Effects of combination treatment with durvalumab plus tremelimumab on the tumor microenvironment in non-small-cell lung carcinoma.

The rapid development of immune checkpoint blockade (ICB) therapies has revolutionized the cancer treatment landscape and brightened the long-term forecast for many cancer patients. However, the specific genomic and proteomic changes in tumors treated with different ICB treatments have yet to be fully characterized. We treated four non-small-cell lung carcinoma (NSCLC) tumor digests ex vivo with the anti-PD-L1 antibody durvalumab (D) alone or in combination with the anti-CTLA-4 antibody tremelimumab (T) to explore changes in gene and protein expression associated with these ICB therapies. All four tumors showed a robust increase in interferon gamma (IFN-γ) production (100-300% higher than isotype control) in both D- and D + T-treated tumors. Three of the four tumors showed additional increases in IFN-γ production with D + T compared with D (40-70%). A substantial reduction in interleukin 10 (IL-10) was also found in three of the four tumors (reduced to 4-8%) in response to D and D + T. Conventional CD4 + /CD8 + populations and T cell activation markers increased after D and D + T treatment. D and D + T upregulated multiple IPA pathways involving T cell activation. D + T resulted in additional upregulation of Th1/Th2 pathways through a different set of genes, as well as greater reduction in genes involved in epithelial-mesenchymal transition (EMT), angiogenesis, and cancer stemness. Our results demonstrated that D + T augmented the effects of D in the microenvironment of this set of NSCLC tumors. The specific impact of D + T on the regulation of EMT, angiogenesis, and cancer stemness warrants further evaluation in a larger set of tumors.

Comparison of immune infiltrates in melanoma and pancreatic cancer highlights VISTA as a potential target in pancreatic cancer.

Immune checkpoint therapy (ICT) has transformed cancer treatment in recent years; however, treatment response is not uniform across tumor types. The tumor immune microenvironment plays a critical role in determining response to ICT; therefore, understanding the differential immune infiltration between ICT-sensitive and ICT-resistant tumor types will help to develop effective treatment strategies. We performed a comprehensive analysis of the immune tumor microenvironment of an ICT-sensitive tumor (melanoma, n = 44) and an ICT-resistant tumor (pancreatic cancer, n = 67). We found that a pancreatic tumor has minimal to moderate infiltration of CD3, CD4, and CD8 T cells; however, the immune infiltrates are predominantly present in the stromal area of the tumor and are excluded from tumoral area compared with melanoma, where the immune infiltrates are primarily present in the tumoral area. Metastatic pancreatic ductal adenocarcinomas (PDACs) had a lower infiltration of total T cells compared with resectable primary PDACs, suggesting that metastatic PDACs have poor immunogenicity. Further, a significantly higher number of CD68+ macrophages and VISTA+ cells (also known as V-domain immunoglobulin suppressor of T cell activation) were found in the pancreatic stromal area compared with melanoma. We identified VISTA as a potent inhibitory checkpoint that is predominantly expressed on CD68+ macrophages on PDACs. These data suggest that VISTA may be a relevant immunotherapy target for effective treatment of patients with pancreatic cancer.

Clonal expansion of CD8 T cells in the systemic circulation precedes development of ipilimumab-induced toxicities.

