Differences in Tumor Microenvironment Dictate T Helper Lineage Polarization and Response to Immune Checkpoint Therapy.

Immune checkpoint therapy (ICT) shows encouraging results in a subset of patients with metastatic castration-resistant prostate cancer (mCRPC) but still elicits a sub-optimal response among those with bone metastases. Analysis of patients' bone marrow samples revealed increased Th17 instead of Th1 subsets after ICT. To further evaluate the different tumor microenvironments, we injected mice with prostate tumor cells either subcutaneously or intraosseously. ICT in the subcutaneous CRPC model significantly increases intra-tumoral Th1 subsets and improves survival. However, ICT fails to elicit an anti-tumor response in the bone CRPC model despite an increase in the intra-tumoral CD4 T cells, which are polarized to Th17 rather than Th1 lineage. Mechanistically, tumors in the bone promote osteoclast-mediated bone resorption that releases TGF-ß, which restrains Th1 lineage development. Blocking TGF-ß along with ICT increases Th1 subsets and promotes clonal expansion of CD8 T cells and subsequent regression of bone CRPC and improves survival.

Cancer-Germline Antigen Expression Discriminates Clinical Outcome to CTLA-4 Blockade.

CTLA-4 immune checkpoint blockade is clinically effective in a subset of patients with metastatic melanoma. We identify a subcluster of MAGE-A cancer-germline antigens, located within a narrow 75 kb region of chromosome Xq28, that predicts resistance uniquely to blockade of CTLA-4, but not PD-1. We validate this gene expression signature in an independent anti-CTLA-4-treated cohort and show its specificity to the CTLA-4 pathway with two independent anti-PD-1-treated cohorts. Autophagy, a process critical for optimal anti-cancer immunity, has previously been shown to be suppressed by the MAGE-TRIM28 ubiquitin ligase in vitro. We now show that the expression of the key autophagosome component LC3B and other activators of autophagy are negatively associated with MAGE-A protein levels in human melanomas, including samples from patients with resistance to CTLA-4 blockade. Our findings implicate autophagy suppression in resistance to CTLA-4 blockade in melanoma, suggesting exploitation of autophagy induction for potential therapeutic synergy with CTLA-4 inhibitors.

PD-L1:CD80 Cis-Heterodimer Triggers the Co-stimulatory Receptor CD28 While Repressing the Inhibitory PD-1 and CTLA-4 Pathways.

Combined immunotherapy targeting the immune checkpoint receptors cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death 1 (PD-1), or CTLA-4 and the PD-1 ligand (PD-L1) exhibits superior anti-tumor responses compared with single-agent therapy. Here, we examined the molecular basis for this synergy. Using reconstitution assays with fluorescence readouts, we found that PD-L1 and the CTLA-4 ligand CD80 heterodimerize in cis but not trans. Quantitative biochemistry and cell biology assays revealed that PD-L1:CD80 cis-heterodimerization inhibited both PD-L1:PD-1 and CD80:CTLA-4 interactions through distinct mechanisms but preserved the ability of CD80 to activate the T cell co-stimulatory receptor CD28. Furthermore, PD-L1 expression on antigen-presenting cells (APCs) prevented CTLA-4-mediated trans-endocytosis of CD80. Atezolizumab (anti-PD-L1), but not anti-PD-1, reduced cell surface expression of CD80 on APCs, and this effect was negated by co-blockade of CTLA-4 with ipilimumab (anti-CTLA-4). Thus, PD-L1 exerts an immunostimulatory effect by repressing the CTLA-4 axis; this has implications to the synergy of anti-PD-L1 and anti-CTLA-4 combination therapy.

An anti-CTLA-4 heavy chain-only antibody with enhanced Treg depletion shows excellent preclinical efficacy and safety profile.

