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

Targeting PD-1/PD-L1 in tumor immunotherapy: Mechanisms and interactions with host growth regulatory pathways

Tumor immunotherapy has garnered considerable attention, emerging as a new standard of care in cancer treatment. The conventional targets, such as VEGF and EGFR, have been extended to others including BRAF and PD-1/PD-L1, which have shown significant potential in recent cancer treatments. This review aims to succinctly overview the impact and mechanisms of therapies that modulate PD-1/PD-L1 expression by targeting VEGF, EGFR, LAG-3, CTLA-4 and BRAF. We investigated how modulation of PD-1/PD-L1 expression impacts growth factor signaling, shedding light on the interplay between immunomodulatory pathways and growth factor networks within the tumor microenvironment. By elucidating these interactions, we aim to provide insights into novel potential synergistic therapeutic strategies for cancer immunotherapy.

Residue-Specific Epitope Mapping of the PD-1/Nivolumab Interaction Using X-ray Footprinting Mass Spectrometry

X-ray footprinting coupled with mass spectrometry (XFMS) presents a novel approach in structural biology, offering insights into protein conformation and dynamics in the solution state. The interaction of the cancer-immunotherapy monoclonal antibody nivolumab with its antigen target PD-1 was used to showcase the utility of XFMS against the previously published crystal structure of the complex. Changes in side-chain solvent accessibility, as determined by the oxidative footprint of free PD-1 versus PD-1 bound to nivolumab, agree with the binding interface side-chain interactions reported from the crystal structure of the complex. The N-linked glycosylation sites of PD-1 were confirmed through an LC-MS/MS-based deglycosylation analysis of asparagine deamidation. In addition, subtle changes in side-chain solvent accessibility were observed in the C'D loop region of PD-1 upon complex formation with nivolumab.

First-line serplulimab in metastatic colorectal cancer: Phase 2 results of a randomized, double-blind, phase 2/3 trial

BACKGROUND

Whether or not the addition of immunotherapy to current standard-of-care treatments can improve efficacy in proficient mismatch repair (pMMR)/microsatellite-stable (MSS) metastatic colorectal cancer (mCRC), the predominant type of mCRC, is unclear.

METHODS

This randomized, double-blind, phase 2 part of a phase 2/3 trial was conducted at 23 hospitals across China (ClinicalTrials.gov: NCT04547166). Patients with unresectable metastatic/recurrent colorectal adenocarcinoma and no prior systemic therapy were randomly assigned 1:1 to receive every-3-weeks intravenous serplulimab (300 mg) plus HLX04 (7.5 mg/kg) and XELOX (serplulimab group) or placebo (300 mg) plus bevacizumab (7.5 mg/kg) and XELOX (placebo group). The primary endpoint was independent radiology review committee (IRRC)-assessed progression-free survival (PFS). Secondary endpoints included other efficacy endpoints and safety.

FINDINGS

Between July 16, 2021, and January 20, 2022, 114 patients were enrolled and randomly assigned to the serplulimab (n = 57) or placebo (n = 57) group. All patients had stage IV CRC, and 95.7% of the patients with available microsatellite instability (MSI) status were MSS. With a median follow-up duration of 17.7 months, median PFS was prolonged in the serplulimab group (17.2 vs. 10.7 months; hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.31-1.14). Although the median overall survival (OS) was not reached for either group, a trend of an OS benefit was observed for the serplulimab group (HR, 0.77; 95% CI, 0.41-1.45). 36 (65.5%) and 32 (56.1%) patients in the serplulimab and placebo groups had grade ≥3 treatment-related adverse events, respectively.

CONCLUSIONS

Serplulimab plus HLX04 and XELOX exhibits promising efficacy and is safe and tolerable in patients with treatment-naive mCRC.

FUNDING

This work was funded by Shanghai Henlius Biotech, Inc.

The Optimal First-Line Therapy for Extensive-Stage Small-Cell Lung Cancer Based on Liver Metastasis Status: A Network Meta-Analysis and Systematic Review

PURPOSE

To compare the efficacy of first-line regimens based on programmed cell death (or ligand) [PD-(L)1] blockade in extensive-stage small-cell lung cancer (ES-SCLC) patients with or without liver metastases (LM), and to identify optimal treatment strategies.

