Looking for the Optimal PD-1/PD-L1 Inhibitor in Cancer Treatment: A Comparison in Basic Structure, Function, and Clinical Practice

PD-L1 has a heterogeneous and dynamic expression in gastric cancer with implications for immunoPET

Introduction

This study aimed to investigate the dynamics of programmed death-ligand 1 (PD-L1) expression, spatial heterogeneity, and binding affinity of FDA-approved anti-PD-L1 antibodies (avelumab and atezolizumab) in gastric cancer. Additionally, we determined how PD-L1 glycosylation impacts antibody accumulation in gastric cancer cells.

Methods

Dynamic PD-L1 expression was examined in NCIN87 gastric cancer cells. Comparative binding studies of avelumab and atezolizumab were conducted in gastric cancer models, both in vitro and in vivo. Antibody uptake in tumors was visualized through positron emission tomography (PET) imaging. PD-L1 glycosylation status was determined via Western blot analyses before and after PNGase F treatment.

Results

Consistent findings revealed time-dependent PD-L1 induction in NCIN87 gastric cancer cells and spatial heterogeneity in tumors, as shown by PET imaging and immunofluorescence. Avelumab displayed superior binding affinity to NCIN87 cells compared to atezolizumab, confirmed by in vivo PET imaging and ex vivo biodistribution analyses. Notably, PD-L1 glycosylation at approximately 50 kDa was observed, with PNGase F treatment inducing a shift to 35 kDa in molecular weight. Tissue samples from patient-derived xenografts (PDXs) validated the presence of both glycosylated and deglycosylated PD-L1 (degPD-L1) forms in gastric cancer. Immunofluorescence microscopy and binding assays demonstrated enhanced avelumab binding post-deglycosylation.

Discussion

This study provides an understanding of dynamic and spatially heterogeneous PD-L1 expression in gastric cancer. Anti-PD-L1 immunoPET was able to visualize gastric tumors, and PD-L1 glycosylation has significant implications for antibody recognition. These insights contribute to demonstrating the complexities of PD-L1 in gastric cancer, holding relevance for refining PD-L1 imaging-based approaches.

Chimeric antigen receptor-immune cells against solid tumors: Structures, mechanisms, recent advances, and future developments

ABSTRACT

The advent of chimeric antigen receptor (CAR)-T cell immunotherapies has led to breakthroughs in the treatment of hematological malignancies. However, their success in treating solid tumors has been limited. CAR-natural killer (NK) cells have several advantages over CAR-T cells because NK cells can be made from pre-existing cell lines or allogeneic NK cells with a mismatched major histocompatibility complex (MHC), which means they are more likely to become an "off-the-shelf" product. Moreover, they can kill cancer cells via CAR-dependent/independent pathways and have limited toxicity. Macrophages are the most malleable immune cells in the body. These cells can efficiently infiltrate into tumors and are present in large numbers in tumor microenvironments (TMEs). Importantly, CAR-macrophages (CAR-Ms) have recently yielded exciting preclinical results in several solid tumors. Nevertheless, CAR-T, CAR-NK, and CAR-M all have their own advantages and limitations. In this review, we systematically discuss the current status, progress, and the major hurdles of CAR-T cells, CAR-NK cells, and CAR-M as they relate to five aspects: CAR structure, therapeutic mechanisms, the latest research progress, current challenges and solutions, and comparison according to the existing research in order to provide a reasonable option for treating solid tumors in the future.

Efficacy of immune checkpoint inhibitors combinations as first-line systemic treatment in patients with advanced urothelial carcinoma: A systematic review and network meta-analysis

BACKGROUND

Combinations of immune checkpoint inhibitors (ICI) with platinum-based chemotherapy (PlatinumCT) or with another ICI in the first-line setting for patients with metastatic urothelial carcinoma (mUC) have mixed results.

METHODS

Records were searched electronically from January 2019 to January 2024. A meta-analysis was performed to evaluate OS, progression-free survival (PFS), and overall response rate (ORR).

RESULTS

Immune-based combinations were associated with an OS (HR: 0.75; 95% CI: 0.61-0.92; p < 0.001; I2= 84.1%) and PFS benefit in the intention-to-treat population (HR: 0.67; 95%CI: 0.51-0.89; p < 0.001; I2 = 89.7%). There was no ORR improvement with immune-based combinations (HR: 1.36; 95% CI:0.84-2.20; p < 0.001; I2 = 92.6%).

CONCLUSION

This systematic review and study-level meta-analysis demonstrated that the immune-based combinations in first-line treatment for patients with mUC are associated with survival benefit.

The Development and Characterization of a Next-Generation Oncolytic Virus Armed with an Anti-PD-1 sdAb for Osteosarcoma Treatment In Vitro

Osteosarcoma (OS) is a primary bone malignancy characterized by an aggressive nature, limited treatment options, low survival rate, and poor patient prognosis. Conditionally replicative adenoviruses (CRAds) armed with immune checkpoint inhibitors hold great potential for enhanced therapeutic efficacy. The present study aims to investigate the anti-tumor efficacy of CAV2-AU-M2, a CAV2-based CRAd armed with an anti-PD-1 single-domain antibody (sdAb), against OS cell lines in vitro. The infection, conditional replication, cytopathic effects, and cytotoxicity of CAV2-AU-M2 were tested in four different OS cell lines in two-dimensional (2D) and three-dimensional (3D) cell cultures. CAV2-AU-M2 showed selective replication in the OS cells and induced efficient tumor cell lysis and death. Moreover, CAV2-AU-M2 produced an anti-PD-1 sdAb that demonstrated effective binding to the PD-1 receptors. This study demonstrated the first CRAd armed with an anti-PD-1 sdAb. This combined approach of two distinct immunotherapies is intended to enhance the anti-tumor immune response in the tumor microenvironment.

ARID2 mutations may relay a distinct subset of cutaneous melanoma patients with different outcomes

ARID genes encode subunits of SWI/SNF chromatin remodeling complexes and are frequently mutated in human cancers. We investigated the correlation between ARID mutations, molecular features, and clinical outcomes in melanoma patients. Cutaneous melanoma samples (n = 1577) were analyzed by next-generation sequencing. Samples were stratified by pathogenic/likely pathogenic mutation in ARID genes (ARID1A/2/1B/5B). PD-L1 expression was assessed using IHC (SP142; positive (+): ≥ 1%). Tumor mutation burden (TMB)-high was defined as ≥ 10 mutations/Mb. Transcriptomic signatures predictive of response to immune checkpoint inhibitors-interferon gamma and T-cell inflamed score were calculated. Real-world overall survival (OS) information was obtained from insurance claims data, with Kaplan-Meier estimates calculated from time of tissue collection until last date of contact. Mann-Whitney U, Chi-square, and Fisher exact tests were applied where appropriate, with p values adjusted for multiple comparisons. ARID2 mutations were more prevalent in cutaneous melanoma compared to ARID1A (11.0%: n = 451 vs 2.8%: n = 113), with concurrent ARID1A/ARID2 mutation in 1.1% (n = 46) of samples. ARID mutations were associated with a high prevalence of RAS pathway mutations-NF1 (ARID1A, 52.6%; ARID2, 48.5%; ARID1A/2, 63.6%; and ARID-WT, 13.3%; p < 0.0001) and KRAS (ARID1A, 3.5%; ARID2, 3.1%; ARID1A/2, 6.5%; and ARID-WT, 1.0%; p = 0.018)), although BRAF mutations were less common in ARID-mutated cohorts (ARID1A, 31.9%; ARID2, 35.6%; ARID1A/2, 26.1%; and ARID-WT, 50.4%; p < 0.0001). TMB-high was more common in ARID-mutated samples (ARID1A, 80.9%; ARID2, 89.9%; ARID1A/2, 100%; and ARID-WT, 49.4%; p < 0.0001), while PD-L1 positivity was similar across subgroups (ARID1A, 43.8%; ARID2, 51.1%; ARID1A/2, 52.5%; and ARID-WT, 44.9%; p = 0.109). Patients with ARID1A mutations had a higher prevalence of dMMR/MSI-H compared to those with ARID-WT (2.7% vs 0.2%, p = 0.030). Median IFN-γ and T-cell signatures were higher in ARID2-mutated samples compared to ARID-WT (IFN-γ: - 0.15 vs - 0.21, p = 0.0066; T-cell: 23.5 vs - 18.5, p = 0.041). ARID2-mutated patients had improved survival compared to ARID-WT; (HR: 1.22 (95% CI 1.0-1.5), p = 0.022). No additional OS benefit was observed with anti-PD-1 therapy for ARID2 mutation compared to ARID-WT. Melanoma patients with ARID mutations exhibited higher prevalence of markers associated with ICI response, including TMB-H, and immune-related signatures. Our data also suggests improved survival outcome in patients with ARID2 mutations, irrespective of anti-PD1 therapy.

Treatment-emergent antidrug antibodies related to PD-1, PD-L1, or CTLA-4 inhibitors across tumor types: a systematic review

BACKGROUND

Increased understanding of how the immune system regulates tumor growth has innovated the use of immunotherapeutics to treat various cancers. The impact of such therapies, including programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, on the production of antidrug antibodies (ADAs) and their impact on outcomes, is poorly understood. This study aims to evaluate the clinical trial evidence on ADA incidence associated with PD-1, PD-L1, and CTLA-4 inhibitors in the treatment of cancer and to assess associations between treatment administered, ADA incidence, and treatment outcomes.