Immune checkpoint therapies, such as ipilimumab, induce dramatic antitumor responses in a subset of patients with advanced malignancies, but they may also induce inflammatory responses and toxicities termed immune-related adverse events (irAEs). These irAEs are often low grade and manageable, but severe irAEs may lead to prolonged hospitalizations or fatalities. Early intervention is necessary to minimize morbidities that occur with severe irAEs. However, correlative biomarkers are currently lacking. In a phase II clinical trial that treated 27 patients with metastatic prostate cancer, we aimed to test the safety and efficacy of androgen deprivation therapy plus ipilimumab. In this study, we observed grade 3 toxicities in >40% of treated patients, which led to early closure of the study. Because ipilimumab enhances T-cell responses, we hypothesized that increased clonal T-cell responses in the systemic circulation may contribute to irAEs. Sequencing of the T-cell receptor ß-chains in purified T cells revealed clonal expansion of CD8 T cells, which occurred in blood samples collected before the onset of grade 2-3 irAEs. These initial results suggested that expansion of ≥55 CD8 T-cell clones preceded the development of severe irAEs. We further evaluated available blood samples from a second trial and determined that patients who experienced grade 2-3 irAEs also had expansion of ≥55 CD8 T-cell clones in blood samples collected before the onset of irAEs. We propose that CD8 T-cell clonal expansion may be a correlative biomarker to enable close monitoring and early intervention for patients receiving ipilimumab.

A phase II trial of recombinant MAGE-A3 protein with immunostimulant AS15 in combination with high-dose Interleukin-2 (HDIL2) induction therapy in metastatic melanoma.

BACKGROUND: HDIL-2 is approved for advanced melanoma based on its durable antitumor activity. MAGE-A3 cancer immunotherapeutic (MAGE-A3 CI) is a recombinant MAGE-A3 protein combined with an immunostimulant adjuvant system and has shown antitumor activity in melanoma. We assessed the safety and anti-tumor activity of HDIL-2 combined with MAGE-A3 CI in advanced melanoma. METHODS: Patients with unresectable Stage III or Stage IV MAGE-A3-positive melanoma were enrolled in this phase II study. Treatment included an induction phase of MAGE-A3 CI plus HDIL-2 for 8 cycles followed by a maintenance phase of MAGE-A3 CI monotherapy. The primary endpoints were safety and objective response assessed per RECIST v1.1. Immune biomarker and correlative studies on tumor and peripheral blood were performed. RESULTS: Eighteen patients were enrolled. Seventeen patients were evaluable for safety and sixteen for response. Responses occurred in 4/16 (25%) patients with 3 complete responses, and stable disease in 6/16 (38%) patients with a disease control rate of 63%. The median duration of response was not reached at median follow-up of 36.8 months. Induction therapy of HDIL-2 + MAGE-A3 CI had similar toxicities to those reported with HDIL-2 alone. Maintenance MAGE-A3 monotherapy was well-tolerated. Increased immune checkpoint receptor expression by circulating T regulatory cells was associated with poor clinical outcomes; and responders tended to have increased tumor infiltrating T cells in the baseline tumor samples. CONCLUSIONS: The safety profile of HDIL-2 + MAGE-A3 CI was similar to HDIL-2 monotherapy. Maintenance MAGE-A3 CI provides robust anti-tumor activity in patients who achieved disease control with induction therapy. Immune monitoring data suggest that MAGE-A3 CI plus checkpoint inhibitors could be a promising treatment for MAGE-A3-positive melanoma. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01266603 . Registered 12/24/2010, https://clinicaltrials.gov/ct2/show/NCT01266603.

Nivolumab for previously treated unresectable metastatic anal cancer (NCI9673): a multicentre, single-arm, phase 2 study.