METHODS

Network meta-analysis of randomized controlled trials (RCTs) comparing chemo-immunotherapy (CIT) and chemotherapy (CT) in ES-SCLC patients stratified by LM. Overall survival (OS) and progression-free survival (PFS) were evaluated using hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Seven RCTs involving 3658 ES-SCLC patients (1243 with LM, 2415 without LM) were analyzed. For patients with LM, the combination therapies of anti-PD-1 + CT (HR, 0.67; 95% CI, 0.54%-0.82%; p < 0.001) and anti-PD-L1 + CT + anti-angiogenesis (HR, 0.84; 95% CI, 0.71%-0.99%; p = 0.042) demonstrated superior efficacy in prolonging OS compared to CT alone. The anti-PD-1 + CT regimen had the highest cumulative probability of 91.6% for extending OS in patients with LM. For patients without LM, all CIT regimens resulted in improved OS compared to CT alone, with the regimen of anti-angiogenesis + anti-PD-L1 + CT ranking first and having the highest cumulative probability of 95.5% for prolonging OS.

CONCLUSIONS

CIT is effective for ES-SCLC patients regardless of LM status. For patients with LM, PD-1 blockade combined with CT is the best option. For patients without LM, the most beneficial regimen is the combination of anti-angiogenesis, PD-L1 blockade, and CT.

Dostarlimab: A promising new PD-1 inhibitor for cancer immunotherapy

OBJECTIVE

Dostarlimab, a humanized monoclonal PD-1 blocking antibody, is being tested as a cancer therapy in this review. Specifically, it addresses mismatch repair failure in endometrial cancer and locally progressed rectal cancer patients.

DATA SOURCES

A thorough database search found Dostarlimab clinical trials and studies. Published publications and ongoing clinical trials on Dostarlimab's efficacy as a single therapy and in conjunction with other medicines across cancer types were searched.

DATA SUMMARY

The review recommends Dostarlimab for endometrial cancer mismatch repair failure, as supported by GARNET studies. The analysis also highlights locally advanced rectal cancer findings. In the evolving area of cancer therapy, immune checkpoint inhibitors including pembrolizumab, avelumab, atezolizumab, nivolumab, and durvalumab were discussed.

CONCLUSIONS

Locally advanced rectal cancer patients responded 100% to Dostarlimab. Many clinical trials, including ROSCAN, AMBER, IOLite, CITRINO, JASPER, OPAL, PRIME, PERLA, and others, are investigating Dostarlimab in combination treatment. This research sheds light on Dostarlimab's current and future possibilities, in improving cancer immunotherapy understanding.

Serplulimab combined with gemcitabine, nab-paclitaxel and stereotactic body radiotherapy as the first-line treatment for patients with metastatic pancreatic adenocarcinoma in China: a multicentre, single-arm, phase II trial (ICSBR) protocol

INTRODUCTION

Patients with pancreatic ductal adenocarcinoma (PDAC) remain a poor prognosis despite the development of chemotherapy. Although programmed cell death 1 (PD-1) blockade has shown great efficacy in various solid tumours, its application in treating PDAC is limited. Recent studies have indicated that chemotherapy or stereotactic body radiotherapy (SBRT) may improve the antitumour effect of PD-1 blockade in patients with PDAC. The objective of this study is to evaluate the efficacy and safety of combined therapy comprising PD-1 blockade, gemcitabine plus nab-paclitaxel chemotherapy and SBRT for patients with metastatic PDAC.

METHODS AND ANALYSIS

This is a multicentre, single-arm, prospective phase II clinical trial. Forty-three patients diagnosed with metastatic PDAC will be enrolled. The eligible patients will be intravenously administered 1000 mg/m2 gemcitabine and 125 mg/m2 nab-paclitaxel on days 1 and 8 of the 21-day cycle. Serplulimab (200 mg) will be administered intravenously on day 1 of the 21-day cycle. Furthermore, during the second cycle, the patients will undergo SBRT with doses of 33 Gy in five fractions for primary lesions or doses of 24 Gy in three fractions for metastases. The primary endpoint is the 6-month progression-free survival (PFS) rate. The secondary endpoints overall survival, PFS, overall response rate, disease control rate, time to progression, duration of response, duration of disease control and safety. Moreover, this trial seeks to investigate biomarkers such as circulating tumour DNA and circulating hybrid cells in patients diagnosed with metastatic PDAC.