METHODS

Embase®, Medline®, and EBM Reviews were searched via the OVID® platform on February 15, 2022. Conference proceedings, clinical trial registries, and global regulatory and reimbursement body websites were also searched. Eligible publications included clinical trials enrolling patients receiving cancer treatment with either PD-1, PD-L1, or CTLA-4 reporting outcomes including incidence or prevalence of ADAs and the impact of immunogenicity on treatment safety and efficacy. Reference lists of eligible publications were also searched. The review was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and evidence quality assessment was conducted using the appropriate Joanna Briggs Institute Critical Appraisal tool.

RESULTS

After screening 4160 records and reviewing 97 full publications, a total of 34 publications reporting on 68 trials were included. A further 41 relevant clinical trials were identified on ClinicalTrials.gov and a further 32 from searches of packaging inserts. In total, 141 relevant trials covering 15 different checkpoint inhibitors and 16 different tumor types were included. Across the included trials, atezolizumab was associated with the highest incidence of ADAs (29.6% of 639 patients), followed by nivolumab (11.2% of 2,085 patients). Combination checkpoint inhibitor treatment appeared to increase the rate of ADAs versus monotherapy. Only 17 trials reported on the impact of ADAs on treatment outcomes with mixed results for the impact of ADAs on treatment efficacy, safety, and pharmacokinetics.

CONCLUSIONS

Checkpoint inhibitors for the treatment of cancer are immunogenic, with the incidence of treatment-emergent ADAs varying between individual therapies. It remains unclear what impact ADAs have on treatment outcomes.

Engagement of CD300c by a novel monoclonal antibody induces the differentiation of monocytes to M1 macrophages

Human CD300c is expressed on various immune or cancer cells and is a novel B7 family member, functioning as an activity modulator on immune cells. To elucidate the function of CD300c, we developed CL7, a human CD300c-specific monoclonal antibody, and assessed its biological activity. The specific binding of CL7 monoclonal antibody against recombinant CD300c antigen was confirmed using enzyme-linked immunosorbent assay and surface plasmon resonance analysis. The binding affinity of CL7 was strong at the sub-nanomolar level. Furthermore, CL7 effectively bound to exogenously expressed CD300c on 293T cells. CL7 antibody differentiated monocytes to M1 macrophages, as evidenced by the upregulated expression of M1-specific cell surface markers and increased secretion of M1-specific cytokines in vitro in THP-1 cells and primary macrophages, as well as the increased population size of M1 macrophages in tumors grafted into mice. Additionally, CL7 treatment upregulated PD-L1 expression on THP-1 cells. We confirmed that the mechanism of M1 macrophage differentiation was through the mitogen-activated protein kinase and NF-κB signaling pathways. CD300c expression on various immune and cancer cells was similar to that of the well-known immune checkpoint PD-L1, suggesting the possibility of CD300c as a novel tumor biomarker. We also confirmed that the tumor size was substantially reduced by CL7 antibody treatment in the CT26 mouse model. Our study supports that CD300c is a potential therapeutic target in immuno-oncology. Overall, the CD300c-specific monoclonal antibody, CL7, is a promising immunotherapeutic agent, and it induces enhanced differentiation of M1 macrophages and/or their infiltration into the tumor microenvironment.

PD-1 and PD-L1: architects of immune symphony and immunotherapy breakthroughs in cancer treatment

PD-1 (Programmed Cell Death Protein-1) and PD-L1 (Programmed Cell Death Ligand-1) play a crucial role in regulating the immune system and preventing autoimmunity. Cancer cells can manipulate this system, allowing them to escape immune detection and promote tumor growth. Therapies targeting the PD-1/PD-L1 pathway have transformed cancer treatment and have demonstrated significant effectiveness against various cancer types. This study delves into the structure and signaling dynamics of PD-1 and its ligands PD-L1/PD-L2, the diverse PD-1/PD-L1 inhibitors and their efficacy, and the resistance observed in some patients. Furthermore, this study explored the challenges associated with the PD-1/PD-L1 inhibitor treatment approach. Recent advancements in the combination of immunotherapy with chemotherapy, radiation, and surgical procedures to enhance patient outcomes have also been highlighted. Overall, this study offers an in-depth overview of the significance of PD-1/PD-L1 in cancer immunotherapy and its future implications in oncology.

Hsa-LINC02418/mmu-4930573I07Rik regulated by METTL3 dictates anti-PD-L1 immunotherapeutic efficacy via enhancement of Trim21-mediated PD-L1 ubiquitination

BACKGROUND

Limited response to programmed death ligand-1 (PD-L1)/programmed death 1 (PD-1) immunotherapy is a major hindrance of checkpoint immunotherapy in non-small cell lung cancer (NSCLC). The abundance of PD-L1 on the tumor cell surface is crucial for the responsiveness of PD-1/PD-L1 immunotherapy. However, the negative control of PD-L1 expression and the physiological significance of the PD-L1 inhibition in NSCLC immunotherapy remain obscure.

METHODS

Bioinformatics analysis was performed to profile and investigate the long non-coding RNAs that negatively correlated with PD-L1 expression and positively correlated with CD8+T cell infiltration in NSCLC. Immunofluorescence, in vitro PD-1 binding assay, T cell-induced apoptosis assays and in vivo syngeneic mouse models were used to investigate the functional roles of LINC02418 and mmu-4930573I07Rik in regulating anti-PD-L1 therapeutic efficacy in NSCLC. The molecular mechanism of LINC02418-enhanced PD-L1 downregulation was explored by immunoprecipitation, RNA immunoprecipitation (RIP), and ubiquitination assays. RIP, luciferase reporter, and messenger RNA degradation assays were used to investigate the m6A modification of LINC02418 or mmu-4930573I07Rik expression. Bioinformatics analysis and immunohistochemistry (IHC) verification were performed to determine the significance of LINC02418, PD-L1 expression and CD8+T cell infiltration.

RESULTS

LINC02418 is a negative regulator of PD-L1 expression that positively correlated with CD8+T cell infiltration, predicting favorable clinical outcomes for patients with NSCLC. LINC02418 downregulates PD-L1 expression by enhancing PD-L1 ubiquitination mediated by E3 ligase Trim21. Both hsa-LINC02418 and mmu-4930573I07Rik (its homologous RNA in mice) regulate PD-L1 therapeutic efficacy in NSCLC via Trim21, inducing T cell-induced apoptosis in vitro and in vivo. Furthermore, METTL3 inhibition via N6-methyladenosine (m6A) modification mediated by YTHDF2 reader upregulates hsa-LINC02418 and mmu-4930573I07Rik. In patients with NSCLC, LINC02418 expression is inversely correlated with PD-L1 expression and positively correlated with CD8+T infiltration.

CONCLUSION

LINC02418 functions as a negative regulator of PD-L1 expression in NSCLC cells by promoting the degradation of PD-L1 through the ubiquitin-proteasome pathway. The expression of LINC02418 is regulated by METTL3/YTHDF2-mediated m6A modification. This study illuminates the underlying mechanisms of PD-L1 negative regulation and presents a promising target for improving the effectiveness of anti-PD-L1 therapy in NSCLC.

A CD276-Targeted Antibody-Drug Conjugate to Treat Non-Small Lung Cancer (NSCLC)

Non-small cell lung cancer (NSCLC) patients, accounting for approximately 85% of lung cancer cases, are usually diagnosed in advanced stages. Traditional surgical resection and radiotherapy have very limited clinical benefits. The objective of this study was to develop and evaluate a targeted therapy, antibody-drug conjugate (ADC), for NSCLC treatment. Specifically, the CD276 receptor was evaluated and confirmed as an ideal surface target of NSCLC in the immunohistochemistry (IHC) staining of seventy-three patient tumor microarrays and western blotting analysis of eight cell lines. Our anti-CD276 monoclonal antibody (mAb) with cross-activity to both human and mouse receptors showed high surface binding, effective drug delivery and tumor-specific targeting in flow cytometry, confocal microscopy, and in vivo imaging system analysis. The ADC constructed with our CD276 mAb and payload monomethyl auristatin F (MMAF) showed high anti-NSCLC cytotoxicity to multiple lines and effective anti-tumor efficacy in both immunocompromised and immunocompetent NSCLC xenograft mouse models. The brief mechanism study revealed the integration of cell proliferation inhibition and immune cell reactivation in tumor microenvironments. The toxicity study did not detect off-target immune toxicity or peripheral toxicity. Altogether, this study suggested that anti-CD276 ADC could be a promising candidate for NSCLC treatment.

Efficacy and safety of immunochemotherapy, immunotherapy, chemotherapy, and targeted therapy as first-line treatment for advanced and metastatic esophageal cancer: a systematic review and network meta-analysis

Background

The treatment of esophageal cancer has entered a new phase with the development of immunotherapy. The current investigation purpose is to investigate and contrast the efficacy and safety of immunotherapy, immunochemotherapy, chemotherapy, and targeted therapy as first-line treatment for individuals suffering from advanced and metastatic esophageal cancer.