BACKGROUND: Squamous cell carcinoma of the anal canal (SCCA) is a rare malignancy associated with infection by human papillomavirus (HPV). No consensus treatment approach exists for the treatment of metastatic disease. Because intratumoral HPV oncoproteins upregulate immune checkpoint proteins such as PD-1 to evade immune-mediated cytotoxicity, we did a trial of the anti-PD-1 antibody nivolumab for patients with metastatic SCCA. METHODS: We did this single-arm, multicentre, phase 2 trial at ten academic centres in the USA. We enrolled patients with treatment-refractory metastatic SCCA, who were given nivolumab every 2 weeks (3 mg/kg). The primary endpoint was response according to Response Evaluation Criteria in Solid Tumors, version 1.1, in the intention-to-treat population. At the time of data cutoff, the study was ongoing, with patients continuing to receive treatment. The study is registered with ClinicalTrials.gov, number NCT02314169. RESULTS: We screened 39 patients, of whom 37 were enrolled and received at least one dose of nivolumab. Among the 37 patients, nine (24% [95% CI 15-33]) had responses. There were two complete responses and seven partial responses. Grade 3 adverse events were anaemia (n=2), fatigue (n=1), rash (n=1), and hypothyroidism (n=1). No serious adverse events were reported. INTERPRETATION: To our knowledge, this is the first completed phase 2 trial of immunotherapy for SCCA. Nivolumab is well tolerated and effective as a monotherapy for patients with metastatic SCCA. Immune checkpoint blockade appears to be a promising approach for patients with this orphan disease. FUNDING: National Cancer Institute/Cancer Therapy Evaluation Program, the HPV and Anal Cancer Foundation, the E B Anal Cancer Fund, The University of Texas MD Anderson Moon Shots Program, and an anonymous philanthropic donor.

Safety and activity of PD1 blockade by pidilizumab in combination with rituximab in patients with relapsed follicular lymphoma: a single group, open-label, phase 2 trial.

BACKGROUND: Endogenous or iatrogenic antitumour immune responses can improve the course of follicular lymphoma, but might be diminished by immune checkpoints in the tumour microenvironment. These checkpoints might include effects of programmed cell death 1 (PD1), a co-inhibitory receptor that impairs T-cell function and is highly expressed on intratumoral T cells. We did this phase 2 trial to investigate the activity of pidilizumab, a humanised anti-PD1 monoclonal antibody, with rituximab in patients with relapsed follicular lymphoma. METHODS: We did this open-label, non-randomised trial at the University of Texas MD Anderson Cancer Center (Houston, TX, USA). Adult (≥18 years) patients with rituximab-sensitive follicular lymphoma relapsing after one to four previous therapies were eligible. Pidilizumab was administered at 3 mg/kg intravenously every 4 weeks for four infusions, plus eight optional infusions every 4 weeks for patients with stable disease or better. Starting 17 days after the first infusion of pidilizumab, rituximab was given at 375 mg/m(2) intravenously weekly for 4 weeks. The primary endpoint was the proportion of patients who achieved an objective response (complete response plus partial response according to Revised Response Criteria for Malignant Lymphoma). Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00904722. FINDINGS: We enrolled 32 patients between Jan 13, 2010, and Jan 20, 2012. Median follow-up was 15.4 months (IQR 10.1-21.0). The combination of pidilizumab and rituximab was well tolerated, with no autoimmune or treatment-related adverse events of grade 3 or 4. The most common adverse events of grade 1 were anaemia (14 patients) and fatigue (13 patients), and the most common adverse event of grade 2 was respiratory infection (five patients). Of the 29 patients evaluable for activity, 19 (66%) achieved an objective response: complete responses were noted in 15 (52%) patients and partial responses in four (14%). INTERPRETATION: The combination of pidilizumab plus rituximab is well tolerated and active in patients with relapsed follicular lymphoma. Our results suggest that immune checkpoint blockade is worthy of further study in follicular lymphoma. FUNDING: National Institutes of Health, Leukemia and Lymphoma Society, Cure Tech, and University of Texas MD Anderson Cancer Center.

Broad cross-presentation of the hematopoietically derived PR1 antigen on solid tumors leads to susceptibility to PR1-targeted immunotherapy.

PR1 is a HLA-A2-restricted peptide that has been targeted successfully in myeloid leukemia with immunotherapy. PR1 is derived from the neutrophil granule proteases proteinase 3 (P3) and neutrophil elastase (NE), which are both found in the tumor microenvironment. We recently showed that P3 and NE are taken up and cross-presented by normal and leukemia-derived APCs, and that NE is taken up by breast cancer cells. We now extend our findings to show that P3 and NE are taken up and cross-presented by human solid tumors. We further show that PR1 cross-presentation renders human breast cancer and melanoma cells susceptible to killing by PR1-specific CTLs (PR1-CTL) and the anti-PR1/HLA-A2 Ab 8F4. We also show PR1-CTL in peripheral blood from patients with breast cancer and melanoma. Together, our data identify cross-presentation as a novel mechanism through which cells that lack endogenous expression of an Ag become susceptible to therapies that target cross-presented Ags and suggest PR1 as a broadly expressed tumor Ag.

