Efficacy and safety of PD-1 inhibitors for treating advanced melanoma: a systematic review and meta-analysis

Antagonism of regulatory ISGs enhances the anti-melanoma efficacy of STING agonists

Background

Stimulator of Interferon Genes (STING) is a dsDNA sensor that triggers type I inflammatory responses. Recent data from our group and others support the therapeutic efficacy of STING agonists applied intratumorally or systemically in a range of murine tumor models, with treatment benefits associated with tumor vascular normalization and improved immune cell recruitment and function within the tumor microenvironment (TME). However, such interventions are rarely curative and STING agonism coordinately upregulates expression of immunoregulatory interferon-stimulated genes (ISGs) including Arg2, Cox2, Isg15, Nos2, and Pdl1 that may limit treatment benefits. We hypothesized that combined treatment of melanoma-bearing mice with STING agonist ADU-S100 together with antagonists of regulatory ISGs would result in improved control of tumor growth vs. treatment with ADU-S100 alone.

Methods

Mice bearing either B16 (BRAFWTPTENWT) or BPR20 (BRAFV600EPTEN-/-) melanomas were treated with STING agonist ADU-S100 plus various inhibitors of ARG2, COX2, NOS2, PD-L1, or ISG15. Tumor growth control and changes in the TME were evaluated for combination treatment vs ADU-S100 monotherapy by tumor area measurements and flow cytometry/transcriptional profiling, respectively.

Results

In the B16 melanoma model, we noted improved antitumor efficacy only when ADU-S100 was combined with neutralizing/blocking antibodies against PD-L1 or ISG15, but not inhibitors of ARG2, COX2, or NOS2. Conversely, in the BPR20 melanoma model, improved tumor growth control vs. ADU-S100 monotherapy was only observed when combining ADU-S100 with ARG2i, COX2i, and NOS2i, but not anti-PD-L1 or anti-ISG15. Immune changes in the TME associated with improved treatment outcomes were subtle but included increases in proinflammatory innate immune cells and activated CD8+CD69+ T cells and varied between the two tumor models.

Conclusions

These data suggest contextual differences in the relative contributions of individual regulatory ISGs that serve to operationally limit the anti-tumor efficacy of STING agonists which should be considered in future design of novel combination protocols for optimal treatment benefit.

Role of high‑sensitivity C‑reactive protein in patients with sarcoma

Immunotherapy has shown promising results in lung cancer and melanomas; however, the responses have been poor in patients with sarcoma. Understanding the relationship between the immune system and sarcoma is essential to develop improved immunotherapy approaches. High-sensitivity C-reactive protein (hs-CRP) has been proposed as a prognostic marker in other cancer types; however, to the best of our knowledge, the association between hs-CRP levels and mortality in patients with sarcoma has not been investigated. The present prospective, non-randomised, non-interventional explorative study investigated the prognostic value of hs-CRP in patients with sarcoma. Patients referred to the sarcoma centre of Aarhus University Hospital (Aarhus, Denmark) were included between April 2014 and December 2020. Clinical data were obtained from the national quality sarcoma database and biomarkers other than hs-CRP were obtained from the clinical laboratory information system. The study cohort consisted primarily of patients with localised sarcoma. hs-CRP was significantly higher in patients with bone sarcoma (P=0.022) and soft tissue sarcoma (STS; P<0.001) compared with control patients. For STS, grade III tumours but not metastatic disease were associated with a higher hs-CRP level (P=0.0001). Elevated hs-CRP levels were associated with increased overall mortality [hazard ratio (HR), 1.91; 95% CI, 1.33-2.75; P=0.001]. Furthermore, elevated hs-CRP levels were also associated with decreased progression-free survival (HR, 1.64; 95% CI, 1.17-2.29; P=0.004). Furthermore, for patients with hs-CRP <8 mg/l, higher hs-CRP was associated with an increased risk of recurrent disease and reduced overall survival compared with those of patients with low hs-CRP. In conclusion, the present study demonstrated that hs-CRP was a prognostic factor for overall mortality and progression-free survival in patients with localised sarcoma at the time of diagnosis. Further studies are required to investigate the mechanism behind the association between hs-CRP and sarcoma prognosis and its potential use in clinical practice.

