Start Your Search
O08 - Preclinical Therapeutic Models I (ID 92)
- Event: WCLC 2013
- Type: Oral Abstract Session
- Track: Biology
- Presentations: 1
- Moderators:C. Mascaux, R. Natale
- Coordinates: 10/28/2013, 16:15 - 17:45, Bayside Auditorium A, Level 1
O08.02 - Critical Role of CD28 Costimulation in Tumor-Targeted T-cell Therapy Clinical Trial for Pleural Malignancies (ID 2995)
16:15 - 17:45 | Author(s): E. Servais
Successful translation of adoptive T-cell therapy for solid cancers is predicated on the ability to generate a potent antitumor immune response and establish T-cell persistence. Thoracic malignancies typically lack expression of costimulatory ligands but do express negative regulators of T- cell function—factors that may impede T-cell therapy. We hypothesized that cancer antigen–targeted T cells engineered with activating CD28 costimulatory signaling would eradicate tumor and establish long-term functional persistence.
Mesothelin-specific chimeric antigen receptors (CARs) were engineered without (Mz) or with (M28z) a CD28 costimulatory domain. CAR-transduced human T cells were evaluated in vitro for cytotoxicity (Cr-release assay), cytokine release (Luminex cytokine-release assay), and proliferation (cell-counting assay). In vivo assessment included monitoring of tumor progression by bioluminescence imaging (BLI), flow cytometric analysis of splenic/peripheral blood T-cell phenotypes, and Kaplan-Meier analysis of median survival, in NOD-scid IL-2Rγ-null mice bearing orthotopically implanted mesothelin-expressing mesothelioma cells (MSTO-211H: CD80/86-, TGF-β+, PD-L1+) and treated with human T cells transduced to express either Mz, M28z, or a control vector.
In vitro, M28z CAR–transduced T cells exhibited equivalent cytotoxicity but enhanced Th1 cytokine secretion and antigen-specific proliferation, compared with Mz transduced T cells. In vivo, mice treated with a single low dose of M28z CAR–transduced T cells achieved tumor eradication and prolonged survival (median survival not reached; p=0.01), compared with mice treated with an equal dose of Mz-transduced (median survival, 63 days; tumor eradication in 20% of mice) or control CAR–transduced (median survival, 36 days) T cells (Figure 1A, 1B). Furthermore, CD28 costimulation enhanced CD62L[-]CD45RA[-] effector memory T-cell persistence (Figure 1C), leading to a robust T-cell proliferative response and superior control of tumor burden on tumor rechallenge 87 days after T-cell administration (Figure 1D, 1E). Figure 1
CD28 costimulation plays an important role in achieving long-term antitumor efficacy and functional persistence in mesothelin-targeted T-cell therapy. These data provide the scientific rationale for our upcoming clinical trial for pleural malignancies.
Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.