Co-Stimulation through 4-1BB/CD137 Improves the Expansion and Function of CD8+ Melanoma Tumor-Infiltrating Lymphocytes for Adoptive T-Cell Therapy

Abstract

Adoptive T-cell therapy (ACT) using tumor-infiltrating lymphocytes (TIL) can induce tumor regression in up to 50% or more of patients with unresectable metastatic melanoma. However, current methods to expand melanoma TIL, especially the “rapid expansion protocol” (REP) were not designed to enhance the generation of optimal effector-memory CD8+ T cells for infusion. One approach to this problem is to manipulate specific co-stimulatory signaling pathways to enhance CD8+ effector-memory T-cell expansion. In this study, we determined the effects of activating the TNF-R family member 4-1BB/CD137, specifically induced in activated CD8+ T cells, on the yield, phenotype, and functional activity of expanded CD8+ T cells during the REP. We found that CD8+ TIL up-regulate 4-1BB expression early during the REP after initial TCR stimulation, but neither the PBMC feeder cells in the REP or the activated TIL expressed 4-1BB ligand. However, addition of an exogenous agonistic anti-4-1BB IgG4 (BMS 663513) to the REP significantly enhanced the frequency and total yield of CD8+ T cells as well as their maintenance of CD28 and increased their anti-tumor CTL activity. Gene expression analysis found an increase in bcl-2 and survivin expression induced by 4-1BB that was associated with an enhanced survival capability of CD8+ post-REP TIL when re-cultured in the absence or presence of cytokines. Our findings suggest that adding an agonistic anti-4-1BB antibody during the time of TIL REP initiation produces a CD8+ T cell population capable of improved effector function and survival. This may greatly improve TIL persistence and anti-tumor activity in vivo after adoptive transfer into patients.

Focusing and sustaining the antitumor CTL effector killer response by agonist anti-CD137 mAb

“…First, CD137 expression can be used for immunomagnetic selection of tumor reactive TILs (38), and subsequent culture of T cells in the presence of CD137 renders more efficacious phenotypic features (39,40). Second, the effector performance (11), survival (10), and memory differentiation (41) can be enhanced by coadministration of the agonist antibody in vivo.…”

Results from an Integrated Safety Analysis of Urelumab, an Agonist Anti-CD137 Monoclonal Antibody

“…PF-05082566 (Pfizer) is a fully human IgG2 mAb (13). In preclinical studies, urelumab enhanced IFNg production, T-cell survival, and the cytolytic activity of antigen-specific T cells (11,12,14), as expected for an antibody with costimulatory activity. Urelumab entered clinical development in 2005 and was evaluated as a monotherapy in two studies, CA186-001 (NCT00309023) and CA186-006 (NCT00612664).…”

Antigen-Specific Antitumor Responses Induced by OX40 Agonist Are Enhanced by the IDO Inhibitor Indoximod

“…To generate strong and long-lasting anti-cancer immune response upon antigen recognition, an engagement of secondary costimulatory receptors is often employed in combinational immune therapeutic studies (4)(5)(6)(7)(8).…”