Methods

Within the framework of this systematic review and network meta-analysis, clinical trials published or reported in English up until 01 May, 2022, were retrieved from Embase, PubMed, Cochrane Central Register of Controlled Trials, the ClinicalTrials.gov databases, ESMO, and ASCO. The analysis incorporated randomized controlled trials (RCTs) from phase 2 to 3 that evaluated a minimum of two first-line therapeutic regimens for metastatic esophageal cancer were included in the analysis. The primary outcomes were overall survival (OS) and progression-free survival (PFS). Secondary clinical outcomes included the incidence of objective response rate (ORR), and adverse events (AEs) of any grade and ≥3 grade. Relative summary data were extracted from included studies by GZ, HS, WS, and TD. For clear statistical analysis, chemotherapy was divided into two categories of fluorouracil-based chemotherapy (FbCT) and fluorouracil-free chemotherapy (FfCT). Bayesian frequentist approach was employed to conduct the network meta-analysis. The indirect intercomparison between regimens was presented with league tables (HRs and 95% CI for OS and PFS, ORs and 95% CI for ORR and AEs). A greater surface value under the cumulative ranking (SUCRA) indicates a higher potential ranking for the corresponding treatment. A further calculation of relative results about esophageal squamous cell cancer was performed in the subgroup analysis. The current protocol for the systematic review has been properly registered on PROSPERO (registration number: CRD42021241145).

Findings

The final analysis comprised 17 trials that involved 9128 patients and 19 distinct treatment regimens. Within the scope of investigated immunotherapy (IO) combinations, toripalimab + FfCT (tori + FfCT) demonstrated the best OS advantages (tori + FfCT vs. FbCT, HR 0.57, 95% CI 0.38-0.85; tori + FfCT vs. FfCT, HR 0.58, 95% CI 0.43-0.78). In terms of PFS, camrelizumab + FfCT (cam + FfCT) demonstrated the best PFS advantages (FbCT vs. cam + FfCT, HR 1.79, 95% CI 1.22-2.63; FfCT vs. cam + FfCT, HR 1.79, 95% CI 1.47-2.17). Nivolumab + FbCT (nivo + FbCT vs. FfCT, OR 3.29, 95% CI 1.43-7.56) showed the best objective responses. Compared to the conventional chemotherapy regimen, the toxicity was observed to be the slightest for the tori + FfCT (FbCT vs. tori + FfCT, OR 3.07, 95% CI 1.22-7.7) and sintilimab + FfCT (FbCT vs. sin + FfCT, OR 2.93, 95% CI 1.16-7.37). The results in this study were evaluated as having a low heterogeneity since the I² value was ≤25% in all analyses.

Interpretation

Compared to foreign IO combinations, sin + FfCT, tori + FfCT, cam + FfCT, and tisle + FbCT are superior first-line treatment options for patients with advanced and metastatic esophageal cancer. Although foreign IO combinations, such as pembro + FbCT and nivo + FbCT obtained better objective response rates than other IO combinations, the addition of chemotherapy to IO worsens the safety profiles. Our findings could provide complementary evidence for current guideline recommendations.

Funding

This work was supported by a grant from the Science and Technology Program of Guangzhou, China (202206010103); and Natural Science Foundation of Guangdong Province (2022A1515012469).

The effect of gender on the clinical outcome of PD-1/PD-L1 inhibitor in advanced lung cancer patients

BACKGROUND

Programmed death protein-1/ligand-1 (PD-1/L1) inhibitors have widely used in the treatment of lung cancer. Some literatures indicated that different gender might not have equal immune response, but no agreement have reached on the issue. Hence, we performed a systematic review and meta-analysis that examine the effect of gender on the clinical outcome of PD-1/PD-L1 inhibitor in advanced lung cancer patients.

METHODS

Related database and conferences were searched. Studies that reported the relationship between gender and the overall survival (OS) or progression-free survival (PFS) of PD-1/L1 inhibitor were included. Meta-analysis was conducted to obtain pooled hazard ratios (HRs) with 95% CI.

RESULTS

We included 34 studies with 11,883 lung cancer patients. Meta-analysis showed that PD-1/PD-L1 inhibitors significantly prolonged the OS (males: HR 0.71, 95%CI 0.66-0.77; females: HR 0.72, 95%CI 0.63-0.82) and PFS (males: HR 0.60, 95%CI 0.55-0.66; females: HR 0.72, 95%CI 0.62-0.84) versus chemotherapy. The clinical benefit (OS HR: 0.99; PFS HR: 0.83) was not statistically significant between males and females. In patients treated with cemiplimab, male patients had a better OS (0.53, 95%CI 0.42-0.66) and PFS (OS 1.51, 95%CI 0.80-2.82) compared with female patients, but the small number of female patients precludes us from drawing any firm conclusions in female subpopulations.

CONCLUSION

The clinical benefit of PD-1/PD-L1 inhibitors was not statistically significant between males and females during the treatment of lung cancer. In the future, researchers who are designing new immunotherapy studies should ensure a larger inclusion of women in trials, to avoid erroneously extending to women results that are obtained mainly in male patients.

Early low blood MALT1 expression levels forecast better efficacy of PD‑1 inhibitor‑based treatment in patients with metastatic colorectal cancer

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) modulates colorectal cancer (CRC) malignant behaviors and tumor immune escape. The present study aimed to explore the association of MALT1 with treatment response and survival time among patients with metastatic CRC (mCRC) after programmed cell death protein-1 (PD-1) inhibitor-based treatment. MALT1 from the blood samples of 75 patients with unresectable mCRC receiving PD-1 inhibitor-based treatment at baseline and after 2-cycle treatment, as well as 20 healthy controls (HCs), was detected by reverse transcription-quantitative PCR. In the patients with mCRC, the objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS) were calculated. MALT1 expression was elevated in patients with mCRC compared with that in HCs (P<0.001). In patients with mCRC, MALT1 expression was positively correlated with multiple (vs. single) metastasis (P=0.032) and peritoneum metastasis (P=0.029). MALT1 levels before treatment were decreased in ORR patients vs. non-ORR patients (P=0.043) and in DCR patients vs. non-DCR patients (P=0.007). Additionally, MALT1 expression was reduced after treatment compared with that before treatment (P<0.001). Meanwhile, MALT1 expression after treatment was notably decreased in ORR patients vs. non-ORR patients (P<0.001) and in DCR patients vs. non-DCR patients (P<0.001). Furthermore, a low MALT1 level before treatment was associated with longer PFS (P=0.030) and OS (P=0.025) times. Decreased MALT1 expression after treatment and a decline in MALT1 expression of >30% after treatment (ratio to MALT1 before treatment) (both P≤0.001) presented more significant associations with prolonged PFS and OS times. In conclusion, early low levels of blood MALT1 during therapy may predict an improved response to PD-1 inhibitor-based treatment and survival time in patients with mCRC.

Development of polyclonal heavy chain antibodies targeting programmed death ligand-1

Programmed death ligand-1 (PD-L1, CD274 and B7-H1) has been described as a ligand for immune inhibitory receptor programmed death protein 1 (PD-1). With binding to PD-1 on activated T cells, PD-L1 can prevent T cell responses via motivating apoptosis. Consequently, it causes cancers immune evasion and helps the tumor growth; hence, PD-L1 is regarded as a therapeutic target for malignant cancers. The anti-PD-L1 monoclonal antibody targeting PD-1/PD-L1 immune checkpoint has attained remarkable outcomes in clinical application and has turned to one of the most prevalent anti-cancer drugs. The present study aimed to develop polyclonal heavy chain antibodies targeting PD-L1via Camelus dromedarius immunization. The extra-cellular domain of human PD-L1 (hPD-L1) protein was cloned, expressed, and purified. Afterwards, this recombinant protein was utilized as an antigen for camel immunization to acquire polyclonal camelid sera versus this protein. Our outcomes showed that hPD-L1 protein was effectively expressed in the prokaryotic system. The antibody-based techniques, such as enzyme-linked immunosorbent assay, western blotting, and flow cytometry displayed that the hPD-L1 protein was detected by generated polyclonal antibody. Due to the advantages of multi-epitope-binding ability, our study exhibited that camelid antibody is effective to be applied significantly for detection of PD-L1 protein in essential antibody-based studies.

Immunotherapy Plus Radiotherapy for the Treatment of Sarcomas: Is There a Potential for Synergism?

Soft tissue sarcoma (STS) is a highly heterogeneous malignant tumor derived from mesenchymal tissue. Advanced STS has a poor response to the current anti-cancer therapeutic options, with a median overall survival of less than two years. Thus, new and more effective treatment methods for STS are needed. Increasing evidence has shown that immunotherapy and radiotherapy have synergistic therapeutic effects against malignant tumors. In addition, immunoradiotherapy has yielded positive results in clinical trials for various cancers. In this review, we discuss the synergistic mechanism of immunoradiotherapy in cancer treatment and the application of this combined regimen for the treatment of several cancers. In addition, we summarize the existing evidence on the use of immunoradiotherapy for the treatment of STS and the relevant clinical trials that are currently ongoing. Furthermore, we identify challenges in the use of immunoradiotherapy for the treatment of sarcomas and propose methods and precautions for overcoming these challenges. Lastly, we propose clinical research strategies and future research directions to help in the research and treatment of STS.

