Lifileucel, an Autologous Tumor-infiltrating Lymphocyte Monotherapy, in Patients with Advanced Non-small Cell Lung Cancer Resistant to Immune Checkpoint Inhibitors.

In this phase 2 multicenter study, we evaluated the efficacy and safety of lifileucel (LN-145), an autologous tumor-infiltrating lymphocyte cell therapy, in patients with metastatic non-small cell lung cancer (mNSCLC) who had received prior immunotherapy and progressed on their most recent therapy. The median number of prior systemic therapies was 2 (range, 1-6). Lifileucel was successfully manufactured using tumor tissue from different anatomic sites, predominantly lung. The objective response rate was 21.4% (6/28). Responses occurred in tumors with profiles typically resistant to immunotherapy, such as PD-L1-negative, low tumor mutational burden, and STK11 mutation. Two responses were ongoing at the time of data cutoff, including one complete metabolic response in a PD-L1-negative tumor. Adverse events were generally as expected and manageable. Two patients died of treatment-emergent adverse events: cardiac failure and multiple organ failure. Lifileucel is a potential treatment option for patients with mNSCLC refractory to prior therapy.

Adjuvant Screen Identifies Synthetic DNA-Encoding Flt3L and CD80 Immunotherapeutics as Candidates for Enhancing Anti-tumor T Cell Responses.

Overcoming tolerance to tumor-associated antigens remains a hurdle for cancer vaccine-based immunotherapy. A strategy to enhance the anti-tumor immune response is the inclusion of adjuvants to cancer vaccine protocols. In this report, we generated and systematically screened over twenty gene-based molecular adjuvants composed of cytokines, chemokines, and T cell co-stimulators for the ability to increase anti-tumor antigen T cell immunity. We identified several robust adjuvants whose addition to vaccine formulations resulted in enhanced T cell responses targeting the cancer antigens STEAP1 and TERT. We further characterized direct T cell stimulation through CD80-Fc and indirect T cell targeting via the dendritic cell activator Flt3L-Fc. Mechanistically, intramuscular delivery of Flt3L-Fc into mice was associated with a significant increase in infiltration of dendritic cells at the site of administration and trafficking of activated dendritic cells to the draining lymph node. Gene expression analysis of the muscle tissue confirmed a significant up-regulation in genes associated with dendritic cell signaling. Addition of CD80-Fc to STEAP1 vaccine formulation mimicked the engagement provided by DCs and increased T cell responses to STEAP1 by 8-fold, significantly increasing the frequency of antigen-specific cells expressing IFNγ, TNFα, and CD107a for both CD8+ and CD4+ T cells. CD80-Fc enhanced T cell responses to multiple tumor-associated antigens including Survivin and HPV, indicating its potential as a universal adjuvant for cancer vaccines. Together, the results of our study highlight the adjuvanting effect of T cell engagement either directly, CD80-Fc, or indirectly, Flt3L-Fc, for cancer vaccines.

Colony-stimulating factor (CSF) 1 receptor blockade reduces inflammation in human and murine models of rheumatoid arthritis.

BACKGROUND: CSF-1 or IL-34 stimulation of CSF1R promotes macrophage differentiation, activation and osteoclastogenesis, and pharmacological inhibition of CSF1R is beneficial in animal models of arthritis. The objective of this study was to determine the relative contributions of CSF-1 and IL-34 signaling to CSF1R in RA. METHODS: CSF-1 and IL-34 were detected by immunohistochemical and digital image analysis in synovial tissue from 15 biological-naïve rheumatoid arthritis (RA) , 15 psoriatic arthritis (PsA) and 7 osteoarthritis (OA) patients . Gene expression in CSF-1- and IL-34-differentiated human macrophages was assessed by FACS analysis and quantitative PCR. RA synovial explants were incubated with CSF-1, IL-34, control antibody (Ab), or neutralizing/blocking Abs targeting CSF-1, IL-34, or CSF1R. The effect of a CSF1R-blocking Ab was examined in murine collagen-induced arthritis (CIA). RESULTS: CSF-1 (also known as M-CSF) and IL-34 expression was similar in RA and PsA synovial tissue, but lower in controls (P < 0.05). CSF-1 expression was observed in the synovial sublining, and IL-34 in the sublining and the intimal lining layer. CSF-1 and IL-34 differentially regulated the expression of 17 of 336 inflammation-associated genes in macrophages, including chemokines, extra-cellular matrix components, and matrix metalloproteinases. Exogenous CSF-1 or IL-34, or their independent neutralization, had no effect on RA synovial explant IL-6 production. Anti-CSF1R Ab significantly reduced IL-6 and other inflammatory mediator production in RA synovial explants, and paw swelling and joint destruction in CIA. CONCLUSIONS: Simultaneous inhibition of CSF1R interactions with both CSF-1 and IL-34 suppresses inflammatory activation of RA synovial tissue and pathology in CIA, suggesting a novel therapeutic strategy for RA.