ETHICS AND DISSEMINATION

The study was approved by the Ethics Committee on Biomedical Research, West China Hospital of Sichuan University. The study results will be presented at international conferences and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2300073237.

Efficacy and safety of different immunotherapies combined with chemotherapy as first-line therapy in patients with small cell lung cancer: a network meta-analysis

Background

The efficacy and safety of different immunosuppressants combined with chemotherapy in treating patients with small-cell lung cancer (extensive-disease small-cell lung cancer, limited-disease small-cell lung cancer and relapsed small-cell lung cancer) are still unknown, and there are no reports directly comparing the efficacy and safety of other immunotherapies.

Objective

This study aimed to compare the efficacy and safety of first-line immunotherapy combined with chemotherapy in patients with small-cell lung cancer.

Method

We searched Pubmed, Embase, Cochrane Library, CNKI, and Wanfang databases for relevant articles published from inception to November 11, 2020. The risk of bias of the included studies was conducted using the Cochrane risk-of-bias (RoB) tool. Multiple Bayesian network meta-analyses were performed. They conducted data analysis using R Studio and STATA version 15.1. The outcomes comprised overall survival (OS), progression-free survival (PFS), stability of response (SOR), duration of response (DOR) and adverse events of grade 3 or higher (AE grade≥3). A 95% confidence interval (CI) was provided for each estimate.

Results

This meta-analysis included 16 RCT studies with 5898 patients. For OS, relative to chemotherapy (MD=-4.49; 95%CI [-7.97, -1.03]), durvalumab plus tremelimumab (MD=-4.62; 95%CI [-9.08, -0.11]), ipilimumab (MD=-4.26; 95%CI [-8.01, -0.3]) and nivolumab(MD=-5.66; 95%CI [-10.44, -1.11]) and nivolumab plus ipilimumab (MD=-4.56; 95%CI [-8.7, -0.1]), serplulimab can significantly increase the OS of SCLC patients. There was no significant difference between PFS, SOR and DOR. Analysis of AE showed that different immunotherapy combined chemotherapy regimens were similar to single chemotherapy regarding the overall incidence of AE grade≥3. However, after the cumulative ranking of the common symptoms of different adverse reactions, it was found that nivolumab ranked first in the occurrence probability of anemia (99.08%), fatigue (84.78%), and decreased appetite (89.66%). durvalumab was the most likely in nausea (75.4%). Pembrolizumab (76.24%) was most likely to cause pruritus. Chemotherapy combined with immunotherapy caused less diarrhea than chemotherapy alone (80.16%).

Conclusions

According to our analysis, serplulimab combined with chemotherapy is more likely to show better efficacy with a manageable safety profile for small-cell lung cancer. However, the evidence for this comparison shows some limitations due to the number of literature.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023486053.

Safety, Tolerability, and Preliminary Efficacy of Serplulimab, a Novel Anti-PD-1 Antibody, in Patients with Metastatic or Recurrent Solid Tumors: A Phase I Study

BACKGROUND

Serplulimab is a novel, recombinant, humanized, monoclonal, anti-programmed death 1 antibody with a similar or better affinity and pre-clinical antitumor activity than pembrolizumab and nivolumab.

OBJECTIVE

This phase I, open-label, dose-escalation study evaluated serplulimab in patients with advanced solid tumors. The second interim analysis of the dose-finding phase is reported here.

METHODS

Adult patients with histologically confirmed metastatic/recurrent solid tumors who had progressed on, or were intolerant to/clinically unsuitable for standard treatment, were enrolled. Four intravenous serplulimab dose levels were evaluated: 0.3, 1.0, 3.0, and 10.0 mg/kg every 2 weeks in 28-day cycles for up to 2 years. Primary endpoints were the incidence of treatment-emergent adverse events and the maximum tolerated dose.