Engineering tumor-specific gene nanomedicine to recruit and activate T cells for enhanced immunotherapy

PD-1/PD-L1 blockade therapy that eliminates T-cell inhibition signals is successful, but poor benefits are often observed. Increasing T-cell infiltration and quantity of PD-1/PD-L1 inhibitors in tumor can improve efficacy but remains challenging. Here, we devise tumor-specific gene nanomedicines to mobilize tumor cells to secrete CXCL9 (T-cell chemokine) and anti-PD-L1 scFv (αPD-L1, PD-L1 blocking agent) for enhanced immunotherapy. The tyrosinase promoter-driven NP_Tyr-C9AP can specifically co-express CXCL9 and αPD-L1 in melanoma cells, thereby forming a CXCL9 gradient for T-cell recruitment and high intratumoral αPD-L1 concentration for enhancing T-cell activation. As a result, NP_Tyr-C9AP shows strong antimelanoma effects. Moreover, specific co-expression of CXCL9 and αPD-L1 in various tumor cells is achieved by replacing the tyrosinase promoter of NP_Tyr-C9AP with a survivin promoter, which increases T-cell infiltration and activation and therapeutic efficacy in multiple tumors in female mice. This study provides a strategy to maximize the immunotherapeutic outcome regardless of the heterogeneous tumor microenvironment.

Comprehensive characterization of ferroptosis in hepatocellular carcinoma revealing the association with prognosis and tumor immune microenvironment

Background

Ferroptosis is a type of regulatory cell death (RCD) mode that depends on iron-mediated oxidative damage. It has the potential to improve the efficacy of tumor immunotherapy by modulating the tumor microenvironment (TME). Currently, immunotherapy has significantly improved the overall treatment strategy for advanced hepatocellular carcinoma (HCC), but the distinct immune microenvironment and high tolerance to the immune make massive differences in the immunotherapy effect of HCC patients. As a result, it is imperative to classify HCC patients who may benefit from immune checkpoint therapy. Simultaneously, the predictive value of ferroptosis in HCC and its potential role in TME immune cell infiltration also need to be further clarified.

Methods

Three ferroptosis molecular models were built on the basis of mRNA expression profiles of ferroptosis-related genes (FRGs), with notable variations in immunocyte infiltration, biological function, and survival prediction. In order to further investigate the predictive impact of immunotherapy response in HCC patients, the ferroptosis score was constructed using the principal component analysis (PCA) algorithm to quantify the ferroptosis molecular models of individual tumors.

Results

In HCC, there were three totally different ferroptosis molecular models. The ferroptosis score can be used to assess genetic variation, immunotherapy response, TME characteristics, and prognosis. Notably, tumors with low ferroptosis scores have extensive tumor mutations and immune exhaustion, which are associated with a poor prognosis and enhanced immunotherapy response.

Conclusions

Our study indicates that ferroptosis plays an indispensable role in the regulation of the tumor immune microenvironment. For HCC, the ferroptosis score is an independent prognostic indicator. Assessing the molecular model of ferroptosis in individual tumors will assist us in better understanding the characteristics of TME, predicting the effect of immunotherapy in HCC patients, and thus guiding a more reasonable immunotherapy program.

Fast, Accurate, and System-Specific Variable-Resolution Modeling of Proteins

In recent years, a few multiple-resolution modeling strategies have been proposed, in which functionally relevant parts of a biomolecule are described with atomistic resolution, with the remainder of the system being concurrently treated using a coarse-grained model. In most cases, the parametrization of the latter requires lengthy reference all-atom simulations and/or the usage of off-shelf coarse-grained force fields, whose interactions have to be refined to fit the specific system under examination. Here, we overcome these limitations through a novel multiresolution modeling scheme for proteins, dubbed coarse-grained anisotropic network model for variable resolution simulations, or CANVAS. This scheme enables a user-defined modulation of the resolution level throughout the system structure; a fast parametrization of the potential without the necessity of reference simulations; and the straightforward usage of the model on the most commonly used molecular dynamics platforms. The method is presented and validated with two case studies, the enzyme adenylate kinase and the therapeutic antibody pembrolizumab, by comparing the results obtained with the CANVAS model against fully atomistic simulations. The modeling software, implemented in Python, is made freely available for the community on a collaborative github repository.

Advances in pharmacokinetics and pharmacodynamics of PD-1/PD-L1 inhibitors

Immune checkpoint inhibitors (ICIs) are a group of drugs designed to improve the therapeutic effects on various types of malignant tumors. Irrespective of monotherapy or combinational therapies as first-line and later-line therapy, ICIs have achieved benefits for various tumors. Programmed cell death protein-1 (PD-1) / ligand 1 (PD-L1) is an immune checkpoint that suppresses antitumor immunity, especially in the tumor microenvironment (TME). PD-1/PD-L1 immune checkpoint inhibitors block tumor-related downregulation of the immune system, thereby enhancing antitumor immunity. In comparison with traditional small-molecule drugs, ICIs exhibit pharmacokinetic characteristics owing to their high molecular weight. Furthermore, different types of ICIs exhibit different pharmacodynamic characteristics. Hence, ICIs have been approved for different indications by the Food and Drug Administration (FDA) and National Medical Products Administration (NMPA). This review summarizes pharmacokinetic and pharmacodynamic studies of PD-1/ PD-L1 inhibitors to provide a reference for rational clinical application.

The role of immune checkpoint inhibitors (ICI) as adjuvant treatment in renal cell carcinoma (RCC): A systematic review and meta-analysis

Pembrolizumab, a PD-1 ICI is approved for the adjuvant treatment of postnephrectomy patients with clear cell RCC in some countries worldwide. However, recent negative data from randomized clinical trials (RCT) with another ICIs makes the benefit of this treatment uncertain. A systematic review and study-level meta-analysis was performed to evaluate the benefit of disease-free survival (DFS) with adjuvant ICI treatment for patients with localized and/or metastatic resected RCC. Using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement, a systematic search was performed in PUBMED/MEDLINE, Scopus and EMBASE up to September 15, 2022. The statistical analysis was performed by ProMeta 3 software in intention-to-treat (ITT) population and in predetermined subgroups. Four RCT totalizing 3407 patients were included in this analysis. Systemic immunotherapy was pembrolizumab, atezolizumab, nivolumab, and ipilimumab plus nivolumab in 496, 390, 404, and 405 patients, respectively. In the ITT population there was a nonstatistically significant DFS benefit with adjuvant ICI (HR: 0.85, 95% CI: 0.69-1.04). Regarding the subgroups, there was a DFS benefit for PD-L1 positive (HR: 0.72; 95% CI: 0.55-0.94), intermediate-high risk patients (HR: 0.77; 95% CI: 0.63-0.94), and patients with sarcomatoid component (HR: 0.66; 95% CI: 0.43-0.99). This meta-analysis did not demonstrate a statistically significant DFS benefit in overall population, however considering the heterogeneity between the RCTs the use of adjuvant ICI should be individualized.

Effects of small molecule-induced dimerization on the programmed death ligand 1 protein life cycle

The programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) checkpoint blockade is central to Immuno-Oncology based therapies, and alternatives to antibody blockers of this interaction are an active area of research due to antibody related toxicities. Recently, small molecule compounds that induce PD-L1 dimerization and occlusion of PD-1 binding site have been identified and developed for clinical trials. This mechanism invokes an oligomeric state of PD-L1 not observed in cells previously, as PD-L1 is generally believed to function as a monomer. Therefore, understanding the cellular lifecycle of the induced PD-L1 dimer is of keen interest. Our report describes a moderate but consistent increase in the PD-L1 rate of degradation observed upon protein dimerization as compared to the monomer counterpart. This subtle change, while not resolved by measuring total PD-L1 cellular levels by western blotting, triggered investigations of the overall protein distribution across various cellular compartments. We show that PD-L1 dimerization does not lead to rapid internalization of neither transfected nor endogenously expressed protein forms. Instead, evidence is presented that dimerization results in retention of PD-L1 intracellularly, which concomitantly correlates with its reduction on the cell surface. Therefore, the obtained data for the first time points to the ability of small molecules to induce dimerization of the newly synthesized PD-L1 in addition to the protein already present on the plasma membrane. Overall, this work serves to improve our understanding of this important target on a molecular level in order to guide advances in drug development.

Tumor Suppression by PD-1/PD-L1 Interaction Blockage in Mice Model

Background

Overexpression of programmed cell death ligand 1 (PD-L1) in tumor cells and subsequent interaction with the programmed cell death protein 1 (PD-1) in tumor-infiltrating T cells cause an immune evasion of the tumor from cytotoxic T-cells. Therefore, inhibiting such interaction by a recombinant PD-1 can hinder tumor growth and extend the survival rate.

Methods

The mouse extracellular domain of PD-1 (mPD-1) was expressed in E. coli BL21 (DE3) strain and purified using nickel affinity chromatography. The binding ability of the purified protein to human PD-L1 was studied using ELISA. Finally, the tumor-bearing mice were used to evaluate the potential antitumor effect.

Results

The recombinant mPD-1 showed a significant binding capacity to human PD-L1 at the molecular level. The tumor size significantly decreased in the tumor-bearing mice after the intra-tumoral injections of mPD-1. Moreover, the survival rate increased significantly after eight weeks of monitoring. The histopathology revealed the necrosis in the tumor tissue of the control group compared to the mPD-1 received mice.

