Five-Year Outcomes With Pembrolizumab Versus Chemotherapy as First-Line Therapy in Patients With Non-Small-Cell Lung Cancer and Programmed Death Ligand-1 Tumor Proportion Score ≥ 1% in the KEYNOTE-042 Study.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.We report 5-year results from the phase III KEYNOTE-042 study (ClinicalTrials.gov identifier: NCT02220894). Eligible patients with locally advanced/metastatic non-small-cell lung cancer (NSCLC) without EGFR/ALK alterations and with programmed death ligand-1 (PD-L1) tumor proportion score (TPS) ≥ 1% received pembrolizumab 200 mg once every 3 weeks for 35 cycles or chemotherapy (carboplatin + paclitaxel or pemetrexed) for 4-6 cycles with optional maintenance pemetrexed. Primary end points were overall survival (OS) in PD-L1 TPS ≥ 50%, ≥ 20%, and ≥ 1% groups. Patients who completed 35 cycles of pembrolizumab with ≥ stable disease could begin second-course pembrolizumab upon progression. One thousand two hundred seventy-four patients were randomly assigned (pembrolizumab, n = 637; chemotherapy, n = 637). Median follow-up time was 61.1 (range, 50.0-76.3) months. OS outcomes favored pembrolizumab (v chemotherapy) regardless of PD-L1 TPS (hazard ratio [95% CI] for TPS ≥ 50%, 0.68 [0.57 to 0.81]; TPS ≥ 20%, 0.75 [0.64 to 0.87]; TPS ≥ 1%, 0.79 [0.70 to 0.89]), with estimated 5-year OS rates with pembrolizumab of 21.9%, 19.4%, and 16.6%, respectively. No new toxicities were identified. Objective response rate was 84.3% among 102 patients who completed 35 cycles of pembrolizumab and 15.2% among 33 patients who received second-course pembrolizumab. First-line pembrolizumab monotherapy continued to show durable clinical benefit versus chemotherapy after 5 years of follow-up in PD-L1-positive, locally advanced/metastatic NSCLC without EGFR/ALK alterations and remains a standard of care.

Exogenous CLIP localizes into endocytic compartment of cells upon internalization: implications for antigen presentation by MHC class II molecules.

We have previously shown that exogenous CLIP (class II associated invariant chain peptide) downregulated MHC class II expression on antigen presenting cells (APC) and modulated T cell mediated immune responses. The present study was undertaken to investigate the mechanism of uptake of exogenously added CLIP peptide by APC. We found that exogenous CLIP is rapidly internalized by APC and it co-localize with MHC class II in intracellular compartments including early-, late-endosomes and lysosomes. We suggest that exogenous CLIP acts as an in vivo regulator of immune response by internalization and passage through the intracellular compartments where it interferes in peptide loading and recycling of MHC class II molecules to the APC surface. Therefore, exogenous CLIP regulates immune responses by modulation of antigen presentation by the APC.

Role of TGF-ß in Self-Peptide Regulation of Autoimmunity.

Transforming growth factor (TGF)-ß has been implicated in regulation of the immune system, including autoimmunity. We have found that TGF-ß is readily produced by T cells following immunization with self-peptide epitopes that downregulate autoimmune responses in type 1 diabetes (T1D) prone nonobese diabetic (NOD) mice. These include multiple peptide epitopes derived from the islet ß-cell antigens GAD65 (GAD65 p202-221, GAD65 p217-236), GAD67 (GAD67 p210-229, GAD67 p225-244), IGRP (IGRP p123-145, IGRP p195-214) and insulin B-chain (Ins. B:9-23) that protected NOD mice from T1D. Immunization of NOD mice with the self-MHC class II I-Ag7 ß-chain-derived peptide, I-Aßg7 p54-76 also induced large amounts of TGF-ß and also protected these mice from diabetes development. These results indicate that peptides derived from disease related self-antigens and MHC class II molecules primarily induce TGF-ß producing regulatory Th3 and Tr1-like cells. TGF-ß produced by these cells could enhance the differentiation of induced regulatory iTreg and iTreg17 cells to prevent induction and progression of autoimmune diseases. We therefore suggest that peripheral immune tolerance could be induced and maintained by immunization with self-peptides that induce TGF-ß producing T cells.

Citrus polymethoxylated flavones improve lipid and glucose homeostasis and modulate adipocytokines in fructose-induced insulin resistant hamsters.

The present study was undertaken to determine whether supplementation with polymethoxylated flavones (PMFs) could ameliorate the fructose-induced hypertriglyceridemia and other metabolic abnormalities associated with insulin resistance (IR) in hamsters. Following feeding with the fructose diet, hamsters were supplemented orally with PMF-L or PMF-H (62.5 and 125 mg/kg/day) for 4 weeks. Both PMF-treated groups showed a statistically significant (p<0.05) decrease in serum triglyceride (TG) and cholesterol levels compared to the fructose-fed control group. The fructose control group at the end of the study showed elevated serum insulin and impaired insulin sensitivity (glucose intolerance). On the other hand, PMF-supplemented groups showed a reversal in these metabolic defects, including a decrease in insulin level and an improvement in glucose tolerance. PMF supplementation also reduced TG contents in the liver and heart and was able to regulate adipocytokines by significantly suppressing TNF-alpha, INF-gamma, IL-1beta and IL-6 expression and increasing adiponectin in IR hamsters. The mechanism of PMF on the activation of peroxisome proliferator-activated receptors (PPAR) was also explored. PMF-H supplementation significantly increased PPARalpha and PPARgamma protein expression in the liver. This is the first report of positive effects of PMF on adipocytokine production and on PPAR expression in IR hamsters. This study suggests that PMF can ameliorate hypertriglyceridemia and its anti-diabetic effects may occur as a consequence of adipocytokine regulation and PPARalpha and PPARgamma activation.