RESULTS

By 27 July, 2020 (data cut-off), 29 patients with stage IV disease (34.5% with lung cancer) received one or more doses of serplulimab. One (3.4%) patient had completed treatment and 26 (89.7%) had discontinued from the study. The maximum tolerated dose was not reached. Twenty-two (75.9%) patients experienced treatment-emergent adverse events related to serplulimab, most frequently nausea (24.1%), with no notable differences in incidence between dose cohorts; of these, grade ≥ 3 events occurred in four (13.8%) patients. Pharmacokinetic data demonstrated minimal accumulation of serplulimab after repeated administration. Functional programmed death 1 blockade was observed across dose levels. Objective response and disease control rates were 8.0 and 60.0%, respectively.

CONCLUSIONS

Serplulimab was well tolerated and demonstrated antitumor activity. These data support further study of serplulimab in larger patient populations.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03468751 (19 March, 2018).

A global phase 3 study of serplulimab plus chemotherapy as first-line treatment for advanced squamous non-small-cell lung cancer (ASTRUM-004)

Combining immunotherapy with chemotherapy can provide improved survival in advanced squamous non-small-cell lung cancer (NSCLC) patients without targetable gene alterations. 537 previously untreated patients with stage IIIB/IIIC or IV squamous NSCLC without targetable gene alterations were enrolled and randomized (2:1) to receive serplulimab 4.5 mg/kg or placebo, both in combination with nab-paclitaxel and carboplatin, intravenously in 3-week cycles. The primary endpoint of progression-free survival (PFS) was met at the first interim analysis. At the second interim analysis, PFS benefit was maintained in serplulimab-chemotherapy group (hazard ratio [HR] 0.53, 95% confidence interval [CI] 0.42-0.67). At the final analysis, serplulimab-chemotherapy significantly improved median OS compared to placebo-chemotherapy (HR 0.73, 95% CI 0.58-0.93; p = 0.010). Grade ≥3 serplulimab or placebo-related adverse events occurred in 126 (35.2%) and 58 (32.4%) patients, respectively. Our results demonstrate that adding serplulimab to chemotherapy significantly improves survival in advanced squamous NSCLC patients, with manageable safety.

Re-inventing a better wheel? Serplulimab for squamous cell lung cancer

Immune checkpoint inhibitors have reshaped the treatment landscape of non-small cell lung cancer (NSCLC). However, chemoimmunotherapy trials dedicated to squamous NSCLC are limited. In this issue of Cancer Cell, Zhou et al. demonstrate serplulimab plus chemotherapy as an effective first-line regimen to treat patients with advanced squamous NSCLC.

Reduced Tumor Volume and Increased Necrosis of Human Breast Tumor Xenograft in Mice Pretreated by a Cocktail of Three Specific Anti-HER2 scFvs

PURPOSE

We aimed to assess the effects of a cocktail comprising three specific anti- HER2 scFvs on breast tumor formation in a xenograft mouse model and to evaluate quantitative changes in the tumor using stereological analysis.

METHODS

Three specific anti-HER2 phage antibodies were produced from a scFv-library using phage display technology. The cell binding capacities of the antibodies were assessed via FACS analysis. Soluble forms of the antibodies were prepared by infecting HB2151-E. coli cells and purified using a centrifugal ultrafiltration method. The purification process was evaluated by SDSPAGE analysis. Two forms of scFv cocktails were prepared, soluble scFv and phage-scFv cocktail, which contained an equal amount/phage of each of the three antibodies. Inbred female BALB/c mice were pretreated with 5 and 20 mg/kg of the soluble scFv cocktail and 1011 phage-scFv cocktail/ kg. The mice were then injected with 2×106 SKBR-3 human breast cancer cells. Total tumor, inflammatory and non-inflammatory volumes were estimated using the Cavalieri principle after preparing photomicrograph slides.