Conclusions

Our outcomes propose that interaction blockade between PD-1 and PD-L1 is a promising approach for targeted tumor therapy.

Cutaneous adverse events in patients treated with PD-1/PD-L1 checkpoint inhibitors and their association with survival: a systematic review and meta-analysis

Immune-related cutaneous adverse events (irCAEs) in patients treated with programmed cell death-1/programmed death-ligand 1 (PD-1/PD-L1) checkpoint inhibitors may be associated with better clinical outcomes. However, the extent to which these results can be extrapolated to all tumour types remains unclear. Herein, we conducted a meta-analysis of patients with cancer receiving anti-PD-1/PD-L1 immunotherapy, to determine the cumulative incidence of irCAEs and their association with survival. We systematically searched six databases (PubMed, Embase, Cochrane, CNKI, CSPD, and CQVIP database) for all cohort studies reporting the relationship between irCAEs and patient survival from the time of database construction to 1 November, 2020. The primary outcomes were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS), with complete remission (CR), partial remission (PR), stable disease (SD), and progressive disease (PD) as secondary outcomes. Patients with irCAEs exhibited higher ORR, and were more likely to report CR and PR and less likely to develop PD than those who did not experience irCAEs. Moreover, the occurrence of irCAEs was significantly associated with both favourable PFS and OS. Therefore, patients with irCAEs have better survival benefit and a significantly lower risk of tumour progression or death. Hence, the occurrence of irCAEs may be a useful marker for predicting the clinical efficacy of anti-PD-1/PD-L1 immunotherapy.

Real-World Comparative Effectiveness of Nivolumab versus Pembrolizumab in Patients with Unresectable Hepatocellular Carcinoma

PURPOSE

Immune checkpoint inhibitors are effective therapies for advanced hepatocellular carcinoma (HCC); however, comparisons of the clinical efficacy and safety profile for these drugs are still scarce. Thus, the aims of this study were to investigate the differences in efficacy and safety between nivolumab and pembrolizumab in unresectable HCC patients in a real-world setting.

PATIENTS AND METHODS

A total of 115 patients who received treatment with nivolumab (n = 73) or pembrolizumab (n = 42) in combination with or without tyrosine kinase inhibitors was enrolled. Therapeutic response, survival outcomes, and safety profiles were compared among these groups. Multivariate analysis of survival response was performed using Cox proportional hazards regression.

RESULTS

Patients treated with pembrolizumab demonstrated a significantly higher objective response rate than those with nivolumab (38.1% vs. 15.1%; odds ratio 4.18, p = 0.005) regardless of the combination strategies. In addition, pembrolizumab performed a better overall survival (OS) than nivolumab, (34.9 vs. 9.5 months; hazard ratio (HR) = 0.39, p = 0.004). In subgroup analysis, pembrolizumab exhibited favorable OS than nivolumab for monotherapy (HR = 0.16, p = 0.001) or combination therapy (HR = 0.33, p = 0.006) as second-line or later-line (HR = 0.19, p = 0.001) therapy and those with (HR = 0.31, p = 0.006) or without (HR = 0.15, p = 0.004) well-compensated liver disease. The incidence of adverse events was comparable for both treatments.

CONCLUSION

Both pembrolizumab and nivolumab had significant effects for HCC therapy, and pembrolizumab had a significant survival benefit as compared with nivolumab.

Tremelimumab and durvalumab in the treatment of unresectable, advanced hepatocellular carcinoma

Liver cancer is the third most common cause of cancer-related mortality worldwide, with over 780,000 deaths in 2018. About 90% of liver cancer cases are hepatocellular carcinoma (HCC), a prototype of inflammation-driven cancer, leading to a robust rationale for the exploration of immune therapy. Previously approved agents for first-line therapy, such as sorafenib, lenvatinib and bevacizumab combined with atezolizumab, have focused on angiogenesis. HIMALAYA was the first trial to demonstrate the benefit of dual immune checkpoint inhibitors, representing a new treatment option in this scenario.

Effect of proton pump inhibitors on the clinical outcomes of PD-1/PD-L1 inhibitor in solid cancer patients

BACKGROUND

Some concomitant drugs may affect the efficacy of programmed death protein-1/ ligand-1 (PD-1/L1) inhibitors. Among the various concomitant drugs, proton-pump inhibitors (PPI) have attracted some attention but have not reached a conclusion. We conducted a meta-analysis to evaluate the impact of PPIs on the survival of cancer patients treated with PD-1/L1 inhibitors.

MATERIAL/METHODS

Related databases and conferences reports were searched. Studies that reported the relationship between PPI use and clinical outcomes of PD-1/L1 inhibitors were included. Meta-analysis was conducted to obtain pooled hazard ratios (HR)s with 95% confidence interval (CI).

RESULTS

Eight studies involving 4869 cancer patients were included. Meta-analysis showed that PPI use was associated with worse overall survival (OS) (HR = 1.43, 95% CI 1.32-1.56), worse progression free survival (PFS) (HR = 1.30, 95% CI 1.20-1.40), and decreased objective response (odds ratio = 0.71, 95% CI 0.58-0.87) in cancer patients receiving PD-1/L1 inhibitors. Neither cancer type nor therapy type affected the effect of concomitant PPIs on the OS and PFS. In the subgroup of studies with a population size <500, PPIs did not reduce the OS, but the PFS. Only 1 single-center study was conducted, showing that PPI use did not affect the OS and PFS. There was no evidence of publication bias among included studies.

CONCLUSION

Concomitant PPI use was correlated with worse clinical outcomes in cancer patients treated by PD-1/L1 inhibitors. Further prospective clinical and experimental studies are needed to confirm the effect and mechanism of PPI in worsening the clinical outcome of PD-1/L1 inhibitors.

Clinical Study of Anti-PD-1 Immunotherapy Combined with Gemcitabine Chemotherapy in Multiline Treatment of Advanced Pancreatic Cancer

Objective

This study aimed to investigate the efficacy and safety of anti-PD-1 immunotherapy combined with gemcitabine chemotherapy in multiline treatment of advanced pancreatic cancer.

Methods

A retrospective analysis was performed on the clinical data of 32 patients with advanced pancreatic cancer treated with sintilimab regimen from January 2019 to December 2021 in our hospital. All patients were followed up until death or April 2022, in the form of outpatient, in-hospital review, or telephone follow-up. Follow-up content included routine blood, liver and kidney functions, tumor markers, plain or enhanced abdominal CT, and abdominal MRI examinations. Clinical efficacy was evaluated according to mRECIST criteria, and the severity of adverse effects was evaluated according to American Institute for Cancer Research (AICR) Standard Term for Adverse Events, Version 5.0.

Results

During treatment, the dosage of sintilimab was halved in 2 patients due to adverse reactions. All patients were treated with sintilimab for 1~10 times, with an average of 6 ± 4 times. The total response rate (ORR) and disease control rate (DCR) were 6.25% and 12.50% and 25.00% and 37.50%, respectively, after 1 and 3 months of treatment. The mean follow-up time of 32 patients was 1-12 months, and the median follow-up time was 4 ± 3 months. By the end point of follow-up, a total of 25 patients died, and the median progression-free survival (PFS) was 3.8 (95% CI (1.85-5.63)) months. The median overall survival (OS) was 5.1 months (95% CI (3.63~7.68). After treatment, the levels of tumor markers CA125, CEA and CA199 were partly decreased compared with those before treatment (all P < 0.001). After treatment, the blood routine indexes d-dimer, CRP (C-reactive protein), NLR (neutral granulocyte to lymphocyte ratio), and MLR (monocyte to lymphocyte ratio) decreased compared with those before treatment. In 32 patients with advanced pancreatic cancer, the adverse reactions with an incidence more than 10% included fatigue, rash, hypothyroidism, hyperuricemia, and renal insufficiency. Only 2 patients showed grade 3 fatigue symptom, and all the others showed no adverse reactions of grades 3~5. In this study, all patients' adverse reactions were relieved after symptomatic treatment.

Conclusion

Gemcitabine chemotherapy in multiline treatment of advanced pancreatic cancer with sintilimab can achieve certain clinical benefits without serious adverse reactions.

PD-1/L1 inhibitor plus chemotherapy in the treatment of sarcomas

There is an urgent clinical need for new therapeutic regimens for the effective treatment of advanced sarcomas. Accumulating evidence suggests that programmed death receptor-1/programmed death protein ligand-1 (PD-1/L1) inhibitors have synergistic effects with chemotherapy and have been approved for treatment of lung cancer, gastroesophageal cancer, and breast cancer. In this review, we reviewed the synergistic mechanism of PD-1/L1 inhibitors plus chemotherapy in the treatment of cancers, and the application of this combined regimen in several cancers, followed by a summary of the current evidence on the application of this combined regimen in the treatment of sarcomas as well as the main clinical trials currently underway. Based on the findings of this review, we believe that this combined approach will play an important role in the treatment of some subtypes of sarcomas in the future.

Anti-PD-L1 immunoconjugates for cancer therapy: Are available antibodies good carriers for toxic payload delivering?