The value of anti-CTLA-4 antibodies in cancer therapy is well established. However, the broad application of currently available anti-CTLA-4 therapeutic antibodies is hampered by their narrow therapeutic index. It is therefore challenging and attractive to develop the next generation of anti-CTLA-4 therapeutics with improved safety and efficacy. To this end, we generated fully human heavy chain-only antibodies (HCAbs) against CTLA-4. The hIgG1 Fc domain of the top candidate, HCAb 4003-1, was further engineered to enhance its regulatory T (Treg) cell depletion effect and to decrease its half-life, resulting in HCAb 4003-2. We tested these HCAbs in in vitro and in vivo experiments in comparison with ipilimumab and other anti-CTLA4 antibodies. The results show that human HCAb 4003-2 binds human CTLA-4 with high affinity and potently blocks the binding of B7-1 (CD80) and B7-2 (CD86) to CTLA-4. The results also show efficient tumor penetration. HCAb 4003-2 exhibits enhanced antibody-dependent cellular cytotoxicity function, lower serum exposure, and more potent anti-tumor activity than ipilimumab in murine tumor models, which is partly driven by a substantial depletion of intratumoral Tregs. Importantly, the enhanced efficacy combined with the shorter serum half-life and less systemic drug exposure in vivo potentially provides an improved therapeutic window in cynomolgus monkeys and preliminary clinical applications. With its augmented efficacy via Treg depletion and improved safety profile, HCAb 4003-2 is a promising candidate for the development of next generation anti-CTLA-4 therapy.

Effect of CTLA-4 Inhibition on Inflammation and Apoptosis After Spinal Cord Injury.

Spinal cord injury (SCI) encompasses various pathological processes, notably neuroinflammation and apoptosis, both of which play significant roles. CTLA-4, a well-known immune molecule that suppresses T cell-mediated immune responses, is a key area of research and a focal point for targeted therapy development in treating tumors and autoimmune disorders. Despite its prominence, the impact of CTLA-4 inhibition on inflammation and apoptosis subsequent to SCI remains unexplored. This study aimed to investigate the influence of CTLA-4 on SCI. A weight-drop technique was used to establish a rat model of SCI. To examine the safeguarding effect of CTLA-4 on the restoration of motor function in rats with SCI, the Basso-Beattie-Bresnahan (BBB) scale and inclined plane test were employed to assess locomotion. Neuronal degeneration and apoptosis were assessed using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) and Fluoro-Jade B labeling, respectively, and the activity of microglial cells was examined by immunofluorescence. To evaluate the impact of CTLA4 on SCI, the levels of inflammatory markers were measured. After treatment with the CTLA-4 inhibitor ipilimumab, the rats showed worse neurological impairment and more severe neuroinflammation after SCI. Furthermore, the combination therapy with ipilimumab and durvalumab after SCI had more pronounced effects than treatment with either inhibitor alone. These findings indicate that CTLA-4 contributes to neuroinflammation and apoptosis after SCI, presenting a promising new therapeutic target for this traumatic condition.

Comparative Effectiveness of Front-Line Ipilimumab and Nivolumab or Axitinib and Pembrolizumab in Metastatic Clear Cell Renal Cell Carcinoma.

BACKGROUND: Treatment of metastatic renal cell carcinoma (mRCC) is rapidly evolving with new combination therapies demonstrating improved response rates and survival. There are no head-to-head prospective trials comparing an immunotherapy doublet with an immunotherapy/tyrosine-kinase inhibitor-based combination. We compare real-world outcomes in patients treated with axitinib/pembrolizumab (axi/pembro) or ipilimumab/nivolumab (ipi/nivo). The primary endpoints were overall-survival (OS) and real-world progression-free survival (rwPFS). PATIENTS AND METHODS: We used a de-identified database to select patients diagnosed with clear cell mRCC and treated with front-line axi/pembro or ipi/nivo from 2018 to 2022. Analyses are adjusted using propensity score-based inverse probability of treatment weighting, balancing age, gender, insurance, race, IMDC risk, and nephrectomy status. We compared survival by treatment groups using weighted and unweighted Kaplan-Meier curves with log-rank tests and weighted Cox proportional hazards regressions. RESULTS: We included a total of 1506 patients with mRCC who received frontline axi/pembro (n = 547) or ipi/nivo (n = 959). Median follow-up time was 20.0 months (range: 0.2-47.6). Baseline demographics were similar between the 2 cohorts. Adjusted median OS for the full population was 28.9 months for axi/pembro and was 24.3 months for ipi/nivo (P = .09). Twenty-four-month survival was 53.8% for axi/pembro treated patients and 50.2% for ipi/nivo treated patients. rwPFS was 10.6 months for axi/pembro treated patients and 6.9 months for ipi/nivo treated patients. Treatment with axi/pembro conferred improved survival in the IMDC favorable risk strata, with no significant difference in survival observed within the full cohort. CONCLUSIONS: In this retrospective, real-world study of patients treated with front-line combination therapy, patients with IMDC favorable risk disease had better survival when treated with axi/pembro compared to ipi/nivo. However, survival for the entire population and the 24-month median overall survival were not statistically different between treatment groups. Longer follow-up is necessary to discern any emerging significant differences.