RESULTS

The anti-HER2 scFvs showed significantly higher binding to SKBR-3 cells compared to the isotype control. SDS-PAGE analysis confirmed the high purification of the scFvs. Stereological analysis revealed that the group pretreated with 20 mg/kg of the soluble scFv cocktail exhibited the highest reductions in total tumor volume, non-inflammatory volume, and inflammatory volume, with reductions of 73%, 78%, and 72%, respectively, compared to PBS-pretreated mice (P-value < 0.0001). The volumetric ratio of necrotic tissue to total tumor volume increased by 2.2-fold and 2- fold in the 20 mg/kg of soluble scFv cocktail and phage-scFv cocktail groups, respectively, compared to the PBS-treated mice (P-value < 0.05).

CONCLUSION

Pre-treatment with a 20 mg/kg anti-HER2 scFv cocktail resulted in a significant reduction in tumor volume and increased necrotic area in a human breast cancer xenograft model, indicating the remarkable anti-tumor effect of the cocktail in vivo.

Efficacy and safety of first-line PD-1/PD-L1 inhibitor combinations for extensive-stage small-cell lung cancer: a Bayesian network meta-analysis

Objectives

Several randomized controlled trials (RCTs) indicated that first-line programmed cell death protein-1/death-ligand 1 inhibitors plus chemotherapy (PD-1/PD-L1 + chemo) led to survival benefits in extensive-stage small-cell lung cancer (ES-SCLC) compared with platinum-based chemotherapy. This study aims to identify the optimal PD-1/PD-L1 + chemo combination strategy.

Methods

We included RCTs comparing PD-1/ PD-L1 + chemo versus chemo alone in ES-SCLC. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and grade ⩾3 treatment-related adverse events were considered. Odds ratios (ORs), hazard ratios (HRs), and their 95% confidence intervals (CIs) were extracted.

Results

Six RCTs with 2600 patients were analyzed in this Bayesian network meta-analysis. Results showed that adding PD-1/PD-L1 inhibitors to chemotherapy led to significant benefits in OS (HR = 0.72, 95% CI: 0.66-0.79), PFS (HR = 0.69, 95% CI: 0.63-0.75), and ORR (OR = 1.32, 95% CI: 1.12-1.56), and no differences in toxicity were found (OR = 1.09, 95% CI: 0.92-1.30). Serplulimab plus chemotherapy was found to provide the best OS (HR = 0.63, 95% CI: 0.49-0.82), the best PFS (HR = 0.47, 95% CI: 0.38-0.59), and the best ORR (OR = 1.7, 95% CI: 1.15-2.53). Moreover, although there were no difference between PD-L1 + chemo and PD-1 + chemo regarding OS (HR = 0.99, 95% CI: 0.91-1.08) and ORR (OR = 1.27, 95% CI: 0.91-1.78), PD-1 + chemo showed a significant benefit in PFS (HR = 0.82, 95% CI: 0.68-0.98) compared with PD-L1 + chemo.

Conclusions

Serplulimab plus chemotherapy seems to be superior first-line immunotherapy combination for patients with ES-SCLC. PD-1 + chemo seems to outperform PD-L1 + chemo in PFS.

Development of a high-affinity anti-bovine PD-1 rabbit-bovine chimeric antibody using an efficient selection and large production system

Immune checkpoint molecules PD-1/PD-L1 cause T-cell exhaustion and contribute to disease progression in chronic infections of cattle. We established monoclonal antibodies (mAbs) that specifically inhibit the binding of bovine PD-1/PD-L1; however, conventional anti-PD-1 mAbs are not suitable as therapeutic agents because of their low binding affinity to antigen. In addition, their sensitivity for the detection of bovine PD-1 is low and their use for immunostaining PD-1 is limited. To address these issues, we established two anti-bovine PD-1 rabbit mAbs (1F10F1 and 4F5F2) and its chimeric form using bovine IgG1 (Boch1D10F1), which exhibit high binding affinity. One of the rabbit mAb 1D10F1 binds more strongly to bovine PD-1 compared with a conventional anti-PD-1 mAb (5D2) and exhibits marked inhibitory activity on the PD-1/PD-L1 interaction. In addition, PD-1 expression in bovine T cells could be detected with higher sensitivity by flow cytometry using 1D10F1. Furthermore, we established higher-producing cells of Boch1D10F1 and succeeded in the mass production of Boch1D10F1. Boch1D10F1 exhibited a similar binding affinity to bovine PD-1 and the inhibitory activity on PD-1/PD-L1 binding compared with 1D10F1. The immune activation by Boch1D10F1 was also confirmed by the enhancement of IFN-γ production. Finally, Boch1D10F1 was administered to bovine leukemia virus-infected cows to determine its antiviral effect. In conclusion, the high-affinity anti-PD-1 antibody developed in this study represents a powerful tool for detecting and inhibiting bovine PD-1 and is a candidate for PD-1-targeted immunotherapy in cattle.

