a tumor associated antigen-expressing cancer that involves adoptive transfer of the disclosed immune effector cells engineered to express the disclosed CARs.