Targeting IL-34 in chronic inflammation.

A second ligand for colony-stimulating factor-1 receptor (CSF-1R) with distinct biologic activities had long been implicated but not appreciated until the recent discovery of interleukin (IL)-34. IL-34 and CSF-1 signal through this common receptor to mediate the biology of mononuclear phagocytic cells. Aberrant macrophage activation by CSF-1 and/or IL-34 is associated with numerous diseases, and clinical therapies targeting this pathway are being tested. Although IL-34 and CSF-1 have distinct activities under physiologic conditions, they appear functionally redundant in various disease states. Thus, blocking the activity of both might be necessary for maximal efficacy.

Antigen-specific regulatory T cells--ex vivo expansion and therapeutic potential.

CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) are critical for the regulation of tolerance and have shown enormous potential in suppressing pathological immune responses in autoimmune disease, transplantation, and graft-versus-host disease (GVHD). Recent data indicate that suppression of organ-specific autoimmunity is critically dependent on the antigen specificity of the Treg. An emerging model of Treg action is that organ-specific Treg acquire suppressive activity through activation by dendritic cells expressing organ-derived antigens. Thus, efficacy of Treg-based therapy should be increased by using organ-specific Treg rather than polyclonal Treg. This necessitates the ability to identify relevant antigens and to expand rare antigen-specific Treg from diverse polyclonal populations. Here, we consider the importance of antigen specificity in Treg function and discuss recent advances for the expansion of antigen-specific Treg and the therapeutic potential of Treg in controlling autoimmunity and GVHD.

In vitro-expanded antigen-specific regulatory T cells suppress autoimmune diabetes.

The low number of CD4+ CD25+ regulatory T cells (Tregs), their anergic phenotype, and diverse antigen specificity present major challenges to harnessing this potent tolerogenic population to treat autoimmunity and transplant rejection. In this study, we describe a robust method to expand antigen-specific Tregs from autoimmune-prone nonobese diabetic mice. Purified CD4+ CD25+ Tregs were expanded up to 200-fold in less than 2 wk in vitro using a combination of anti-CD3, anti-CD28, and interleukin 2. The expanded Tregs express a classical cell surface phenotype and function both in vitro and in vivo to suppress effector T cell functions. Most significantly, small numbers of antigen-specific Tregs can reverse diabetes after disease onset, suggesting a novel approach to cellular immunotherapy for autoimmunity.

Directed evolution of a single-chain class II MHC product by yeast display.

Many autoimmune diseases have been linked to the class II region of the major histocompatibility complex (MHC). The linkage is thought to be a result of autoreactive T cells that recognize self-peptides bound to a product of this locus. For example, T cells from non-obese diabetic mice recognize specific 'diabetogenic' peptides bound to a class II MHC allele called I-A(g7). The I-A(g7) molecule is noted for being unstable and difficult to work with, especially in soluble form. In this work, yeast surface display combined with fluorescence-activated cell sorting was used as a means of directed evolution to engineer stabilized variants of a single-chain form of I-A(g7). A library containing mutations at two residues (positions 56 and 57 of the I-A(g7) beta-chain) that are important in the class II disease associations yielded stabilized mutants with preferences for a glutamic acid at residue 56 and a leucine at residue 57. Random mutation of I-A(g7) followed by selection with an anti-I-A(g7) antibody also yielded stabilized variants with mutations in other residues. The methods described here allow the discovery of novel MHC complexes that could facilitate structural studies and provide new opportunities in the development of diagnostics or antagonists of class II MHC-associated diseases.