A Tumor and Immune-Related Micro-RNA Signature Predicts Relapse-Free Survival of Melanoma Patients Treated with Ipilimumab.

Despite the unprecedented advances in the treatment of melanoma with immunotherapy, there continues to be a major need for biomarkers of clinical benefits and immune resistance associated with immune checkpoint inhibitors; microRNA could play a vital role in these efforts. This study planned to identify differentially expressed miRNA molecules that may have prognostic value for clinical benefits. Patients with surgically operable regionally advanced melanoma were treated with neoadjuvant ipilimumab (10 mg/kg intravenously every 3 weeks × two doses) bracketing surgery. Tumor biospecimens were obtained at baseline and surgery, and microRNA (miRNA) expression profiling was performed on the tumor biopsies. We found that an expression profile consisting of a 4-miRNA signature was significantly associated with improved relapse-free survival (RFS). The signature consisted of biologically relevant molecules previously reported to have prognostic value in melanoma and other malignancies, including miR-34c, miR-711, miR-641, and miR-22. Functional annotation analysis of target genes for the 4-miRNA signature was significantly enriched for various cancer-related pathways, including cell proliferation regulation, apoptosis, the MAPK signaling pathway, and the positive regulation of T cell activation. Our results presented miRNAs as potential biomarkers that can guide the treatment of melanoma with immune checkpoint inhibitors. These findings warrant further investigation in relation to CTLA4 blockade and other immune checkpoint inhibitors. ClinicalTrials.gov NCT00972933.

Response to Nivolumab and Ipilimumab in Microsatellite Instability-High (MSI-H) Cervical Carcinoma with Acquired Resistance to Pembrolizumab: A Case Report and Literature Review.

As the use of immune checkpoint inhibitors (ICIs) in treating a variety of cancer types has increased in recent years, so too have the number of reports on patients acquiring resistance to these therapies. Overcoming acquired resistance to immunotherapy remains an important need in the field of immuno-oncology. Herein, we present a case that suggests sequential administration of combination immunotherapy may be beneficial to advanced cervical cancer patients exhibiting acquired resistance to mono-immunotherapy. The patient's tumor is microsatellite instability-high (MSI-H), which is an important biomarker in predicting ICI response. Results from recent interim prospective studies using combination immunotherapy (eg, nivolumab and ipilimumab) with anti-PD-1 plus anti-CTLA-4 inhibitor following progression on anti-PD-1 inhibitors (eg, nivolumab) have shown anti-tumor activity in patients with advanced melanoma and metastatic urothelial carcinoma. We also introduce retrospective studies and case reports/case series of dual checkpoint inhibition with anti-PD-1 inhibitor plus anti-CTLA-4 inhibitor after progression on prior anti-PD/PD-L1 monotherapy. To date, there has been no prospective study on the use of combined anti-PD-1 and anti-CTLA-4 therapy at the time of progression on anti-PD-1 therapy in patients with MSI-H tumors or advanced cervical cancer. In this report, we provide evidence that supports future investigations into such treatments.

Fc-independent functions of anti-CTLA-4 antibodies contribute to anti-tumor efficacy.