Macrophage Biomarkers sCD163 and sSIRPα in Serum Predict Mortality in Sarcoma Patients

Most soft tissue sarcoma (STS) patients do not respond to traditional checkpoint inhibitor treatment, which may be due to infiltrating immunosuppressive tumour-associated macrophages. This study investigated the prognostic value of four serum macrophage biomarkers. Methods: Blood samples were taken from 152 patients with STS at the time of diagnosis; clinical data were prospectively collected. The concentrations of four macrophage biomarkers (sCD163, sCD206, sSIRPα, sLILRB1) were measured in serum, dichotomised based on median concentration, and evaluated either individually or when combined with established prognostic markers. Results: All macrophage biomarkers were prognostic of overall survival (OS). However, only sCD163 and sSIRPα were prognostic for recurrent disease (sCD163: hazard ratio (HR): 1.97 (95% CI: 1.10-3.51) and sSIRPα: HR: 2.09 (95% CI: 1.16-3.77)). A prognostic profile was made based on sCD163 and sSIRPα; it also included c-reactive protein and tumour grade. Patients with intermediate- or high-risk prognostic profiles (adjusted for age and tumour size) had a higher risk of recurrent disease compared to low-risk patients (HR: 2.64 (95% CI: 0.97-7.19)) and (HR 4.3 (95% CI: 1.62-11.47)), respectively. Conclusion: This study demonstrated that serum biomarkers of immunosuppressive macrophages were prognostic for OS; when combined with well-established markers of recurrence they allowed for a clinically relevant categorising of patients.

Clinical benefit of neoadjuvant anti-PD-1/PD-L1 utilization among different tumors

PD‐1/PD‐L1 (programmed cell death‐1 and programmed death‐ligand 1) inhibitors utilization in neoadjuvant therapy has been assessed in tumors. This study focused on the clinical benefits of neoadjuvant anti‐PD‐1/PD‐L1 therapy. A comprehensive search was conducted in electronic databases to identify eligible studies. Major response rate (MRR) and complete response rate (CRR) were pooled in this analysis to assess the efficacy of neoadjuvant anti‐PD‐1/PD‐L1 utilization, all grades and high‐grade adverse events (AEs) were pooled to evaluate its safety. Twenty studies were included in this meta‐analysis, with 828 patients suffering from different tumors. The pooled CRR of triple‐negative breast cancer was 0.569 (95% CI 0.514, 0.624, I² = 0%) and the pooled MRR of lung cancer was 0.471 (95% CI 0.267, 0.575, I² = 0%). The most frequent adverse event was fatigue (0.272 95% CI 0.171, 0.402, I² = 87%), and the most common high‐grade adverse event was febrile neutropenia (0.084 95% CI 0.063, 0.112, I² = 85%). In conclusion, neoadjuvant anti‐PD‐1/PD‐L1 therapy received satisfactory clinical results in these tumors included.

A Systematic Review of the Tumor-Infiltrating CD8+ T-Cells/PD-L1 Axis in High-Grade Glial Tumors: Toward Personalized Immuno-Oncology