Immune checkpoint mechanisms are important molecular cell systems that maintain tolerance toward autoantigens in order to prevent immunity-mediated accidental damage. It is well known that cancer cells may exploit these molecular and cellular mechanisms to escape recognition and elimination by immune cells. Programmed cell death protein-1 (PD-1) and its natural ligand programmed cell death ligand-1 (PD-L1) form the PD-L1/PD-1 axis, a well-known immune checkpoint mechanism, which is considered an interesting target in cancer immunotherapy. In fact, the expression of PD-L1 was found in various solid malignancies and the overactivation of PD-L1/PD-1 axis results in a poor patient survival rate. Breaking PD-L1/PD-1 axis, by blocking either the cancer side or the immune side of the axis, is currently used as anti-cancer strategy to re-establish a tumor-specific immune response. For this purpose, several blocking antibodies are now available. To date, three anti-PD-L1 antibodies have been approved by the FDA, namely atezolizumab, durvalumab and avelumab. The main advantages of anti-PD-L1 antibodies arise from the overexpression of PD-L1 antigen by a high number of tumor cells, also deriving from different tissues; this makes anti-PD-L1 antibodies potential pan-specific anti-cancer molecules. Despite the good results reported in clinical trials with anti-PD-L1 antibodies, there is a significant number of patients that do not respond to the therapy. In fact, it should be considered that, in some neoplastic patients, reduced or absent infiltration of cytotoxic T cells and natural killer cells in the tumor microenvironment or presence of other immunosuppressive molecules make immunotherapy with anti-PD-L1 blocking antibodies less effective. A strategy to improve the efficacy of antibodies is to use them as carriers for toxic payloads (toxins, drugs, enzymes, radionuclides, etc.) to form immunoconjugates. Several immunoconjugates have been already approved by FDA for treatment of malignancies. In this review, we focused on PD-L1 targeting antibodies utilized as carrier to construct immunoconjugates for the potential elimination of neoplastic cells, expressing PD-L1. A complete examination of the literature regarding anti-PD-L1 immunoconjugates is here reported, describing the results obtained in vitro and in vivo. The real potential of anti-PD-L1 antibodies as carriers for toxic payload delivery is considered and extensively discussed.

Prognostic Nutritional Index Predicts Response and Prognosis in Cancer Patients Treated With Immune Checkpoint Inhibitors: A Systematic Review and Meta-Analysis

Objective

To investigate the association between pretreatment prognostic nutritional index (PNI) and clinical survival outcomes for advanced-stage cancer patients treated with immune checkpoint inhibitors (ICIs).

Methods

We conducted a comprehensive literature search to identify eligible studies concerning the relationship between pretreatment PNI and survival outcomes in advanced cancer patients treated with ICIs. Published data were extracted and pooled odds ratio (pOR) for objective response rate (ORR), disease control rate (DCR), and pooled hazard ratio (pHR) for overall survival (OS), progressive-free survival (PFS), along with 95% confidence intervals (95% CIs) were calculated.

Results

Twelve studies with 1,359 participants were included in our study. A higher level of PNI indicated a greater ORR (pOR = 2.17, 95% CI = 1.52–3.10) and favorable DCR (pOR = 2.48, 95% CI = 1.87–3.29). Low PNI was associated with a shorter OS (pHR = 2.24, 95% CI = 1.57–3.20) and unfavorable PFS (pHR = 1.61, 95% CI = 1.37–1.88).

Conclusion

Low PNI might be an effective biomarker of poor tumor response and adverse prognosis of advanced cancer patients with ICIs. Further studies are needed to verify the prognostic value of PNI in clinical practice.

Hyperprogression, a challenge of PD-1/PD-L1 inhibitors treatments: potential mechanisms and coping strategies

Immunotherapy is now a mainstay in cancer treatments. Programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) immune checkpoint inhibitor (ICI) therapies have opened up a new venue of advanced cancer immunotherapy. However, hyperprogressive disease (HPD) induced by PD-1/PD-L1 inhibitors caused a significant decrease in the overall survival (OS) of the patients, which compromise the efficacy of PD-1/PD-L1 inhibitors. Therefore, HPD has become an urgent issue to be addressed in the clinical uses of PD-1/PD-L1 inhibitors. The mechanisms of HPD remain unclear, and possible predictive factors of HPD are not well understood. In this review, we summarized the potential mechanisms of HPD and coping strategies that can effectively reduce the occurrence and development of HPD.

Autoimmune hemolytic anemia in patients with relapsed Hodgkin's lymphoma after treatment with penpulimab, a monoclonal antibody against programmed death receptor-1

In August 2021, penpulimab, an anti-programmed cell death 1 (PD-1) monoclonal antibody, was approved in China for the treatment of adult patients with relapsed or refractory classic Hodgkin's lymphoma who completed at least second-line chemotherapy. Penpulimab is currently in clinical trials in China and Australia for the treatment of nasopharyngeal cancer and non-small cell lung cancer. Several clinical studies have shown that penpulimab is safe and effective, and no immune-related adverse events (irAEs) above grade 3 were observed. A 60-year-old woman with relapsed Hodgkin's lymphoma developed nausea and fatigue after receiving penpulimab monotherapy (200 mg every 2 weeks). Ten days after the second injection, the patient's condition worsened, and biochemical test results confirmed autoimmune hemolytic anemia (AIHA), with a hemoglobin level of 70 g/L (normal range, 115-150 g/L), an unconjugated bilirubin level of 19.08 µmol/L (normal range, 0-17 µmol/L), and positive direct antiglobulin test (DAT) results. On the same day, we treated her with prednisone (2 mg/kg), but her hemoglobin level continued to decline to 51 g/L one day after hormone therapy, so she received an intravenous infusion of washed red blood cells and underwent plasmapheresis, which eventually resolved the AIHA. Considering that the hemoglobin level was < 65 g/L and the irAE was grade 4, penpulimab was discontinued, and the symptoms of AIHA disappeared. From this event, we know that severe AIHA can occur after penpulimab use similar to other PD-1 antibodies. In this case, plasmapheresis showed a good therapeutic effect and should be used as a supplementary means when hormonal and immunosuppressive therapies cannot provide rapid symptom relief. In addition, we recommend regular direct antiglobulin testing, as well as haptoglobin, lactate dehydrogenase and other hemolysis-related laboratory tests, in patients prescribed penpulimab and similar drugs for the early diagnosis and treatment of AIHA.

Everolimus (RAD001) combined with programmed death-1 (PD-1) blockade enhances radiosensitivity of cervical cancer and programmed death-ligand 1 (PD-L1) expression by blocking the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR)/S6 kinase 1 (S6K1) pathway

Cervical cancer (CC) is the 4^th most prevalent malignancy in females. This study explored the mechanism of everolimus (RAD001) combined with programmed death-1 (PD-1) blockade on radiosensitivity by phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway and autophagy in CC cells. Low-radiosensitive CaSki cells were selected as study objects. After RAD001 treatment, PI3K/AKT/mTOR pathway activation, autophagy, migration and invasion abilities, autophagy-related proteins (LC3-I, LC3-II, and p62), and PD-L1 expression in CC cells were detected. After triple treatment of radiotherapy (RT), RAD001, and PD-1 blockade to the CC mouse models, tumor weight and volume were recorded. Ki67 expression, the number of CD8 + T cells, and the ability to produce IFN-γ and TNF-α in tumor tissues were determined. RAD001 promoted autophagy by repressing PI3K/AKT/mTOR pathway, augmented RT-induced apoptosis, and weakened migration and invasion, thereby increasing CC cell radiosensitivity. RAD001 elevated RT-induced PD-L1 level. RT combined with RAD001 and PD-1 blockade intensified the inhibitory effect of RT on tumor growth, reduced the amount of Ki67-positive cells, enhanced radiosensitivity of CC mice, and increased the quantity and killing ability of CD8 + T cells. Briefly, RAD001 combined with PD-1 blockade increases radiosensitivity of CC by impeding the PI3K/AKT/mTOR pathway and potentiating cell autophagy.

A Generic Strategy to Generate Bifunctional Two-in-One Antibodies by Chicken Immunization

Various formats of bispecific antibodies exist, among them Two-in-One antibodies in which each Fab arm can bind to two different antigens. Their IgG-like architecture accounts for low immunogenicity and also circumvents laborious engineering and purification steps to facilitate correct chain pairing. Here we report for the first time the identification of a Two‐in‐One antibody by yeast surface display (YSD) screening of chicken-derived immune libraries. The resulting antibody simultaneously targets the epidermal growth factor receptor (EGFR) and programmed death‐ligand 1 (PD-L1) at the same Fv fragment with two non-overlapping paratopes. The dual action Fab is capable of inhibiting EGFR signaling by binding to dimerization domain II as well as blocking the PD-1/PD-L1 interaction. Furthermore, the Two-in-One antibody demonstrates specific cellular binding properties on EGFR/PD-L1 double positive tumor cells. The presented strategy relies solely on screening of combinational immune-libraries and obviates the need for any additional CDR engineering as described in previous reports. Therefore, this study paves the way for further development of therapeutic antibodies derived from avian immunization with novel and tailor-made binding properties.

Efficacy, safety and prognostic factors of camrelizumab plus carboplatin and pemetrexed chemotherapy in advanced lung adenocarcinoma patients

WHAT IS KNOWN AND OBJECTIVE

Camrelizumab is a recently developed PD-1 inhibitor in China applied in treating different cancers including lung cancer. This study is designed to evaluate the efficacy, safety and prognostic factors for camrelizumab plus carboplatin and pemetrexed (CP) chemotherapy in treating patients with advanced lung adenocarcinoma.