Ipilimumab, a monoclonal antibody that recognizes cytotoxic T-lymphocyte associated protein 4 (CTLA-4), was the first immune checkpoint inhibitor approved by the FDA to treat metastatic melanoma patients. Multiple preclinical studies have proposed that Fc effector functions of anti-CTLA-4 therapy are required for anti-tumor efficacy, in part, through the depletion of intratumoral regulatory T cells (Tregs). However, the contribution of the Fc-independent functions of anti-CTLA-4 antibodies to the observed efficacy is not fully understood. H11, a non-Fc-containing single-domain antibody (VHH) against CTLA-4, has previously been demonstrated to block CTLA-4-ligand interaction. However, in vivo studies demonstrated lack of anti-tumor efficacy with H11 treatment. Here, we show that a half-life extended H11 (H11-HLE), despite the lack of Fc effector functions, induced potent anti-tumor efficacy in mouse syngeneic tumor models. In addition, a non-Fc receptor binding version of ipilimumab (Ipi-LALAPG) also demonstrated anti-tumor activity in the absence of Treg depletion. Thus, we demonstrate that Fc-independent functions of anti-CTLA-4 antibodies contributed to anti-tumor efficacy, which may indicate that non-Treg depleting activity of anti-CTLA-4 therapy could benefit cancer patients in the clinic.

Characterization of the T cell receptor repertoire and melanoma tumor microenvironment upon combined treatment with ipilimumab and hTERT vaccination.

BACKGROUND: This clinical trial evaluated a novel telomerase-targeting therapeutic cancer vaccine, UV1, in combination with ipilimumab, in patients with metastatic melanoma. Translational research was conducted on patient-derived blood and tissue samples with the goal of elucidating the effects of treatment on the T cell receptor repertoire and tumor microenvironment. METHODS: The trial was an open-label, single-center phase I/IIa study. Eligible patients had unresectable metastatic melanoma. Patients received up to 9 UV1 vaccinations and four ipilimumab infusions. Clinical responses were assessed according to RECIST 1.1. Patients were followed up for progression-free survival (PFS) and overall survival (OS). Whole-exome and RNA sequencing, and multiplex immunofluorescence were performed on the biopsies. T cell receptor (TCR) sequencing was performed on the peripheral blood and tumor tissues. RESULTS: Twelve patients were enrolled in the study. Vaccine-specific immune responses were detected in 91% of evaluable patients. Clinical responses were observed in four patients. The mPFS was 6.7 months, and the mOS was 66.3 months. There was no association between baseline tumor mutational burden, neoantigen load, IFN-γ gene signature, tumor-infiltrating lymphocytes, and response to therapy. Tumor telomerase expression was confirmed in all available biopsies. Vaccine-enriched TCR clones were detected in blood and biopsy, and an increase in the tumor IFN-γ gene signature was detected in clinically responding patients. CONCLUSION: Clinical responses were observed irrespective of established predictive biomarkers for checkpoint inhibitor efficacy, indicating an added benefit of the vaccine-induced T cells. The clinical and immunological read-out warrants further investigation of UV1 in combination with checkpoint inhibitors. Trial registration Clinicaltrials.gov identifier: NCT02275416. Registered October 27, 2014. https://clinicaltrials.gov/ct2/show/NCT02275416?term=uv1&draw=2&rank=6.

Effects of Nivolumab and Ipilimumab on the suppression of cisplatin resistant small cell lung cancer cells.

BACKGROUND: Small cell lung cancer (SCLC) accounts for nearly 10-15% of all lung cancer cases. Although many chemotherapy drugs, such as cisplatin and etoposide, were approved as primary therapy for SCLC patients, the prognosis is poor. In this study, we aimed to explore novel therapeutic strategy against SCLC. METHODS: Two SCLC cell lines, LTEP-P and LTEP-P/DDP1.0, were treated with cisplatin, in the absence or presence of Nivolumab + Ipilimumab combination, and the cell viability was measured. Tumor size and mouse survival rate were examined upon different drug treatments. Protein levels of PD-1 and CTLA4 were detected in normal and SCLC cells by Western blot. Cellular cytotoxicity induced by T lymphocytes was measured by thymidine incorporation assay. Tumor infiltrated T cell populations from LTEP-P and LTEP/DDP1.0 tumor-bearing mice were analyzed by flow cytometry. RESULTS: LTEP-P cells, but not LTEP/DDP1.0 cells, exhibited decreased cell viability upon cisplatin, Nivolumab and Ipilimumab combinational treatment. T lymphocytes significantly inhibited the growth of LTEP-P cells in the presence of nivolumab and ipilimumab. The combinational therapy improved survival rate and inhibited tumor growth in LTEP-P tumor-bearing mice, but showed no effect on LTEP/DDP1.0 tumor-bearing mice. Nivolumab and Ipilimumab synergized with cisplatin in increasing CD8 + and CD4 + T cell population, while decreasing Treg population in LTEP-P tumor-bearing mice. CONCLUSIONS: The combinational therapy by cisplatin, Nivolumab and Ipilimumab could be an effective strategy against LTEP-P cells, accompanied with increased cytotoxic T cell populations, but has no significant effect against DDP-resistant lung adenocarcinoma cells.