MART-1-specific melanoma tumor-infiltrating lymphocytes maintaining CD28 expression have improved survival and expansion capability following antigenic restimulation in vitro.

We determined how CD8(+) melanoma tumor-infiltrating lymphocytes (TILs) isolated from two distinct phases of expansion in preparation for adoptive T cell therapy respond to melanoma Ag restimulation. We found that TILs isolated after the rapid expansion protocol (REP) phase, used to generate the final patient TIL infusion product, were hyporesponsive to restimulation with MART-1 peptide-pulsed dendritic cells, with many CD8(+) T cells undergoing apoptosis. Telomere length was shorter post-REP, but of sufficient length to support further cell division. Phenotypic analysis revealed that cell-surface CD28 expression was significantly reduced in post-REP TILs, whereas CD27 levels remained unchanged. Tracking post-REP TIL proliferation by CFSE dilution, as well as sorting for CD8(+)CD28(+) and CD8(+)CD28(-) post-REP subsets, revealed that the few CD28(+) TILs remaining post-REP had superior survival capacity and proliferated after restimulation with MART-1 peptide. An analysis of different supportive cytokine mixtures during the REP found that a combination of IL-15 and IL-21 facilitated comparable expansion of CD8(+) TILs as IL-2, but prevented the loss of CD28 expression with improved responsiveness to antigenic restimulation post-REP. These results suggest that current expansion protocols using IL-2 for melanoma adoptive T cell therapy yields largely CD8(+) T cells unable to persist and divide in vivo following Ag contact. The few CD8(+)CD28(+) T cells that remain may be the only CD8(+) TILs that ultimately survive to repopulate the host and mediate long-term tumor control. A REP protocol using IL-15 and IL-21 may greatly increase the number of CD28(+) TILs capable of long-term persistence.

Presurgical stress management improves postoperative immune function in men with prostate cancer undergoing radical prostatectomy.

OBJECTIVE: To assess whether stress management (SM) improved immune outcomes in men undergoing surgery for prostate cancer. METHODS: A total of 159 men were assigned randomly to a two-session presurgical SM intervention, a two-session supportive attention (SA) group, or a standard care (SC) group. Men in the SM group discussed their concerns about the upcoming surgery and were taught diaphragmatic breathing, guided imagery; they had an imaginal exposure to the day of surgery and learned adaptive coping skills. Men in the SA group discussed their concerns about the upcoming surgery and had a semistructured medical interview. Blood samples were collected at baseline (1 month before surgery) and 48 hours after surgery. Measures of mood (Profile of Mood States) were collected at baseline, 1 week pre surgery, and the morning of surgery. RESULTS: Men in the SM group had significantly higher levels of natural killer cell cytotoxicity (p = .04) and higher levels of circulating proinflammatory cytokines (interleukin [IL]-12p70, p = .02; IL-1ß, p = .02; tumor necrosis factor-α, p = .05) 48 hours post surgery than men in the SA group and higher levels of natural killer cell cytotoxicity (p = 0.02) and IL-1ß (p = .05) than men in the SC group. Immune parameters increased for the SM group and decreased or stayed the same for the SA and SC groups. The SM group had significantly lower Profile of Mood States scores than the SC group (p = .006), with no other group differences between SA and SC groups. Changes in mood were not associated with immune outcomes. CONCLUSIONS: The finding that SM leads to decreased presurgical mood-disturbance and increased immune parameters after surgery reveals the potential psychological and biological benefits of presurgical SM.