METHODS

Of 51 advanced lung adenocarcinoma patients with negative driver genes who received camrelizumab plus CP chemotherapy were recruited. These patients received four cycles of camrelizumab plus CP chemotherapy in a 21-day cycle. Then, camrelizumab, pemetrexed or camrelizumab plus pemetrexed was administered as maintenance therapy.

RESULTS AND DISCUSSION

The rates of complete response, partial response, stable disease and progressive disease were 2.0%, 56.8%, 19.6% and 5.9%, respectively; while treatment response of 15.7% of patients was missing or not evaluable. The objective response and disease control rates were 58.8% and 78.4%, respectively. With a median follow-up period of 14.9 months (the follow-up duration ranged from 3.9 months to 24.3 months), 41 (83.4%) cases of disease progression and 22 (43.1%) cases of death were recorded. The median progression-free survival (PFS) was 10.5 months (95% confidence interval (CI): 8.4-12.6 months) with a 1-year PFS rate of 36.3% and a 2-year PFS rate of 7.5%. In addition, the median overall survival (OS) was 18.7 months (95% CI: 16.4-21.0 months) with a 1-year OS rate of 79.1% and a 2-year OS rate of 30.4%. In consideration of safety, the most frequent adverse events were peripheral neuropathy (37.3%), neutropenia (37.3%), alopecia (35.3%), etc. and most of them were grade 1-2 and could be controlled.

WHAT IS NEW AND CONCLUSION

Camrelizumab plus CP chemotherapy achieves favourable efficacy and tolerable adverse events in advanced lung adenocarcinoma patients.

Tumor immunotherapies by immune checkpoint inhibitors (ICIs); the pros and cons

The main breakthrough in tumor immunotherapy was the discovery of immune checkpoint (IC) proteins, which act as a potent suppressor of the immune system by a myriad of mechanisms. After that, scientists focused on the immune checkpoint molecules mainly. Thereby, much effort was spent to progress novel strategies for suppressing these inhibitory axes, resulting in the evolution of immune checkpoint inhibitors (ICIs). Then, ICIs have become a promising approach and shaped a paradigm shift in tumor immunotherapies. CTLA-4 plays an influential role in attenuation of the induction of naïve and memory T cells by engagement with its responding ligands like B7-1 (CD80) and B7-2 (CD86). Besides, PD-1 is predominantly implicated in adjusting T cell function in peripheral tissues through its interaction with programmed death-ligand 1 (PD-L1) and PD-L2. Given their suppressive effects on anti-tumor immunity, it has firmly been documented that ICIs based therapies can be practical and rational therapeutic approaches to treat cancer patients. Nonetheless, tumor inherent or acquired resistance to ICI and some treatment-related toxicities restrict their application in the clinic. The current review will deliver a comprehensive overview of the ICI application to treat human tumors alone or in combination with other modalities to support more desired outcomes and lower toxicities in cancer patients. Video Abstract.

Tumor Microenvironment of Hepatocellular Carcinoma: Challenges and Opportunities for New Treatment Options

The prevalence of liver cancer is constantly rising, with increasing incidence and mortality in Europe and the USA in recent decades. Among the different subtypes of liver cancers, hepatocellular carcinoma (HCC) is the most commonly diagnosed liver cancer. Besides advances in diagnosis and promising results of pre-clinical studies, HCC remains a highly lethal disease. In many cases, HCC is an effect of chronic liver inflammation, which leads to the formation of a complex tumor microenvironment (TME) composed of immune and stromal cells. The TME of HCC patients is a challenge for therapies, as it is involved in metastasis and the development of resistance. However, given that the TME is an intricate system of immune and stromal cells interacting with cancer cells, new immune-based therapies are being developed to target the TME of HCC. Therefore, understanding the complexity of the TME in HCC will provide new possibilities to design novel and more effective immunotherapeutics and combinatorial therapies to overcome resistance to treatment. In this review, we describe the role of inflammation during the development and progression of HCC by focusing on TME. We also describe the most recent therapeutic advances for HCC and possible combinatorial treatment options.

Structural basis of HLX10 PD-1 receptor recognition, a promising anti-PD-1 antibody clinical candidate for cancer immunotherapy

Cancer immunotherapies, such as checkpoint blockade of programmed cell death protein-1 (PD-1), represents a breakthrough in cancer treatment, resulting in unprecedented results in terms of overall and progression-free survival. Discovery and development of novel anti PD-1 inhibitors remains a field of intense investigation, where novel monoclonal antibodies (mAbs) and novel antibody formats (e.g., novel isotype, bispecific mAb and low-molecular-weight compounds) are major source of future therapeutic candidates. HLX10, a fully humanized IgG4 monoclonal antibody against PD-1 receptor, increased functional activities of human T-cells and showed in vitro, and anti-tumor activity in several tumor models. The combined inhibition of PD-1/PDL-1 and angiogenesis pathways using anti-VEGF antibody may enhance a sustained suppression of cancer-related angiogenesis and tumor elimination. To elucidate HLX10's mode of action, we solved the structure of HLX10 in complex with PD-1 receptor. Detailed epitope analysis showed that HLX10 has a unique mode of recognition compared to the clinically approved PD1 antibodies Pembrolizumab and Nivolumab. Notably, HLX10's epitope was closer to Pembrolizumab's epitope than Nivolumab's epitope. However, HLX10 and Pembrolizumab showed an opposite heavy chain (HC) and light chain (LC) usage, which recognizes several overlapping amino acid residues on PD-1. We compared HLX10 to Nivolumab and Pembrolizumab and it showed similar or better bioactivity in vitro and in vivo, providing a rationale for clinical evaluation in cancer immunotherapy.

Communication pathways bridge local and global conformations in an IgG4 antibody

The affinity of an antibody for its antigen is primarily determined by the specific sequence and structural arrangement of the complementarity-determining regions (CDRs). Recent evidence, however, points toward a nontrivial relation between the CDR and distal sites: variations in the binding strengths have been observed upon mutating residues separated from the paratope by several nanometers, thus suggesting the existence of a communication network within antibodies, whose extension and relevance might be deeper than insofar expected. In this work, we test this hypothesis by means of molecular dynamics (MD) simulations of the IgG4 monoclonal antibody pembrolizumab, an approved drug that targets the programmed cell death protein 1 (PD-1). The molecule is simulated in both the apo and holo states, totalling 4 μs of MD trajectory. The analysis of these simulations shows that the bound antibody explores a restricted range of conformations with respect to the apo one, and that the global conformation of the molecule correlates with that of the CDR. These results support the hypothesis that pembrolizumab featues a multi-scale hierarchy of intertwined global and local conformational changes. The analysis pipeline developed in this work is general, and it can help shed further light on the mechanistic aspects of antibody function.

Chimeric Antigen Receptor T-Cell Therapy in Lung Cancer: Potential and Challenges

Chimeric antigen receptor T (CAR-T) cell therapy has exhibited a substantial clinical response in hematological malignancies, including B-cell leukemia, lymphoma, and multiple myeloma. Therefore, the feasibility of using CAR-T cells to treat solid tumors is actively evaluated. Currently, multiple basic research projects and clinical trials are being conducted to treat lung cancer with CAR-T cell therapy. Although numerous advances in CAR-T cell therapy have been made in hematological tumors, the technology still entails considerable challenges in treating lung cancer, such as on−target, of−tumor toxicity, paucity of tumor-specific antigen targets, T cell exhaustion in the tumor microenvironment, and low infiltration level of immune cells into solid tumor niches, which are even more complicated than their application in hematological tumors. Thus, progress in the scientific understanding of tumor immunology and improvements in the manufacture of cell products are advancing the clinical translation of these important cellular immunotherapies. This review focused on the latest research progress of CAR-T cell therapy in lung cancer treatment and for the first time, demonstrated the underlying challenges and future engineering strategies for the clinical application of CAR-T cell therapy against lung cancer.

Comparative Impact of PD-1 and PD-L1 Inhibitors on Advanced Esophageal or Gastric/Gastroesophageal Junction Cancer Treatment: A Systematic Review and Meta-Analysis

Programmed death 1 (PD-1) and PD ligand 1 (PD-L1) inhibitors have demonstrated varying effectiveness in treating esophageal or gastric/gastroesophageal junction (G/GEJ) cancer. Hence, this systematic review and meta-analysis evaluated the efficacy and safety of anti-PD-1/PD-L1 treatment in patients with esophageal or G/GEJ cancer by analyzing the types of medications. Randomized controlled trials comparing anti-PD-1/PD-L1 to control therapy were identified by searching PubMed, EMBASE, and ClinicalTrials.gov. The outcomes included overall survival (OS), progression-free survival (PFS) rates, and serious adverse events (SAEs), evaluating the differences in therapy types, including a comparison between PD-1 and PD-L1 inhibitors. Eight studies were included in the analysis. PD-1/PD-L1 inhibitors affected the overall OS rate increment without influencing the PFS rate (HR, 0.837; 95% CI, 0.753-0.929; p = 0.001; HR 0.991; 95% CI, 0.778-1.263; p = 0.942, respectively). Anti-PD-1 was significantly more beneficial for increasing OS and PFS than PD-L1 inhibitors. Anti-PD-1 and PD-L1 use was not significantly associated with SAE development in esophageal or G/GEJ cancer patients. PD-1/PD-L1 inhibitor use was associated with improved OS and PFS rate increase among PD-1 and PD-L1 inhibitors. Considering response variations to anti-PD-1/PD-L1 usage, more individualized treatments should be introduced in clinical practice.