Cytotoxic T lymphocyte antigen-4 regulates development of xenogenic graft versus host disease in mice via modulation of host immune responses induced by changes in human T cell engraftment and gene expression.

Graft versus host disease (GvHD) is a major clinical problem with a significant unmet medical need. We examined the role of cytotoxic T lymphocyte antigen-4 (CTLA-4) in a xenogenic GvHD (xeno-GvHD) model induced by injection of human peripheral mononuclear cells (hPBMC) into irradiated non-obese diabetic (NOD) SCID gamma (NSG) mice. Targeting the CTLA-4 pathway by treatment with CTLA-4 immunoglobulin (Ig) prevented xeno-GvHD, while anti-CTLA-4 antibody treatment exacerbated the lethality and morbidity associated with GvHD. Xeno-GvHD is associated with infiltration of hPBMCs into the lungs, spleen, stomach, liver and colon and an increase in human proinflammatory cytokines, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-5. Infiltration of donor cells and increases in cytokines were attenuated by treatment with CTLA-4 Ig, but remained either unaffected or enhanced by anti-CTLA-4 antibody. Further, splenic human T cell phenotyping showed that CTLA-4 Ig treatment prevented the engraftment of human CD45+ cells, while anti-CTLA-4 antibody enhanced donor T cell expansion, particularly CD4+ (CD45RO+ ) subsets, including T box transcription factor TBX21 (Tbet)+ CXCR3+ and CD25+ forkhead box protein 3 (FoxP3) cells. Comprehensive analysis of transcriptional profiling of human cells isolated from mouse spleen identified a set of 417 differentially expressed genes (DEGs) by CTLA-4 Ig treatment and 13 DEGs by anti-CTLA-4 antibody treatment. The CTLA-4 Ig regulated DEGs mapped to down-regulated apoptosis, inflammasome, T helper type 17 (Th17) and regulatory T cell (Treg ) pathways and enhanced Toll-like receptor (TLR) receptor signaling, TNF family signaling, complement system and epigenetic and transcriptional regulation, whereas anti-CTLA-4 antibody produced minimal to no impact on these gene pathways. Our results show an important role of co-inhibitory CTLA-4 signaling in xeno-GvHD and suggest the therapeutic utility of other immune checkpoint co-inhibitory pathways in the treatment of immune-mediated diseases driven by hyperactive T cells.

Quantum binding energies of checkpoint CTLA-4 in complex with the immuno-oncological drug ipilimumab.

Inhibition of the checkpoint protein CTLA-4 by the US-FDA's approved monoclonal antibody ipilimumab has delivered breakthrough therapies against a wide range of cancers, being an important issue for clinical research. To date, many structural properties of this drug have been unveiled. However, the binding energy features of the receptor CTLA-4 in complex with its drug inhibitor, based on crystallographic data, need a deeper understanding. Within this context, by employing quantum chemistry we investigate in silico the binding energy features of the checkpoint protein CTLA-4 in complex with its drug inhibitor, highlighting the most relevant residue-residue interactions, looking for new insights into the mechanisms of pathway blockade to further engineer its affinity and selectivity. Our computational results not only give a better understanding of the binding mechanisms, but also point to an efficient alternative towards the development of antibody-based drugs, leading to new treatments for cancer therapy based upon immunotherapy.

Survival Outcomes After Metastasectomy in Melanoma Patients Categorized by Response to Checkpoint Blockade.