Based on preclinical findings, programmed death-ligand 1 (PD-L1) can substantially attenuate CD8⁺ T-cell-mediated anti-tumoral immune responses. However, clinical studies have reported controversial results regarding the significance of the tumor-infiltrating CD8⁺ T-cells/PD-L1 axis on the clinical picture and the response rate of patients with high-grade glial tumors to anti-cancer therapies. Herein, we conducted a systematic review according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statements to clarify the clinical significance of the tumor-infiltrating CD8⁺ T-cells/PD-L1 axis and elucidate the impact of this axis on the response rate of affected patients to anti-cancer therapies. Indeed, a better understanding of the impact of this axis on the response rate of affected patients to anti-cancer therapies can provide valuable insights to address the futile response rate of immune checkpoint inhibitors in patients with high-grade glial tumors. For this purpose, we systematically searched Scopus, Web of Science, Embase, and PubMed to obtain peer-reviewed studies published before 1 January 2021. We have observed that PD-L1 overexpression can be associated with the inferior prognosis of glioblastoma patients who have not been exposed to chemo-radiotherapy. Besides, exposure to anti-cancer therapies, e.g., chemo-radiotherapy, can up-regulate inhibitory immune checkpoint molecules in tumor-infiltrating CD8⁺ T-cells. Therefore, unlike unexposed patients, increased tumor-infiltrating CD8⁺ T-cells in anti-cancer therapy-exposed tumoral tissues can be associated with the inferior prognosis of affected patients. Because various inhibitory immune checkpoints can regulate anti-tumoral immune responses, the single-cell sequencing of the cells residing in the tumor microenvironment can provide valuable insights into the expression patterns of inhibitory immune checkpoints in the tumor micromovement. Thus, administrating immune checkpoint inhibitors based on the data from the single-cell sequencing of these cells can increase patients’ response rates, decrease the risk of immune-related adverse events development, prevent immune-resistance development, and reduce the risk of tumor recurrence.

Identification of Immune Function-Related Subtypes in Cutaneous Melanoma

Tumour immunotherapy combined with molecular typing is a new therapy to help select patients. However, molecular typing algorithms related to tumour immune function have not been thoroughly explored. We herein proposed a single sample immune signature network (SING) method to identify new immune function-related subtypes of cutaneous melanoma of the skin. A sample-specific network and tumour microenvironment were constructed based on the immune annotation of cutaneous melanoma samples. Then, the differences and heterogeneity of immune function among different subtypes were analysed and verified. A total of 327 cases of cutaneous melanoma were divided into normal and immune classes; the immune class had more immune enrichment characteristics. After further subdividing the 327 cases into three immune-related subtypes, the degree of immune enrichment in the "high immune subtype" was greater than that in other subtypes. Similar results were validated in both tumour samples and cell lines. Sample-specific networks and the tumour microenvironment based on immune annotation contribute to the mining of cutaneous melanoma immune function-related subtypes. Mutations in B2M and PTEN are considered potential therapeutic targets that can improve the immune response. Patients with a high immune subtype can generally obtain a better immune prognosis effect, and the prognosis may be improved when combined with TGF-β inhibitors.

Network Meta-analysis Comparing Efficacy, Safety and Tolerability of Anti-PD-1/PD-L1 Antibodies in Solid Cancers

Background: Multiple anti-PD-1/PD-L1 antibodies have been approved, and in some diseases, there is a choice of more than one. Comparative efficacy, safety and tolerability are unknown.

Methods: Randomized trials (RCTs) supporting the registration of single agent anti-PD1 or anti-PDL1 inhibitors between 2015-2019 were identified. We extracted the hazard ratio (HR) for overall survival (OS) and calculated the odds ratio (OR) for commonly reported safety and tolerability outcomes. We then performed a network meta-analysis, reporting multiple pair-wise comparisons between different anti-PD-1/PD-L1 antibodies.