Cost-effectiveness analysis of serplulimab as first-line treatment for advanced esophageal squamous cell carcinoma

Objective: To evaluate the cost-effectiveness of serplulimab as first-line treatment for patients with advanced esophageal squamous cell carcinoma from the perspective of the Chinese healthcare system. Materials & methods: A partitioned survival model was created to evaluate costs and health outcomes. The model's robustness was evaluated using one-way and probabilistic sensitivity analyses. Results: Serplulimab demonstrated an incremental cost-effectiveness ratio of $104,537.375/quality-adjusted life-year in the overall population group. Subgroup analysis showed that serplulimab had incremental cost-effectiveness ratios of $261,750.496/quality-adjusted life-year and $68,107.997/quality-adjusted life-year in the populations with PD-L1 1 ≤ combined positive score <10 and PD-L1 combined positive score ≥10, respectively. Conclusion: Incremental cost-effectiveness ratios of serplulimab therapy were found to exceed the willingness-to-pay threshold of $37,304.34. Thus, serplulimab is not cost-effective compared with chemotherapy as a first-line treatment for esophageal squamous cell carcinoma patients.

Advances in immune checkpoint inhibitors therapy for small cell lung cancer

BACKGROUND

As one of the most aggressive neuroendocrine tumors, small cell lung cancer (SCLC) has the most disappointing prognosis of all lung cancers. Although SCLC responds well to initial chemotherapy, the majority of patients experience disease recurrence within one year, and patient survival is poor. It is still necessary to explore the application of ICIs in SCLC since the beginning of the road to immunotherapy, which broke the 30-year treatment deadlock of SCLC.

METHODS

We searched PubMed, Web of Science, and Embase with search terms such as "SCLC", "ES-SCLC", "ICIs", and "ICBs", and categorized and summarized the relevant literature obtained, and we compiled the latest progress about the application of ICIs in SCLC.

RESULTS

We listed 14 clinical trials on ICIs, including 8 clinical trials on first-line SCLC treatment, 2 clinical trials on second-line SCLC treatment, 3 clinical trials on third-line SCLC treatment, and 1 clinical trial on SCLC maintenance treatment.

CONCLUSION

ICIs in combination with chemotherapy can improve OS in SCLC patients, but the extent to which SCLC patients can benefit from ICIs is limited, and ICIs' combination treatment strategies still need to be continuously explored.

Promise of dostarlimab in cancer therapy: Advancements and cross-talk considerations

In recent years, immunotherapy for cancer treatment using monoclonal antibodies has shown clinical success, particularly with programmed cell death protein 1 (PD-1) and its ligand programmed death-ligand 1 (PD-L1). Dostarlimab, an immune checkpoint inhibitor, interacts with adaptive immunity by binding to human PD-1, inhibiting PD-L1 and PD-L2 interactions, and cross-talk with adaptive immunity. Recent clinical trials have shown that dostarlimab is effective in treating mismatch repair deficiency (dMMR) in endometrial cancer patients, leading to its approval in the United States and the European Union in 2021. This article provides a comprehensive overview of dostarlimab, its therapeutic ability, and the different indications for which it is being used. Dostarlimab could serve as a potential alternative to many cancer treatments that frequently have severe consequences on patients' quality of life. Teaser The comprehensive story behind dostarlimab is how it cured all 18 cancer patients who took part in the experimental clinical trial, ultimately leading to its approval by the US FDA.