INTRODUCTION: Checkpoint inhibitors have improved outcomes in metastatic melanoma, with 4-year overall survival (OS) of 46% for anti-PD-1 alone or 53% in combination with anti-CTLA-4. However, the median progression free survival is 6.9 and 11.5 months, respectively. Many who progress have gone on to alternative treatments, including surgery, yet the outcome of patients selected for surgery after checkpoint blockade remains unclear. METHODS: Patients who were treated with checkpoint blockade from 2003 to 2017, followed by metastasectomy, were identified from a prospectively maintained institutional melanoma database. Response to immunotherapy was assessed at the time of surgery. Patients were categorized as having responding, isolated progressing, or multiple progressing lesions. RESULTS: Of the 237 total patients identified, 208 (88%) had stage IV disease, and 29 (12%) had unresectable stage III disease at the start of immunotherapy. Median OS following first resection was 21 months. Median follow-up among survivors was 23 months. Complete resection at the first operation (n = 87, 37%) was associated with improved survival compared with patients with incomplete resection (n = 150, 63%) [median OS not reached (NR) vs. 10.8 months, respectively; 95% CI: 7.3, 14.8; p < 0.0001]. Patients resected for an isolated progressing or responding tumor had a longer median survival compared with those with multiple progressing lesions (NR vs. 7.8 months, 95% CI: 6.2, 11.2; p < 0.0001). CONCLUSIONS: Patients selected for surgical resection following checkpoint blockade have a relatively favorable survival, especially if they had a response to immunotherapy and undergo complete resection of isolated progressing or responding disease.

Structural basis for cancer immunotherapy by the first-in-class checkpoint inhibitor ipilimumab.

Rational modulation of the immune response with biologics represents one of the most promising and active areas for the realization of new therapeutic strategies. In particular, the use of function blocking monoclonal antibodies targeting checkpoint inhibitors such as CTLA-4 and PD-1 have proven to be highly effective for the systemic activation of the human immune system to treat a wide range of cancers. Ipilimumab is a fully human antibody targeting CTLA-4 that received FDA approval for the treatment of metastatic melanoma in 2011. Ipilimumab is the first-in-class immunotherapeutic for blockade of CTLA-4 and significantly benefits overall survival of patients with metastatic melanoma. Understanding the chemical and physical determinants recognized by these mAbs provides direct insight into the mechanisms of pathway blockade, the organization of the antigen-antibody complexes at the cell surface, and opportunities to further engineer affinity and selectivity. Here, we report the 3.0 Å resolution X-ray crystal structure of the complex formed by ipilimumab with its human CTLA-4 target. This structure reveals that ipilimumab contacts the front ß-sheet of CTLA-4 and intersects with the CTLA-4:Β7 recognition surface, indicating that direct steric overlap between ipilimumab and the B7 ligands is a major mechanistic contributor to ipilimumab function. The crystallographically observed binding interface was confirmed by a comprehensive cell-based binding assay against a library of CTLA-4 mutants and by direct biochemical approaches. This structure also highlights determinants responsible for the selectivity exhibited by ipilimumab toward CTLA-4 relative to the homologous and functionally related CD28.

Increase in Efficacy of Checkpoint Inhibition by Cytokine-Induced-Killer Cells as a Combination Immunotherapy for Renal Cancer.

Cytokine-induced killer (CIK) cells are heterogeneous, major histocompatibility complex (MHC)-unrestricted T lymphocytes that have acquired the expression of several natural killer (NK) cell surface markers following the addition of interferon gamma (IFN-γ), OKT3 and interleukin-2 (IL-2). Treatment with CIK cells demonstrates a practical approach in cancer immunotherapy with limited, if any, graft versus host disease (GvHD) toxicity. CIK cells have been proposed and tested in many clinical trials in cancer patients by autologous, allogeneic or haploidentical administration. The possibility of combining them with specific monoclonal antibodies nivolumab and ipilimumab will further expand the possibility of their clinical utilization. Initially, phenotypic analysis was performed to explore CD3, CD4, CD56, PD-1 and CTLA-4 expression on CIK cells and PD-L1/PD-L2 expression on tumor cells. We further treated CIK cells with nivolumab and ipilimumab and measured the cytotoxicity of CIK cells cocultured to renal carcinoma cell lines, A-498 and Caki-2. We observed a significant decrease in viability of renal cell lines after treating with CIK cells (p < 0.0001) in comparison to untreated renal cell lines and anti-PD-1 or anti-CTLA-4 treatment had no remarkable effect on the viability of tumor cells. Using CCK-8, Precision Count Beads™ and Cell Trace™ violet proliferation assays, we proved significant increased proliferation of CIK cells in the presence of a combination of anti-PD-1 and anti-CTLA-4 antibodies compared to untreated CIK cells. The IFN-γ secretion increased significantly in the presence of A-498 and combinatorial blockade of PD-1 and CTLA-4 compared to nivolumab or ipilimumab monotreatment (p < 0.001). In conclusion, a combination of immune checkpoint inhibition with CIK cells augments cytotoxicity of CIK cells against renal cancer cells.

