# CD28-KITv CAR T cells with PD-1 dominant negative receptor

> **NIH NIH UG3** · SLOAN-KETTERING INST CAN RESEARCH · 2024 · $1,491,519

## Abstract

PROJECT ABSTRACT
The success of chimeric antigen receptor (CAR) T-cell therapy in solid tumors requires antigen targets with no
on-target, off-tumor toxicity, effective tumor infiltration, cytotoxicity and proliferation in an immunosuppressive
environment, and revival of antigen stress-induced exhausted CAR T cells. We translated CD28-costimulated
CARs (M28z) that target mesothelin (MSLN), a cancer-associated antigen that we have documented
expression in majority of solid tumors; 64 patients have been treated to date, with no on-target, off-tumor
toxicity. Having demonstrated that regionally administered CAR T cells avoid pulmonary sequestration and
benefit from early antigen-activated CD4 helper CAR T-cell function, we delivered CAR T cells intrapleurally in
patients with malignant pleural mesothelioma (MPM), promoting tumor infiltration. To address T-cell
exhaustion, we either treated patients with anti-PD1 agent after CAR T cells or employed tumor-specific
checkpoint blockade by CAR T-cell intrinsic PD1 dominant negative receptor (PD1DNR); 34 patients have
been treated to date, with no CAR- or PD1DNR-related toxicities and with responses by imaging, and
increased survival. To promote IFNγ-mediated cytotoxicity shown to be essential for solid tumor killing, we
exploited a c-KIT mutation, D816V (KITv), as a costimulatory domain. KITv CAR T cells show antigen-
activation induced IFNγ signaling, enhanced cytotoxicity, and when added as signal 3 to CD28 (signal 2),
provide a synergistic function, resist TGFβ-mediated suppression, and prolong functional persistence.
Clinically available kinase inhibitors provide an on/off, tunable safety switch for KITv CAR T cells. To effectively
deliver these next-generation CAR T cells to solid tumors, we developed a translational strategy of non-
ablative, tumor-targeted radiation therapy (RT) to generate a chemokine gradient that facilitates systemically
administered CAR T-cell chemotaxis, tumor infiltration, proliferation, and persistence. Herein, we seek to
translate the M28zKITv-PD1DNR CAR T cells to address key limitations in solid tumor cell therapy. In UG3
phase, we will explore the hypothesis that PD1DNR checkpoint blockade extends beyond tumor cells and
counteracts PDL1-expressing M2 macrophages with immune suppressor function (Aim 1). We will define
optimal regimen of non-ablative, tumor-targeted RT to promote tumor infiltration of systemically administered
CAR T cells, achieving efficacy similar to that with regional delivery. In Aim 3, we will submit an IND
application, a process with which we are familiar and have track record of success. In UH3 phase, we will
conduct a phase I study to investigate the safety, functional activity and efficacy, and markers of response in
patients with MPM. The significance of our approach lies in its effective combination of solid tumor-specific–
scFv that is on-target and safe (MSLN), costimulatory domains (CD28, KITv), checkpoint blockade (PD1DNR),
and a strategy o...

## Key facts

- **NIH application ID:** 10876785
- **Project number:** 1UG3CA290241-01
- **Recipient organization:** SLOAN-KETTERING INST CAN RESEARCH
- **Principal Investigator:** Prasad S. Adusumilli
- **Activity code:** UG3 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $1,491,519
- **Award type:** 1
- **Project period:** 2024-03-01 → 2026-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10876785

## Citation

> US National Institutes of Health, RePORTER application 10876785, CD28-KITv CAR T cells with PD-1 dominant negative receptor (1UG3CA290241-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10876785. Licensed CC0.

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