A novel mechanism of regulatory T cell-mediated down-regulation of autoimmunity.

We have established a novel CD4 and CD8 double-positive CD25+ T regulatory (Treg) clone, MT-5B, from lymph nodes of type 1 diabetes prone non-obese diabetic (NOD) mice immunized with CFA. CFA has previously been shown to prevent the onset of diabetes by inducing Treg cells. In vitro, clone MT-5B was anergic to a panel of antigen stimulations and exerted an immunosuppressive effect in antigen-non-specific and cell contact-independent manners. In vivo, clone MT-5B blocked the adoptive transfer of diabetes. Proteomics and immunoadsorption studies identified the suppressive proteins secreted by clone MT-5B as granzyme B (GrB) and perforin (PFN). GrB-mediated immune suppression was PFN dependent. Removal of GrB or PFN from the culture supernatant (SN) of MT-5B cells or pre-incubation of MT-5B cells with ethyleneglycol-bis(aminoethylether)-tetraacetic acid which blocks PFN activity reduced the immunosuppressive effect in vitro. Pre-incubation of diabetogenic splenocytes from NOD mice with MT-5B SN impaired their ability to transfer disease by inducing T cell apoptosis, and removal of GrB from MT-5B SN by immunoadsorption decreased the effector function of MT-5B SN on diabetogenic splenocytes. Immunization of NOD mice with CFA increased the expression of GrB+ CD4 T cells, indicating that these cells are present in vivo. In conclusion, we describe a novel mechanism of cell contact-independent immune suppression in which Treg cells maintain immune homeostasis by secreting GrB/PFN.

Identification of CD4+ T cell-specific epitopes of islet-specific glucose-6-phosphatase catalytic subunit-related protein: a novel beta cell autoantigen in type 1 diabetes.

Islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) has been identified as a novel CD8(+) T cell-specific autoantigen in NOD mice. This study was undertaken to identify MHC class II-specific CD4(+) T cell epitopes of IGRP. Peptides named P1, P2, P3, P4, P5, P6, and P7 were synthesized by aligning the IGRP protein amino acid sequence with peptide-binding motifs of the NOD MHC class II (I-A(g7)) molecule. Peptides P1, P2, P3, and P7 were immunogenic and induced both spontaneous and primed responses. IGRP peptides P1-, P2-, P3-, and P7-induced responses were inhibited by the addition of anti-MHC class II (I-A(g7)) Ab, confirming that the response is indeed I-A(g7) restricted. Experiments using purified CD4(+) and CD8(+) T cells from IGRP peptide-primed mice also showed a predominant CD4(+) T cell response with no significant activation of CD8(+) T cells. T cells from P1-, P3-, and P7-primed mice secreted both IFN-gamma and IL-10 cytokines, whereas P2-primed cells secreted only IFN-gamma. Peptides P3 and P7 prevented the development of spontaneous diabetes and delayed adoptive transfer of diabetes. Peptides P1 and P2 delayed the onset of diabetes in both these models. In summary, we have identified two I-A(g7)-restricted CD4(+) T cell epitopes of IGRP that can modulate and prevent the development of diabetes in NOD mice. These results provide the first evidence on the role of IGRP-specific, MHC class II-restricted CD4(+) T cells in disease protection and may help in the development of novel therapies for type 1 diabetes.

CD4+CD25+ regulatory T cells generated in response to insulin B:9-23 peptide prevent adoptive transfer of diabetes by diabetogenic T cells.

NOD mice have a relative deficiency of CD4+CD25+ regulatory T cells that could result in an inability to maintain peripheral tolerance. The aim of this study was to induce the generation of CD4+CD25+ regulatory T cells in response to autoantigens to prevent type 1 diabetes (T1D). We found that immunization of NOD mice with insulin B-chain peptide B:9-23 followed by 72 h in vitro culture with B:9-23 peptide induces generation of CD4+CD25+ regulatory T cells. Route of immunization has a critical role in the generation of these cells. Non-autoimmune mice BALB/c, C57BL/6 and NOR did not show up regulation of CD4+CD25+ regulatory T cells. These cells secreted large amounts of TGF-beta and TNF-alpha with little or no IFN-gamma and IL-10. Adoptive transfer of these CD4+CD25+ regulatory T cells into NOD-SCID mice completely prevented the adoptive transfer of disease by diabetogenic T cells. Although, non-self antigenic OVA (323-339) peptide immunization and in vitro culture with OVA (323-339) peptide does result in up regulation of CD4+CD25+ T cells, these cells did not prevent transfer of diabetes. Our study for the first time identified the generation of antigen-specific CD4+CD25+ regulatory T cells specifically in response to immunization with B:9-23 peptide in NOD mice that are capable of blocking adoptive transfer of diabetes. Our results suggest the possibility of using autoantigens to induce antigen-specific regulatory T cells to prevent and regulate autoimmune diabetes.