First-line serplulimab or placebo plus chemotherapy in PD-L1-positive esophageal squamous cell carcinoma: a randomized, double-blind phase 3 trial

First-line systemic therapeutic options for advanced esophageal squamous cell carcinoma (ESCC) are limited. In this multicenter, double-blind phase 3 trial, a total of 551 patients with previously untreated, locally advanced or metastatic ESCC and PD-L1 combined positive score of ≥1 were randomized (2:1) to receive serplulimab (an anti-PD-1 antibody; 3 mg/kg) or placebo (on day 1), plus cisplatin (50 mg/m2) (on day 1) and continuous infusion of 5-fluorouracil (1,200 mg/m2) (on days 1 and 2), once every 2 weeks. The study met the primary endpoints. At the prespecified final analysis of progression-free survival (PFS) assessed by the blinded independent radiological review committee, serplulimab plus chemotherapy significantly improved PFS compared with placebo plus chemotherapy (median PFS of 5.8 months and 5.3 months, respectively; hazard ratio, 0.60; 95% confidence interval, 0.48-0.75; P < 0.0001). At the prespecified interim analysis of overall survival (OS), serplulimab plus chemotherapy also significantly prolonged OS compared with placebo plus chemotherapy (median OS of 15.3 months and 11.8 months, respectively; hazard ratio, 0.68; 95% confidence interval, 0.53-0.87; P = 0.0020). Grade 3 or higher treatment-related adverse events occurred in 201 (53%) and 81 (48%) patients in the serplulimab plus chemotherapy group and the placebo plus chemotherapy group, respectively. Serplulimab plus chemotherapy administered every 2 weeks significantly improved PFS and OS in patients with previously untreated, PD-L1-positive advanced ESCC, with a manageable safety profile. This study is registered with ClinicalTrials.gov ( NCT03958890 ).

Advances in the structural characterization of complexes of therapeutic antibodies with PD-1 or PD-L1

Antibody-based immune checkpoint blockade (ICB)-based therapeutics have become effective clinical applications for cancers. Applications of monoclonal antibodies (mAbs) to de-activate the PD-1-PD-L1 pathway could effectively reverse the phenotype of depleted activated thymocytes (T cells) to recover their anti-tumoral activities. High-resolution structures of the complexes of the therapeutic monoclonal antibodies with PD-1 or PD-L1 have revealed the key inter-molecular interactions and provided valuable insights into the fundamental mechanisms by which these antibodies inhibit PD-L1-PD-1 binding. Each anti-PD-1 mAb exhibits a unique blockade mechanism, such as interference with large PD-1-PD-L1 contacting interfaces, steric hindrance by overlapping a small area of this site, or binding to an N-glycosylated site. In contrast, all therapeutic anti-PD-L1 mAbs bind to a similar area of PD-L1. Here, we summarized advances in the structural characterization of the complexes of commercial mAbs that target PD-1 or PD-L1. In particular, we focus on the unique characteristics of those mAb structures, epitopes, and blockade mechanisms. It is well known that the use of antibodies as anti-tumor drugs has increased recently and both PD-1 and PD-L1 have attracted substantial attention as target for antibodies derived from new technologies. By focusing on structural characterization, this review aims to aid the development of novel antibodies targeting PD-1 or PD-L1 in the future.

Hsa_hsa_circ_0081069 promotes the progression of colorectal cancer through sponging miR-665 and regulating E2F3 expression

BACKGROUND

Circular RNAs (circRNAs) have been implicated in the initiation and development of various cancers. This study explored the potential contribution of hsa_hsa_circ_0081069 in the progression of colorectal cancer (CRC).

METHODS

The gene expression was analyzed by qRT-PCR. Functional roles of hsa_circ_0081069 were examined by shRNA-mediated silencing using CCK-8 proliferation assay, Transwell migration and invasion assay, tube formation assay. The tumorigenesis and metastasis of CRC cells were assess in a xenograft mouse model.

RESULTS

Hsa_circ_0081069 was significantly upregulated in CRC tissues and cells. Hsa_circ_0081069 knockdown suppressed the proliferation, migration and invasion in CRC cells, as well as the angiogenesis. Silencing hsa_circ_0081069 also impaired the tumorigenesis of CRC cells in a xenograft mouse model. Furthermore, miR-665 was identified as an interacting partner of hsa_circ_0081069, which was negatively regulated by hsa_circ_0081069. miR-665 targeted the mRNA of E2F3 to suppress its expression. We further demonsatred that miR-665/E2F3 axis mediated the functional role of hsa_circ_0081069 in regulating the malignant phenotype of CRC cells.