Results: Sixteen RCTs comprising 10673 patients were included; 10 in non-small-cell lung cancer, 2 in melanoma, 2 in head and neck squamous cell carcinoma and 2 in urothelial cancer. Compared to pembrolizumab, efficacy was similar for nivolumab (HR: 1.02 95% CI: 0.91-1.14) and for atezolizumab (HR: 0.97 95% CI: 0.85-1.10), however, avelumab appeared inferior (HR: 1.30, 95% CI: 1.06-1.56). Pembrolizumab showed similar odds of serious adverse events (SAEs) as nivolumab (OR: 1.12, 95% CI: 0.56-2.27) and atezolizumab (OR: 1.05, 95% CI: 0.55-2.04). Compared to nivolumab, atezolizumab was associated with more SAEs (OR: 2.14, 95% CI: 1.47-3.12). Avelumab had the lowest odds of grade 3-4 adverse events compared to pembrolizumab (OR: 0.42, 95% CI: 0.24-0.74), nivolumab (OR: 0.38, 95% CI: 0.24-0.62) and atezolizumab (OR: 0.21, 95% CI: 0.14-0.33). The odds of treatment discontinuation without progression were similar between nivolumab and atezolizumab (OR: 1.20, 95% CI: 0.73-2.00), and between pembrolizumab and nivolumab (OR: 1.35, 95% CI: 0.83-2.17), but was higher with atezolizumab compared to nivolumab (OR: 2.56, 95% CI: 1.29-5.00). Pembrolizumab was associated with higher OR of immune-related adverse events (IRAEs) compared to nivolumab (OR: 2.12, 95% CI: 1.49-3.03) and atezolizumab (OR: 1.63, 95% CI: 1.09-2.43).

Conclusions: Pembrolizumab, nivolumab, and atezolizumab have similar efficacy. Avelumab appears less efficacious. Safety and tolerability seem better with avelumab, but worse with atezolizumab and pembrolizumab.

Prognostic value of lactate dehydrogenase for melanoma patients receiving anti-PD-1/PD-L1 therapy: A meta-analysis

BACKGROUND

Several studies indicate the level of pretreatment lactate dehydrogenase (LDH) may be associated with the prognosis of patients receiving immune checkpoint inhibitors targeting programmed death receptor-1 (PD-1)/programmed death ligand 1 (PD-L1) which had been reported to dramatically improve the survival of patients with advanced or metastatic melanoma; however, no consensus has been reached because the presence of controversial conclusions. This study was to perform a meta-analysis to comprehensively explore the prognostic values of LDH for melanoma patients receiving anti-PD1/PD-L1 monotherapy.

METHODS

A systematic electronic search in the databases of PubMed, EMBASE and the Cochrane library was performed to identify all related articles up to April, 2020. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were obtained to assess the prognostic values of pretreatment LDH in blood for overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 22 eligible studies involving 2745 patients were included. Of them, 19 studies with 20 results assessed the OS and the pooled analysis showed that an elevated pretreatment LDH level was significantly associated with a worse OS (HR = 2.44; 95% CI: 1.95-3.04, P < .001). Thirteen studies reported PFS and meta-analysis also revealed that a higher pretreatment LDH level predicted a significantly shorter PFS (HR, 1.61; 95% CI, 1.34-1.92; P < .001). Although heterogeneity existed among these studies, the same results were acquired in subgroup analyses based on sample size, country, study design, cut-off of LDH, type of PD-1/PD-L1 inhibitors and statistics for HRs (all HRs > 1 and P < .05).

CONCLUSION

This meta-analysis suggests LDH may serve as a potential biomarker to identify patients who can benefit from anti-PD-1/PD-L1 and then schedule treatments.

From Melanoma Development to RNA-Modified Dendritic Cell Vaccines: Highlighting the Lessons From the Past