A Cost-Effectiveness Analysis of Nivolumab and Ipilimumab Versus Sunitinib in First-Line Intermediate- to Poor-Risk Advanced Renal Cell Carcinoma.

BACKGROUND: The treatment paradigm of advanced renal cell carcinoma (RCC) has changed rapidly in recent years. In first-line treatment of intermediate- to poor-risk patients, the CheckMate 214 study demonstrated a significant survival advantage for nivolumab and ipilimumab versus sunitinib. The high cost of combined immune-modulating agents warrants an understanding of the combination's value by considering both efficacy and cost. The objective of this study was to estimate the cost-effectiveness of nivolumab and ipilimumab compared with sunitinib for first-line treatment of intermediate- to poor-risk advanced RCC from the U.S. payer perspective. MATERIALS AND METHODS: A Markov model was developed to compare the costs and effectiveness of nivolumab and ipilimumab with those of sunitinib in the first-line treatment of intermediate- to poor-risk advanced RCC. Health outcomes were measured in life-years and quality-adjusted life-years (QALYs). Drug costs were based on Medicare reimbursement rates in 2017. We extrapolated survival beyond the trial closure using Weibull distribution. Model robustness was addressed in univariable and probabilistic sensitivity analyses. RESULTS: The total mean cost per-patient of nivolumab and ipilimumab versus sunitinib was $292,308 and $169,287, respectfully. Nivolumab and ipilimumab generated a gain of 0.978 QALYs over sunitinib. The incremental cost-effectiveness ratio (ICER) for nivolumab and ipilimumab was $125,739/QALY versus sunitinib. CONCLUSION: Our analysis established that the base case ICER in the model for nivolumab and ipilimumab versus sunitinib is below what some would consider the upper limit of the theoretical willingness-to-pay threshold in the U.S. ($150,000/QALY) and is thus estimated to be cost-effective. IMPLICATIONS FOR PRACTICE: This article assessed the cost-effectiveness of nivolumab and ipilimumab versus sunitinib for treatment of patients with intermediate- to poor-risk metastatic kidney cancer, from the U.S. payer perspective. It would cost $125,739 to gain 1 quality-adjusted life-year with nivolumab and ipilimumab versus sunitinib in these patients.

Major pathologic response on biopsy (MPRbx) in patients with advanced melanoma treated with anti-PD-1: evidence for an early, on-therapy biomarker of response.

BACKGROUND: With increasing anti-PD-1 therapy use in patients with melanoma and other tumor types, there is interest in developing early on-treatment biomarkers that correlate with long-term patient outcome. An understanding of the pathologic features of immune-mediated tumor regression is key in this endeavor. MATERIALS AND METHODS: Histologic features of immune-related pathologic response (irPR) following anti-PD-1 therapy were identified on hematoxylin and eosin (H&E)-stained slides in a discovery cohort of pre- and on-treatment specimens from n = 16 patients with advanced melanoma. These features were used to generate an irPR score [from 0 = no irPR features to 3 = major pathologic response on biopsy (MPRbx, ≤10% residual viable tumor)]. This scoring system was then tested for an association with objective response by RECIST1.1 and overall survival in a prospectively collected validation cohort of pre- and on-treatment biopsies (n = 51 on-treatment at 4-week timepoint) from melanoma patients enrolled on the nivolumab monotherapy arm of CA209-038 (NCT01621490). RESULTS: Specimens from responders in the discovery cohort had features of immune-activation (moderate-high TIL densities, plasma cells) and wound-healing/tissue repair (neovascularization, proliferative fibrosis) compared to nonresponders, (P ≤ 0.021, for each feature). In the validation cohort, increasing irPR score associated with objective response (P = 0.009) and MPRbx associated with increased overall survival (n = 51; HR 0.13; 95%CI, 0.054-0.31, P = 0.015). Neither tumoral necrosis nor pretreatment histologic features were associated with response. Eight of 16 (50%) of patients with stable disease showed irPR features, two of which were MPRbx, indicating a disconnect between pathologic and radiographic features at the 4-week on-therapy timepoint for some patients. CONCLUSIONS: Features of immune-mediated tumor regression on routine H&E-stained biopsy slides from patients with advanced melanoma correlate with objective response to anti-PD-1 and overall survival. An on-therapy biopsy may be particularly clinically useful for informing treatment decisions in patients with radiographic stable disease. This approach is inexpensive, straightforward, and widely available.