Gut microbiota signatures are associated with toxicity to combined CTLA-4 and PD-1 blockade.

Treatment with combined immune checkpoint blockade (CICB) targeting CTLA-4 and PD-1 is associated with clinical benefit across tumor types, but also a high rate of immune-related adverse events. Insights into biomarkers and mechanisms of response and toxicity to CICB are needed. To address this, we profiled the blood, tumor and gut microbiome of 77 patients with advanced melanoma treated with CICB, with a high rate of any ≥grade 3 immune-related adverse events (49%) with parallel studies in pre-clinical models. Tumor-associated immune and genomic biomarkers of response to CICB were similar to those identified for ICB monotherapy, and toxicity from CICB was associated with a more diverse peripheral T-cell repertoire. Profiling of gut microbiota demonstrated a significantly higher abundance of Bacteroides intestinalis in patients with toxicity, with upregulation of mucosal IL-1ß in patient samples of colitis and in pre-clinical models. Together, these data offer potential new therapeutic angles for targeting toxicity to CICB.

Circulating tumor antigen-specific regulatory T cells in patients with metastatic melanoma.

Although it is accepted that regulatory T cells (T regs) contribute to cancer progression, most studies in the field consider nonantigen-specific suppression. Here, we show the presence of tumor antigen-specific CD4(+) T regs in the blood of patients with metastatic melanoma. These CD4(+) T regs recognize a broad range of tumor antigens, including gp100 and TRP1 (melanoma tissue differentiation antigens), NY-ESO-1 (cancer/testis antigen) and survivin (inhibitor of apoptosis protein (IAP) family antigen). These tumor antigen-specific T regs proliferate in peripheral blood mononuclear cells (PBMC) cultures in response to specific 15-mer peptides, produce preferentially IL-10 and express high levels of FoxP3. They suppress autologous CD4(+)CD25(-) T cell responses in a cell contact-dependent manner and thus share properties of both naturally occurring regulatory T cells and type 1 regulatory T cells. Such tumor antigen-specific T regs were not detected in healthy individuals. These tumor antigen-specific T regs might thus represent another target for immunotherapy of metastatic melanoma.

Immune profiling of human tumors identifies CD73 as a combinatorial target in glioblastoma.

Immune checkpoint therapy with anti-CTLA-4 and anti-PD-1/PD-L1 has revolutionized the treatment of many solid tumors. However, the clinical efficacy of immune checkpoint therapy is limited to a subset of patients with specific tumor types1,2. Multiple clinical trials with combinatorial immune checkpoint strategies are ongoing; however, the mechanistic rationale for tumor-specific targeting of immune checkpoints is elusive. To garner an insight into tumor-specific immunomodulatory targets, we analyzed 94 patients representing five different cancer types, including those that respond relatively well to immune checkpoint therapy and those that do not, such as glioblastoma multiforme, prostate cancer and colorectal cancer. Through mass cytometry and single-cell RNA sequencing, we identified a unique population of CD73hi macrophages in glioblastoma multiforme that persists after anti-PD-1 treatment. To test if targeting CD73 would be important for a successful combination strategy in glioblastoma multiforme, we performed reverse translational studies using CD73-/- mice. We found that the absence of CD73 improved survival in a murine model of glioblastoma multiforme treated with anti-CTLA-4 and anti-PD-1. Our data identified CD73 as a specific immunotherapeutic target to improve antitumor immune responses to immune checkpoint therapy in glioblastoma multiforme and demonstrate that comprehensive human and reverse translational studies can be used for rational design of combinatorial immune checkpoint strategies.

Neoantigen responses, immune correlates, and favorable outcomes after ipilimumab treatment of patients with prostate cancer.