Syntheses, Biological Evaluations, and Mechanistic Studies of Benzo[c][1,2,5]oxadiazole Derivatives as Potent PD-L1 Inhibitors with In Vivo Antitumor Activity

A series of novel benzo[c][1,2,5]oxadiazole derivatives were designed, synthesized, and biologically evaluated as inhibitors of PD-L1. Among them, compound L7 exhibited 1.8 nM IC50 value in a homogeneous time-resolved fluorescence (HTRF) assay, which was 20-fold more potent than the lead compound BMS-1016. In the surface plasmon resonance (SPR) assay, L7 bound to human PD-L1 (hPD-L1) with a KD value of 3.34 nM, without showing any binding to hPD-1. In the cell-based coculture assay, L7 blocked PD-1/PD-L1 interaction with an EC50 value of 375 nM, while BMS-1016 had an EC50 value of 2075 nM. Moreover, compound L24, an ester prodrug of L7, was orally bioavailable and displayed significant antitumor effects in tumor models of syngeneic and PD-L1 humanized mice. Mechanistically, L24 exhibited significant in vivo antitumor effects probably through promoting antitumor immunity. Together, this series of benzoxadiazole PD-L1 inhibitors holds promise for tumor immunotherapy. Preclinical trials with selected compounds are ongoing in our laboratory.

Design of a Trispecific Checkpoint Inhibitor and Natural Killer Cell Engager Based on a 2 + 1 Common Light Chain Antibody Architecture

Natural killer cell engagers gained enormous interest in recent years due to their potent anti-tumor activity and favorable safety profile. Simultaneously, chicken-derived antibodies entered clinical studies paving the way for avian-derived therapeutics. In this study, we describe the affinity maturation of a common light chain (cLC)-based, chicken-derived antibody targeting EGFR, followed by utilization of the same light chain for the isolation of CD16a- and PD-L1-specific monoclonal antibodies. The resulting binders target their respective antigen with single-digit nanomolar affinity while blocking the ligand binding of all three respective receptors. Following library-based humanization, bispecific and trispecific variants in a standard 1 + 1 or a 2 + 1 common light chain format were generated, simultaneously targeting EGFR, CD16a, and PD-L1. The trispecific antibody mediated an elevated antibody-dependent cellular cytotoxicity (ADCC) in comparison to the EGFR×CD16a bispecific variant by effectively bridging EGFR/PD-L1 double-positive cancer cells with CD16a-positive effector cells. These findings represent, to our knowledge, the first detailed report on the generation of a trispecific 2 + 1 antibodies exhibiting a common light chain and illustrate synergistic effects of trispecific antigen binding. Overall, this generic procedure paves the way for the engineering of tri- and oligospecific therapeutic antibodies derived from avian immunizations.

Obatoclax, the pan-Bcl-2 inhibitor sensitizes hepatocellular carcinoma cells to promote the anti-tumor efficacy in combination with immune checkpoint blockade

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Obatoclax, the Bcl-2 inhibitor directly impaired HCC cell growth.

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Obatoclax suppressed HCC development in vivo.

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Obatoclax sensitized HCC cells to T cell-mediated killing.

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Combination therapy of obatoclax and anti-PD-1 antibody synergically reduced HCC growth.

Bcl-2 family proteins play critical roles in regulating lymphocyte development and maintain homeostasis, and have also been proved to be involved in various cancer types development. However, the role of Bcl-2 in hepatocellular carcinoma (HCC) development has not been clearly studied. Here, we reported the pan-Bcl-2 inhibitor, obatoclax could directly inhibit HCC growth in vitro. We further demonstrated in murine HCC model that obatoclax also suppressed HCC development in vivo. We also proved that although obatoclax inhibited T cells expansion, it had no influence on T cells activation in vivo. Mechanism study revealed that obatoclax sensitized HCC cells to T cell-mediated killing. Combination therapy of obatoclax with anti-PD-1 antibody synergistically suppressed HCC development and prolonged the survival rate of tumor-bearing mice. The combination therapy promoted T cells activation and effector cytokines expression both in spleen and tumor. In summary, our results proved that obatoclax sensitized HCC cells to T cell -mediated killing. Combination of obatoclax with immune checkpoint blockade served as a promising therapeutic strategy for HCC treatment.

Melanoma is associated with an increased risk of bullous pemphigoid: a large population-based longitudinal study

The association between bullous pemphigoid (BP) and melanoma is yet to be investigated. We aimed to assess assess the bidirectional association between BP and melanoma and to delineate the epidemiological features of patients with both diagnoses. A population-based cohort study was performed comparing BP patients (n = 3924) with age-, sex- and ethnicity-matched control subjects (n = 19,280) with regard to incident cases of melanoma. A case-control design was additionally adopted to estimate the risk of BP in individuals with a preexisting diagnosis of melanoma. The prevalence of preexisting melanoma was higher in patients with BP than in control subjects (1.5% vs. 1.0%, respectively; P = 0.004). A history of melanoma confers a 50% increase in the risk of subsequent BP (OR 1.53; 95% CI 1.14-2.06). This risk was higher among males (OR 1.66; 95% CI 1.09-2.54) and individuals older than 80 years (OR 1.63; 95% CI 1.11-2.38), and persisted after adjustment for multiple putative confounders including PD-1/PDL-1 antagonists (adjusted OR 1.53; 95% CI 1.14-2.06). Conversely, the risk of melanoma among patients with BP was slightly elevated, but did not reach the level of statistical significance (adjusted HR 1.13; 95% CI 0.73-1.74). Patients with a dual diagnosis of BP and melanoma were older at the onset of BP and had lower body mass index. A history of melanoma is associated with a 50% increase in the incidence of subsequent BP. Physicians managing patients with both conditions should be aware of this association. Further research is warranted to reveal the underlying mechanism of these findings.

Belantamab mafodotin in combination with novel agents in relapsed/refractory multiple myeloma: DREAMM-5 study design

Belantamab mafodotin (belamaf) is a BCMA-targeted antibody-drug conjugate recently approved as monotherapy for adults with relapsed/refractory multiple myeloma who have received ≥4 prior therapies. Belamaf binds to BCMA and eliminates myeloma cells by multimodal mechanisms of action. The cytotoxic and potential immunomodulatory properties of belamaf have led to novel combination studies with other anticancer therapies. Here, we describe the rationale and design of DREAMM-5, an ongoing Phase I/II platform study evaluating the safety and efficacy of belamaf combined with novel agents, including GSK3174998 (OX40 agonist), feladilimab (an ICOS; GSK3359609), nirogacestat (a gamma-secretase inhibitor; PF-03084014) and dostarlimab (a PD-1 blocker) versus belamaf monotherapy for patients with relapsed/refractory multiple myeloma. Clinical trial registration: NCT04126200 (ClinicalTrials.gov).

Understanding Inflammasomes and PD-1/PD-L1 Crosstalk to Improve Cancer Treatment Efficiency

Inflammasomes and immune checkpoints have been shown to participate in carcinogenesis, cancer growth and response to treatment. Thus, targeting cytokines resulting from inflammasome activation, such as interleukin (IL)-1β, has emerged as a new tool in the therapeutic arsenal. Moreover, the use of checkpoint inhibitors such as anti-PD-1 or anti-PD-L1 has revolutionized the treatment of some cancer patients. However, inflammasome activation and consecutive cytokine release only occurs in some chemotherapeutic treatments and immune checkpoint inhibitors only work for a restricted number of patients, thus limiting the use of therapies targeting these pathways. Expanding knowledge about the inefficiency of these therapies recently brought forward the hypothesis of targeting both pathways. In this review, we provide an overview of the crosstalk between inflammasomes and programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) that might explain how these two pathways are mutually dependent, and perhaps why targeting only one of them leads to inefficiency of cancer treatment in some patients.

The Stone Guest: How Does pH Affect Binding Properties of PD-1/PD-L1 Inhibitors?

The interaction between programmed cell death-1 (PD-1) and its ligand PD-L1 activates a coinhibitory signal that blocks T-cell activation, promoting the immune escape process in the tumor microenvironment. Development of monoclonal antibodies targeting and inhibiting PD-1/PD-L1 interaction as anticancer immunotherapies has proved successful in multiple clinical settings and for various types of cancer. Notwithstanding, limitations exist with the use of these biologics, including drug resistance and narrow therapeutic response rate in a majority of patients, that demand for the design of more efficacious small molecule-based immunotherapies. Alteration of pH in the tumor microenvironment is a key factor that is involved in promoting drug resistance, tumor survival and progression. In this study, we have investigated the effect of pH shifts on binding properties of distinct classes of PD-L1 inhibitors, including macrocyclic peptide and small molecules. Results expand structure-activity relationships of PD-L1 inhibitors, providing insights into structural features and physicochemical properties that are useful for the design of ligands that may escape a drug resistance mechanism associated to variable pH conditions of tumor microenvironment.