Combination of denosumab and immune checkpoint inhibition: experience in 29 patients with metastatic melanoma and bone metastases.

BACKGROUND: PD-1 inhibition (PD-1i) is the standard of care in melanoma and other malignancies. In patients with bone metastases of solid tumors, the monoclonal antibody denosumab directed against RANKL is approved for the prevention of skeletal-related events. However, RANKL is not only relevant in osteoclastogenesis, but also has immunological effects. Hence, we aimed at investigating, whether the combination of PD-1i and denosumab produces synergistic effects in metastatic melanoma treatment. METHODS: We retrospectively collected and analyzed clinical data of metastatic melanoma patients with bone metastases, who received PD-1i and denosumab therapy. RESULTS: 29 patients were identified with a median age of 60.7 years: 20 were male and 9 were female. 20 patients (69%) were in stage IV M1c and 9 (31%) in stage IV M1d; 52% had an increased serum LDH. 24 patients (83%) received PD-1i as first-line therapy and five patients (17%) as second- or third-line therapy. 13 patients received the triple combination nivolumab, ipilimumab and denosumab (N + I+D), 16 patients received PD-1i and denosumab (PD-1i + D). Within a median follow-up time of 19.8 months, 17 patients progressed with a median time to progression of 6 months. The objective response rate was 54% in the N + I + D group and 50% in the PD-1i + D group. Recalcification of bone metastases was radiologically observed in 18 (62%) patients. No unexpected treatment-related adverse events emerged. CONCLUSIONS: The combination therapy of metastatic melanoma with PD-1i and denosumab was feasible without unexpected safety issues and showed a promising efficacy signal. Further investigation in prospective studies is needed.

CTLA-4 antibody ipilimumab negatively affects CD4+ T-cell responses in vitro.

Immune checkpoint inhibitors targeting coinhibitory pathways in T cells possess efficacy in combating cancer. In addition to PD-1/PD-L1 and CTLA-4 antibodies which are already established in tumor immunotherapy, immune checkpoints such as LAG-3 or BTLA are emerging, which may have the potential to enhance T-cell responses alone or in combination with PD-1 blockers. CD4+ T cells play a central role in the immune system and contribute to productive immune responses in multiple ways. The effects of immune checkpoint inhibitors on this cell subset may thus critically influence therapeutic outcomes. Here, we have used in vitro responses to tetanus toxoid (TT) as a model system to study the effects of immune checkpoint inhibitors on CD4+ T-cell responses. CFSE-labeled PBMCs of 65 donors were stimulated with TT in the presence of blocking antibodies to PD-L1, CTLA-4, LAG-3, or BTLA for 7 days. We found that the PD-L1 antibody greatly enhanced cytokine production and antigen-specific CD4+ T-cell proliferation, whereas blocking antibodies to BTLA or LAG-3 did not augment responses to TT. Surprisingly, the presence of the therapeutic CTLA-4 antibody ipilimumab resulted in a significant reduction of CD4+ T-cell proliferation and cytokine production. Stimulation experiments with an IgG4 variant of ipilimumab indicated that the inhibitory effect of ipilimumab was dependent on its IgG1 isotype. Our results indicate that the therapeutic CTLA-4 antibody ipilimumab can impair CD4+ effector T-cell responses and that this activity is mediated by its Fc part and CD16-expressing cells.