Results from a Meta-analysis of Combination of PD-1/PD-L1 and CTLA-4 Inhibitors in Malignant Cancer Patients: Does PD-L1 Matter?

Addition of immune checkpoint inhibitors to chemotherapy versus chemotherapy alone in patients with triple-negative breast cancer: A systematic review and meta-analysis

BACKGROUND

Triple-negative breast cancer (TNBC) is a relatively common malignant tumor with high mortality rates. There are limited treatment options and current therapy regimens often fall short of providing positive outcomes. The development of immune checkpoint inhibitors (ICIs) have provided a vital treatment option although efficacy has varied. Here, we review patient response to current TNBC treatment with and without the addition of ICIs.

METHODS

A systematic search of PubMed, Cochrane, and EMBASE library databases was done to search eligible studies published from their inception through April 3, 2022. The primary outcome indicators used were progression-free survival (PFS), overall survival (OS), pathological complete response rate (pCR) and objective remission rate (ORR), while adverse events (AEs) were also analyzed. Publication bias and sensitivity analyses and were performed to evaluate the quality of assessment.

RESULTS

Overall, the meta-analysis looked at seven randomized controlled trials (RCTs) that included 4631 patients with TNBC. Results showed an improvement in PFS for patients receiving ICI in addition to chemotherapy (CT) in both the intent-to-treat (ITT) population and PD-L1 positive patients. Increased pCR rates were observed in all patients irrespective of PD-L1 status as well as increased ORR in the ITT which was more notable in PD-L1 positive subjects. While significant improvement in OS was observed only in PD-L1 positive individuals, the use of ICIs plus CT resulted in severe adverse reactions, specifically immune-related.

CONCLUSIONS

This study supports the increased efficacy of ICIs in combination with CT compared to CT alone in patients with TNBC, with the most notable benefit observed in PD-L1 positive patients. However, combination therapy increases the risk of adverse reactions which warrants further investigation.

Systemic Therapy in Advanced Hepatocellular Carcinoma: Patient Selection and Key Considerations

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality worldwide. Most patients with HCC have advanced disease at initial diagnosis, and sorafenib has been the only systemic treatment option for more than a decade in patients with advanced, unresectable HCC. However, there has been a dramatic change in the treatment algorithm in the last several years, given new drug approvals in the field. Most importantly, the combination of atezolizumab and bevacizumab has demonstrated clinically meaningful benefits in terms of response rate, progression-free survival, and overall survival compared to sorafenib in the first-line setting. Recently a phase III trial showed that the combination of durvalumab with a single dose of tremelimumab improved overall survival compared to sorafenib, while durvalumab monotherapy was found to be noninferior to sorafenib, making it an attractive alternative single agent in selected patient populations. As immunotherapy makes its way into the therapeutic landscape of HCC, other novel targeted therapies, such as lenvatinib, cabozantinib, ramucirumab, and regorafenib, have also been approved by regulatory authorities for treatment of advanced, unresectable HCC. This review article focuses on the first-line systemic treatment options for HCC while addressing some of the most important questions aimed at optimization of HCC treatment.

The Features of Immune Checkpoint Gene Regulation by microRNA in Cancer

Currently, the search for new promising tools of immunotherapy continues. In this regard, microRNAs (miRNAs) that influence immune checkpoint (IC) gene expression in tumor and T-cells and may be important regulators of immune cells are considered. MiRNAs regulate gene expression by blocking mRNA translation. An important feature of miRNA is its ability to affect the expression of several genes simultaneously, which corresponds to the trend toward the use of combination therapy. The article provides a list of miRNAs acting simultaneously on several ICs and miRNAs that, in addition to IC, can regulate the expression of targeted therapy genes. There is dependence of miRNA interactions with IC genes on the type of cancer. The analysis of the accumulated data demonstrates that only about 14% (95% CI: 9.8–20.1%) of the studied miRNAs regulate the expression of specific IC in more than one type of cancer. That is, there is tumor specificity in the miRNA action on ICs. A number of miRNAs demonstrated high efficiency in vitro and in vivo. This indicates the potential of miRNAs as promising agents for cancer immunotherapy. Additional studies of the miRNA–gene interaction features and the search for an optimal miRNA mimic structure are necessary.

Biomarkers and 3D models predicting response to immune checkpoint blockade in head and neck cancer (Review)

Immunotherapy has evolved into a powerful tool in the fight against a number of types of cancer, including head and neck squamous cell carcinomas (HNSCC). Although checkpoint inhibition (CPI) has definitely enriched the treatment options for advanced stage HNSCC during the past decade, the percentage of patients responding to treatment is widely varying between 14-32% in second-line setting in recurrent or metastatic HNSCC with a sporadic durability. Clinical response and, consecutively, treatment success remain unpredictable in most of the cases. One potential factor is the expression of target molecules of the tumor allowing cancer cells to acquire therapy resistance mechanisms. Accordingly, analyzing and modeling the complexity of the tumor microenvironment (TME) is key to i) stratify subgroups of patients most likely to respond to CPI and ii) to define new combinatorial treatment regimens. Particularly in a heterogeneous disease such as HNSCC, thoroughly studying the interactions and crosstalking between tumor and TME cells is one of the biggest challenges. Sophisticated 3D models are therefore urgently needed to be able to validate such basic science hypotheses and to test novel immuno-oncologic treatment regimens in consideration of the individual biology of each tumor. The present review will first summarize recent findings on immunotherapy, predictive biomarkers, the role of the TME and signaling cascades eliciting during CPI. Second, it will highlight the significance of current promising approaches to establish HNSCC 3D models for new immunotherapies. The results are encouraging and indicate that data obtained from patient-specific tumors in a dish might be finally translated into personalized immuno-oncology.

PD-L1/PD-1 and CTLA-4 Expression in Equine Penile Squamous Cell Carcinomas

In horses, penile squamous cell carcinomas (epSCCs) are among the most common cutaneous neoplastic lesions. These tumors usually arise in benign lesions such as viral plaques and papillomas frequently induced by Equus caballus papillomavirus type 2 (EcPV2) infection. In the last decade, the introduction of immune checkpoint inhibitors (ICI) for the treatment of human cancers has demonstrated promising results. Among the most commonly targeted pathways, there is PD-1/PD-L1 and CTLA-4. The aim of this study is to investigate the expression of the PD-1/PD-L1 pathway and CTLA-4 in the tumor microenvironment of epSCCs to assess the feasibility of an immunotherapeutic approach. Twenty equine epithelial tumors were retrospectively selected and submitted to RT-qPCR for PD-1 and PD-L1 genes. After testing antibodies cross-reactivity by western blotting, immunohistochemistry for PD-L1 and CTLA-4 was performed. Results from RT-qPCR demonstrated that 3/20 cases expressed the PD-L1 gene, whereas the PD-1 gene was not detected. Immunohistochemical positivity for PD-L1 was found only in one case. CTLA-4-positive cells were observe in all cases but were few (Mdn = 4.8; IQR = 2.3-7.1 cells/HPF). In this study group, PD-1/PD-L1 and CTLA-4 do not appear to be highly expressed and therefore the use of ICI in epSCCs may not have promising rates of response.