CONCLUSIONS

Collectively, our study suggests that hsa_circ_0081069 could serve as a prognostic marker in progression of CRC. Targeting hsa_circ_0081069 and miR-665/E2F3 axis could serve as potential therapeutic strategies for CRC treatment.

Effect of First-Line Serplulimab vs Placebo Added to Chemotherapy on Survival in Patients With Extensive-Stage Small Cell Lung Cancer: The ASTRUM-005 Randomized Clinical Trial

IMPORTANCE

Programmed cell death ligand 1 inhibitors combined with chemotherapy has changed the approach to first-line treatment in patients with extensive-stage small cell lung cancer (SCLC). It remained unknown whether adding a programmed cell death 1 (PD-1) inhibitor to chemotherapy provided similar or better benefits in patients with extensive-stage SCLC, which would add evidence on the efficacy of checkpoint inhibitors in the treatment of extensive-stage SCLC.

OBJECTIVE

To evaluate the efficacy and adverse event profile of the PD-1 inhibitor serplulimab plus chemotherapy compared with placebo plus chemotherapy as first-line treatment in patients with extensive-stage SCLC.

DESIGN, SETTING, AND PARTICIPANTS

This international, double-blind, phase 3 randomized clinical trial (ASTRUM-005) enrolled patients at 114 hospital sites in 6 countries between September 12, 2019, and April 27, 2021. Of 894 patients who were screened, 585 with extensive-stage SCLC who had not previously received systemic therapy were randomized. Patients were followed up through October 22, 2021.

INTERVENTIONS

Patients were randomized 2:1 to receive either 4.5 mg/kg of serplulimab (n = 389) or placebo (n = 196) intravenously every 3 weeks. All patients received intravenous carboplatin and etoposide every 3 weeks for up to 12 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome was overall survival (prespecified significance threshold at the interim analysis, 2-sided P < .012). There were 13 secondary outcomes, including progression-free survival and adverse events.

RESULTS

Among the 585 patients who were randomized (mean age, 61.1 [SD, 8.67] years; 104 [17.8%] women), 246 (42.1%) completed the trial and 465 (79.5%) discontinued study treatment. All patients received study treatment and were included in the primary analyses. As of the data cutoff (October 22, 2021) for this interim analysis, the median duration of follow-up was 12.3 months (range, 0.2-24.8 months). The median overall survival was significantly longer in the serplulimab group (15.4 months [95% CI, 13.3 months-not evaluable]) than in the placebo group (10.9 months [95% CI, 10.0-14.3 months]) (hazard ratio, 0.63 [95% CI, 0.49-0.82]; P < .001). The median progression-free survival (assessed by an independent radiology review committee) also was longer in the serplulimab group (5.7 months [95% CI, 5.5-6.9 months]) than in the placebo group (4.3 months [95% CI, 4.2-4.5 months]) (hazard ratio, 0.48 [95% CI, 0.38-0.59]). Treatment-related adverse events that were grade 3 or higher occurred in 129 patients (33.2%) in the serplulimab group and in 54 patients (27.6%) in the placebo group.

CONCLUSIONS AND RELEVANCE

Among patients with previously untreated extensive-stage SCLC, serplulimab plus chemotherapy significantly improved overall survival compared with chemotherapy alone, supporting the use of serplulimab plus chemotherapy as the first-line treatment for this patient population.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04063163.

Serplulimab: First Approval

Serplulimab (^®) is an intravenously administered anti-PD-1 antibody being developed by Shanghai Henlius Biotech, Inc. for the treatment of solid tumours. Anti-PD-1 immunotherapies, such as serplulimab, can stimulate immune responses by relieving PD-1-related immunosuppression. Serplulimab received its first approval on 25 Mar 2022 in China for the treatment of adult patients with advanced unresectable or metastatic microsatellite instability-high (MSI-H) solid tumours that have failed to respond to previous standard treatments. This article summarizes the milestones in the development of serplulimab leading to this first approval in the treatment of MSI-H solid tumours in adults.