Although melanoma remains the deadliest skin cancer, the current treatment has not resulted in the desired outcomes. Unlike chemotherapy, immunotherapy has provided more tolerable approaches and revolutionized cancer therapy. Although dendritic cell-based vaccines have minor side effects, the undesirable response rates of traditional approaches have posed questions about their clinical translation. The immunosuppressive tumor microenvironment can be the underlying reason for their low response rates. Immune checkpoints and indoleamine 2,3-dioxygenase have been implicated in the induction of immunosuppressive tumor microenvironment. Growing evidence indicates that the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase/Protein kinase B (PKB) (PI3K/AKT) pathways, as the main oncogenic pathways of melanoma, can upregulate the tumoral immune checkpoints, like programmed death-ligand 1. This study briefly represents the main oncogenic pathways of melanoma and highlights the cross-talk between these oncogenic pathways with indoleamine 2,3-dioxygenase, tumoral immune checkpoints, and myeloid-derived suppressor cells. Moreover, this study sheds light on a novel tumor antigen on melanoma, which has substantial roles in tumoral immune checkpoints expression, indoleamine 2,3-dioxygenase secretion, and stimulating the oncogenic pathways. Finally, this review collects the lessons from the previous unsuccessful trials and integrates their lessons with new approaches in RNA-modified dendritic cell vaccines. Unlike traditional approaches, the advances in single-cell RNA-sequencing techniques and RNA-modified dendritic cell vaccines along with combined therapy of the immune checkpoint inhibitors, indoleamine 2,3-dioxygenase inhibitor, and RNA-modified dendritic cell-based vaccine can overcome these auto-inductive loops and pave the way for developing robust dendritic cell-based vaccines with the most favorable response rate and the least side effects.

Adverse cardiac events in the treatment of non-small cell lung cancer with programmed death-1and programmed death-ligand 1 inhibitors: A protocol for systematic review and meta-analysis

BACKGROUND

Programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) inhibitors are immune therapies that have shown great promise in the treatment of multiple cancers. However, immune-related adverse events of PD-1 and PD-L1 inhibitors may limit their use in non-small cell lung cancer (NSCLC). Given the rising number of clinical trials in recent years, it is essential to perform a meta-analysis to provide assess the cardiotoxicity of PD-1/ PD-L1 inhibitors in NSCLC therapy.

METHOD AND ANALYSIS

The ClinicalTrials.gov, Embase, PubMed, and Cochrane Central Register of Controlled Trials repositories will be searched from their inception to December 2019. The bibliography of the searching process will be imported into Endnote X9 software. Two reviewers independently will screen the literature, extract data, and conduct the risk of bias for every added study. The data analysis will be analyzed using Stata15.0 software. Specific adverse cardiac events will be identified, with particular attention on atrial fibrillation, cardiac arrest, cardiac failure, and pericarditis. This review will be performed as per the Preferred Reporting Item for Systematic Review and meta-analysis statement recommendations.

ETHICS AND DISSEMINATION

This study will provide support for the cardiotoxicity linked to the treatment of NSCLC using PD-1/PD-L1 inhibitors. The data in the meta-analysis will be retrieved from completed and published clinical trials; therefore, ethical review and patient informed consent will not be required.

PROSPERO NUMBER

CRD42020156397.

A comparative view on the expression patterns of PD-L1 and PD-1 in soft tissue sarcomas

Soft tissue sarcomas (STSs) are heterogeneous cancers associated with poor prognosis due to high rates of local recurrence and metastasis. The programmed death receptor ligand 1 (PD-L1) is expressed in several cancers. PD-L1 interacts with its receptor, PD-1, on the surface of tumor-infiltrating lymphocytes (TILs), thereby attenuating anti-cancer immune response. Immune checkpoint inhibitors targeting this interaction have been established as effective anti-cancer drugs. However, studies on the PD-L1 and PD-1 expression status in STS are commonly limited by small sample size, analysis of single STS subtypes, or lack of combinatorial marker assessment. To overcome these limitations, we evaluated the expression patterns of intratumoral PD-L1, the number of TILs, their PD-1 expression, and associations with clinicopathological parameters in a large and comprehensive cohort of 225 samples comprising six STS subtypes. We found that nearly all STS subtypes showed PD-L1 expression on the tumor cells, albeit with a broad range of positivity across subtypes (50% angiosarcomas to 3% synovial sarcomas). Co-expression and correlation analyses uncovered that PD-L1 expression was associated with more PD-1-positive TILs (P < 0.001), higher tumor grading (P = 0.016), and worse patients' 5-year overall survival (P = 0.028). The results were in line with several publications on single STS subtypes, especially when comparing findings for STS with low and high mutational burden. In sum, the substantial portion of PD-L1 positivity, the co-occurrence of PD-1-positive TILs, and the association of PD-L1 with unfavorable clinical outcome provide rationales for immune checkpoint inhibition in patients with PD-L1-positive STS.