Tumors with high mutational burden (TMB) tend to be responsive to immune checkpoint blockade (ICB) because there are neoantigens available for targeting by reinvigorated T cells, whereas those with low TMB demonstrate limited clinical responses. To determine whether antigen-specific T cell responses can be elicited after treatment with ICB in cancers that have a low TMB, we conducted a clinical trial with ipilimumab in 30 patients with metastatic castration-resistant prostate cancer. We identified two distinct cohorts by survival and progression times: "favorable" (n = 9) and "unfavorable" (n = 10). Patients in the favorable cohort had high intratumoral CD8 T cell density and IFN-γ response gene signature and/or antigen-specific T cell responses. Two patients with a relatively low TMB had T cell responses against unique neoantigens. Moreover, six of nine patients in the favorable group are still alive at the time of analysis, with survival ranging from 33 to 54 months after treatment. All 10 patients in the unfavorable cohort have succumbed to their disease and had survival ranging from 0.6 to 10.3 months. Collectively, our data indicate that immunological correlates associated with effector T cell responses are observed in patients with metastatic prostate cancer who benefit from ICB.

Window-of-opportunity clinical trial of pembrolizumab in patients with recurrent glioblastoma reveals predominance of immune-suppressive macrophages.

BACKGROUND: We sought to ascertain the immune effector function of pembrolizumab within the glioblastoma (GBM) microenvironment during the therapeutic window. METHODS: In an open-label, single-center, single-arm phase II "window-of-opportunity" trial in 15 patients with recurrent (operable) GBM receiving up to 2 pembrolizumab doses before surgery and every 3 weeks afterward until disease progression or unacceptable toxicities occurred, immune responses were evaluated within the tumor. RESULTS: No treatment-related deaths occurred. Overall median follow-up time was 50 months. Of 14 patients monitored, 10 had progressive disease, 3 had a partial response, and 1 had stable disease. Median progression-free survival (PFS) was 4.5 months (95% CI: 2.27, 6.83), and the 6-month PFS rate was 40%. Median overall survival (OS) was 20 months, with an estimated 1-year OS rate of 63%. GBM patients' recurrent tumors contained few T cells that demonstrated a paucity of immune activation markers, but the tumor microenvironment was markedly enriched for CD68+ macrophages. CONCLUSIONS: Immune analyses indicated that pembrolizumab anti-programmed cell death 1 (PD-1) monotherapy alone can't induce effector immunologic response in most GBM patients, probably owing to a scarcity of T cells within the tumor microenvironment and a CD68+ macrophage preponderance.

Anti-CTLA-4 Immunotherapy Does Not Deplete FOXP3+ Regulatory T Cells (Tregs) in Human Cancers.

PURPOSE: CTLA-4 was the first inhibitory immune checkpoint to be identified. Two mAbs, ipilimumab (IgG1) and tremelimumab (IgG2), which block the function of CTLA-4, have demonstrated durable clinical activity in a subset of patients with advanced solid malignancies by augmenting effector T-cell-mediated immune responses. Studies in mice suggest that anti-CTLA-4 mAbs may also selectively deplete intratumoral FOXP3+ regulatory T cells via an Fc-dependent mechanism. However, it is unclear whether the depletion of FOXP3+ cells occurs in patients with cancer treated with anti-CTLA-4 therapies. EXPERIMENTAL DESIGN: Quantitative IHC was used to evaluate the densities of intratumoral CD4+, CD8+, and FOXP3+ cells in stage-matched melanoma (n = 19), prostate cancer (n = 17), and bladder cancer (n = 9) samples treated with ipilimumab and in paired melanoma tumors (n = 18) treated with tremelimumab. These findings were corroborated with multiparametric mass cytometry analysis of tumor-infiltrating cells from paired fresh melanoma tumors (n = 5) treated with ipilimumab. RESULTS: Both ipilimumab and tremelimumab increase infiltration of intratumoral CD4+ and CD8+ cells without significantly changing or depleting FOXP3+ cells within the tumor microenvironment. CONCLUSIONS: Anti-CTLA-4 immunotherapy does not deplete FOXP3+ cells in human tumors, which suggests that their efficacy could be enhanced by modifying the Fc portions of the mAbs to enhance Fc-mediated depletion of intratumoral regulatory T cells.See related commentary by Quezada and Peggs, p. 1130.

Immunologic Correlates of Pathologic Complete Response to Preoperative Immunotherapy in Hepatocellular Carcinoma.

In hepatocellular carcinoma (HCC), surgical resection is associated with high recurrence rate, and no effective adjuvant therapy currently exists. We initiated a pilot randomized trial of perioperative immunotherapy with nivolumab and ipilimumab for resectable HCC. Here, we provide an illustrative report of a case that achieved a complete response and report immunologic correlates of this complete pathologic response to perioperative immunotherapy. Clinical response was correlated with an increase in CD8+ T-cell infiltration, with an increase in two effector T-cell clusters. This study is ongoing, and the final results may contribute to a paradigm shift in the perioperative treatment of HCC, leading to the incorporation of immunotherapy in the curative setting.

Blockade of CTLA-4 and PD-1 Enhances Adoptive T-cell Therapy Efficacy in an ICOS-Mediated Manner.

Adoptive transfer of tumor-reactive T cells (ACT) has led to modest clinical benefit in the treatment of solid tumors. Failures with this therapy are primarily due to inadequate infiltration and poor function of adoptively transferred cells in the tumor microenvironment. To improve the efficacy of ACT, we combined ACT with dual blockade of CTLA-4 and PD-1. Treatment with anti-CTLA-4 plus anti-PD-1 compared with monotherapy resulted in durable antitumor responses, enhanced effector function of ACT, utilizing PMEL-1 transgenic (Tg+) CD8+ T cells, and improved survival. Using PMEL-1ICOS-/- mice, we showed that deletion of the inducible T-cell costimulator (ICOS) receptor abolished the therapeutic benefits, with selective downregulation of Eomesodermin (Eomes), interferon gamma (IFNγ), and perforin. Higher expression of IFNγ and Eomes was noted in human ICOShi CD8+ T cells compared with ICOSlow counterparts. Together, our data provide direct evidence that ACT combined with immune-checkpoint therapy confers durable antitumor responses, which largely depended on CD8+ T-cell-intrinsic expression of ICOS. Our study provides a foundation of testing combinatorial therapy of ACT of CD8 T cells and dual blocking of CTLA-4 and PD-1 in patients with melanoma.

Characterization and Comparison of GITR Expression in Solid Tumors.

PURPOSE: Determine the differential effect of a FcγR-binding, mIgG2a anti-GITR antibody in mouse tumor models, and characterize the tumor microenvironment for the frequency of GITR expression in T-cell subsets from seven different human solid tumors.Experimental Design: For mouse experiments, wild-type C57BL/6 mice were subcutaneously injected with MC38 cells or B16 cells, and BALB/c mice were injected with CT26 cells. Mice were treated with the anti-mouse GITR agonist antibody 21B6, and tumor burden and survival were monitored. GITR expression was evaluated at the single-cell level using flow cytometry (FC). A total of 213 samples were evaluated for GITR expression by IHC, 63 by FC, and 170 by both in seven human solid tumors: advanced hepatocellular carcinoma, non-small cell lung cancer (NSCLC), renal cell carcinoma, pancreatic carcinoma, head and neck carcinoma, melanoma, and ovarian carcinoma. RESULTS: The therapeutic benefit of 21B6 was greatest in CT26 followed by MC38, and was least in the B16 tumor model. The frequency of CD8 T cells and effector CD4 T cells within the immune infiltrate correlated with response to treatment with GITR antibody. Analysis of clinical tumor samples showed that NSCLC, renal cell carcinoma, and melanoma had the highest proportions of GITR-expressing cells and highest per-cell density of GITR expression on CD4+ Foxp3+ T regulatory cells. IHC and FC data showed similar trends with a good correlation between both techniques. CONCLUSIONS: Human tumor data suggest that NSCLC, renal cell carcinoma, and melanoma should be the tumor subtypes prioritized for anti-GITR therapy development.