Efficacy and safety profiles of programmed cell death-1/programmed cell death ligand-1 inhibitors in the treatment of triple-negative breast cancer: A comprehensive systematic review

Triple-negative breast cancer (TNBC) is associated with worse prognosis, with limited treatment regiments available and higher mortality rate. Immune checkpoint inhibitors targeting programmed cell death-1 (PD-1) or programmed cell death-ligand 1 (PD-L1) showed great potentials in treating malignancies and may serve as potential therapies for TNBC. This systematic review aims to evaluate the efficacy and safety profiles of PD-1/PD-L1 inhibitors in the treatment of TNBC. Literature search was performed via PubMed, EBSCOhost, Scopus, and CENTRAL databases, selecting studies which evaluated the use of anti-PD-1/PDL1 for TNBC from inception until February 2019. Risk of bias was assessed by the Newcastle-Ottawa Scale (NOS). Overall, 7 studies evaluating outcomes of 1395 patients with TNBC were included in this systematic review. Anti-PD-1/PD-L1 showed significant antitumor effect, proven by their promising response (objective response rate (ORR), 18.5-39.4%) and survival rates (median overall survival (OS), 9.2-21.3 months). Moreover, anti- PD-1/PD-L1 yielded better outcomes when given as first-line therapy, and overexpression of PD-L1 in tumors showed better therapeutic effects. On the other hands, safety profiles were similar across agents and generally acceptable, with grade ≥3 treatment- related adverse effects (AEs) ranging from 9.5% to 15.6% and no new AEs were experienced by TNBC patients. Most grade ≥3 AEs are immune-mediated, which are manifested as neutropenia, fatigue, peripheral neuropathy, and anemia. PD-1/PD-L1 inhibitors showed promising efficacy and tolerable AEs, and thus may benefit TNBC patients. Further studies of randomized controlled trials with larger populations are needed to better confirm the potential of these agents.

Prognostic Implications of PD-L1 Expression in Breast Cancer: Systematic Review and Meta-analysis of Immunohistochemistry and Pooled Analysis of Transcriptomic Data

PURPOSE

Conflicting data have been reported on the prognostic value of PD-L1 protein and gene expression in breast cancer.Experimental Design: Medline, Embase, Cochrane Library, and Web of Science Core Collection were searched, and data were extracted independently by two researchers. Outcomes included pooled PD-L1 protein positivity in tumor cells, immune cells, or both, per subtype and per antibody used, and its prognostic value for disease-free and overall survival. A pooled gene expression analysis of 39 publicly available transcriptomic datasets was also performed.

RESULTS

Of the initial 4,184 entries, 38 retrospective studies fulfilled the predefined inclusion criteria. The overall pooled PD-L1 protein positivity rate was 24% (95% CI, 15%-33%) in tumor cells and 33% (95% CI, 14%- 56%) in immune cells. PD-L1 protein expression in tumor cells was prognostic for shorter overall survival (HR, 1.63; 95% CI, 1.07-2.46; P = 0.02); there was significant heterogeneity (I² = 80%, P _{heterogeneity} < 0.001). In addition, higher PD-L1 gene expression predicted better survival in multivariate analysis in the entire population (HR, 0.82; 95% CI, 0.74-0.90; P < 0.001 for OS) and in basal-like tumors (HR, 0.64; 95% CI, 0.52-0.80; P < 0.001 for OS; P _interaction 0.005).

CONCLUSIONS

The largest to our knowledge meta-analysis on the subject informs on PD-L1 protein positivity rates and its prognostic value in breast cancer. Standardization is needed prior to routine implementation. PD-L1 gene expression is a promising prognostic factor, especially in basal-like breast cancer. Discrepant prognostic information might be related to PD-L1 gene expression in the stroma.