A new approach for the large-scale generation of mature dendritic cells from adherent PBMC using roller bottle technology.

BACKGROUND: Human monocyte-derived DC (mDC) loaded with peptides, protein, tumor cell lysates, or tumor cell RNA, are being tested as vaccines against multiple human malignancies and viral infection with great promise. One of the factors that has limited more widespread use of these vaccines is the need to generate mDC in large scale. Current methods for the large-scale cultivation of mDC in static culture vessels are labor- and time- intensive, and also require many culture vessels. Here, we describe a new method for the large-scale generation of human mDC from human PBMC from leukopheresis or buffy coat products using roller bottles, never attempted before for mDC generation. We have tested this technology using 850 cm2 roller bottles compared to conventional T-175 flat-bottom static culture flasks. METHODS: DC were generated from adherent human PBMC from buffy coats or leukopherisis products using GM-CSF and IL-4 in T-175 static flasks or 850 cm2 roller bottles. The cells were matured over two days, harvested and analyzed for cell yield and mature DC phenotype by flow cytometry, and then functionally analyzed for their ability to activate allogeneic T-cell or recall antigen peptide-specific T-cell responses. RESULTS: Monocytes were found to adhere inside roller bottles to the same extent as in static culture flasks. The phenotype and function of the mDC harvested after maturation from both type of culture systems were similar. The yield of mDC from input PBMC in the roller bottle system was similar as in the static flask system. However, each 850 cm2 roller bottle could be seeded with 4-5 times more input PBMC and could yield 4-5 times as many mDC per culture vessel than the static flasks as a result. CONCLUSION: Our results indicate that the roller bottle technology can generate similar numbers of mDC from adherent PBMC as traditional static flask methods, but with having to use fewer culture vessels. Thus, this may be a more practical method to generate mDC in large-scale cutting down on the amount of laboratory manipulations, and can save both time and labor costs.

Ipilimumab plus Lenalidomide after Allogeneic and Autologous Stem Cell Transplantation for Patients with Lymphoid Malignancies.

Purpose: Prevention or treatment of relapsed lymphoid malignancies after hematopoietic stem cell transplantation (HSCT) requires novel strategies. We hypothesized that antitumor-cell responses could be enhanced by the addition of lenalidomide to the cytotoxic T-lymphocyte-associated protein 4 inhibitor ipilimumab.Experimental Design: We conducted a phase II investigator-initiated trial to assess the safety and activity of ipilimumab and lenalidomide in patients with lymphoid malignancies that relapsed after allogeneic HSCT and in high-risk patients after autologous HSCT. Patients received 10 mg of oral lenalidomide daily for 21 days followed by intravenous ipilimumab at 3 mg/kg bodyweight. The regimen was repeated 4 weeks later for a total of four treatments.Results: We enrolled 17 patients (10 allogeneic and seven autologous transplant recipients). Immune-mediated toxicity was limited to one patient with asymptomatic hypothyroidism and one with dermatitis in the allogeneic and autologous groups, respectively. One allogeneic transplant recipient had a flare of prior GVHD while taking lenalidomide that precluded further treatment. All others finished treatment without GVHD. Four of 10 patients in the allogeneic group had complete responses (three of which were durable at 19+, 21+, and 32+ months), and three had partial responses. The disease in six of seven patients in the autologous group remains in remission. The groups had similar immune responses, including a two- to threefold increase in inducible ICOS+CD4+FoxP3- T-cell number.Conclusions: Our early-phase data suggested that ipilimumab plus lenalidomide is well tolerated after HSCT. Adverse events did not differ significantly between the allogeneic and autologous groups. Clin Cancer Res; 24(5); 1011-8. ©2017 AACR.