Phase 2 study of ipilimumab, nivolumab, and tocilizumab combined with stereotactic body radiotherapy in patients with refractory pancreatic cancer (TRIPLE-R)

Programmed cell death 1 inhibitor sintilimab plus concurrent chemoradiotherapy for locally advanced pancreatic adenocarcinoma

BACKGROUND

Pancreatic adenocarcinoma, a malignancy that arises in the cells of the pancreas, is a devastating disease with unclear etiology and often poor prognosis. Locally advanced pancreatic cancer, a stage where the tumor has grown significantly but has not yet spread to distant organs, presents unique challenges in treatment. This article aims to discuss the current strategies, challenges, and future directions in the management of locally advanced pancreatic adenocarcinoma (LAPC).

AIM

To investigate the feasibility and efficacy of programmed cell death 1 (PD-1) inhibitor sintilimab plus concurrent chemoradiotherapy for LAPC.

METHODS

Eligible patients had LAPC, an Eastern cooperative oncology group performance status of 0 or 1, adequate organ and marrow functions, and no prior anticancer therapy. In the observation group, participants received intravenous sintilimab 200 mg once every 3 wk, and received concurrent chemoradiotherapy (concurrent conventional fractionated radiotherapy with doses planning target volume 50.4 Gy and gross tumor volume 60 Gy in 28 fractions and oral S-1 40 mg/m2 twice daily on days 1-14 of a 21-d cycle and intravenous gemcitabine 1000 mg/m2 on days 1 and 8 of a 21-d cycle for eight cycles until disease progression, death, or unacceptable toxicity). In the control group, participants only received concurrent chemoradiotherapy. From April 2020 to November 2021, 64 participants were finally enrolled with 34 in the observation group and 30 in the control group.

RESULTS

Thirty-four patients completed the scheduled course of chemoradiotherapy, while 32 (94.1%) received sintilimab plus concurrent chemoradiotherapy with 2 patients discontinuing sintilimab in the observation group. Thirty patients completed the scheduled course of chemoradiotherapy in the control group. Based on the Response Evaluation Criteria in Solid Tumors guidelines, the analysis of the observation group revealed that a partial response was observed in 11 patients (32.4%), stable disease was evident in 19 patients (55.9%), and 4 patients (11.8%) experienced progressive disease; a partial response was observed in 6 (20.0%) patients, stable disease in 18 (60%), and progressive disease in 6 (20%) in the control group. The major toxic effects were leukopenia and nausea. The incidence of severe adverse events (AEs) (grade 3 or 4) was 26.5% (9/34) in the observation group and 23.3% (7/30) in the control group. There were no treatment-related deaths. The observation group demonstrated a significantly longer median overall survival (22.1 mo compared to 15.8 mo) (P < 0.05) and progression-free survival (12.2 mo vs 10.1 mo) (P < 0.05) in comparison to the control group. The occurrence of severe AEs did not exhibit a statistically significant difference between the observation group and the control group (P > 0.05).

CONCLUSION

Sintilimab plus concurrent chemoradiotherapy was effective and safe for LAPC patients, and warrants further investigation.

Radiotherapy and immunology

The majority of cancer patients receive radiotherapy during the course of treatment, delivered with curative intent for local tumor control or as part of a multimodality regimen aimed at eliminating distant metastasis. A major focus of research has been DNA damage; however, in the past two decades, emphasis has shifted to the important role the immune system plays in radiotherapy-induced anti-tumor effects. Radiotherapy reprograms the tumor microenvironment, triggering DNA and RNA sensing cascades that activate innate immunity and ultimately enhance adaptive immunity. In opposition, radiotherapy also induces suppression of anti-tumor immunity, including recruitment of regulatory T cells, myeloid-derived suppressor cells, and suppressive macrophages. The balance of pro- and anti-tumor immunity is regulated in part by radiotherapy-induced chemokines and cytokines. Microbiota can also influence radiotherapy outcomes and is under clinical investigation. Blockade of the PD-1/PD-L1 axis and CTLA-4 has been extensively investigated in combination with radiotherapy; we include a review of clinical trials involving inhibition of these immune checkpoints and radiotherapy.

Interleukin-6 serves as a critical factor in various cancer progression and therapy

Interleukin-6 (IL-6), a pro-inflammatory cytokine, plays a crucial role in host immune defense and acute stress responses. Moreover, it modulates various cellular processes, including proliferation, apoptosis, angiogenesis, and differentiation. These effects are facilitated by various signaling pathways, particularly the signal transducer and activator of transcription 3 (STAT3) and Janus kinase 2 (JAK2). However, excessive IL-6 production and dysregulated signaling are associated with various cancers, promoting tumorigenesis by influencing all cancer hallmarks, such as apoptosis, survival, proliferation, angiogenesis, invasiveness, metastasis, and notably, metabolism. Emerging evidence indicates that selective inhibition of the IL-6 signaling pathway yields therapeutic benefits across diverse malignancies, such as multiple myeloma, prostate, colorectal, renal, ovarian, and lung cancers. Targeting key components of IL-6 signaling, such as IL-6Rs, gp130, STAT3, and JAK via monoclonal antibodies (mAbs) or small molecules, is a heavily researched approach in preclinical cancer studies. The purpose of this study is to offer an overview of the role of IL-6 and its signaling pathway in various cancer types. Furthermore, we discussed current preclinical and clinical studies focusing on targeting IL-6 signaling as a therapeutic strategy for various types of cancer.

Cellular collusion: cracking the code of immunosuppression and chemo resistance in PDAC

Despite the efforts, pancreatic ductal adenocarcinoma (PDAC) is still highly lethal. Therapeutic challenges reside in late diagnosis and establishment of peculiar tumor microenvironment (TME) supporting tumor outgrowth. This stromal landscape is highly heterogeneous between patients and even in the same patient. The organization of functional sub-TME with different cellular compositions provides evolutive advantages and sustains therapeutic resistance. Tumor progressively establishes a TME that can suit its own needs, including proliferation, stemness and invasion. Cancer-associated fibroblasts and immune cells, the main non-neoplastic cellular TME components, follow soluble factors-mediated neoplastic instructions and synergize to promote chemoresistance and immune surveillance destruction. Unveiling heterotypic stromal-neoplastic interactions is thus pivotal to breaking this synergism and promoting the reprogramming of the TME toward an anti-tumor milieu, improving thus the efficacy of conventional and immune-based therapies. We underscore recent advances in the characterization of immune and fibroblast stromal components supporting or dampening pancreatic cancer progression, as well as novel multi-omic technologies improving the current knowledge of PDAC biology. Finally, we put into context how the clinic will translate the acquired knowledge to design new-generation clinical trials with the final aim of improving the outcome of PDAC patients.

A new era of immune therapeutics for pancreatic cancer: Monoclonal antibodies paving the way

Pancreatic cancer, particularly pancreatic ductal adenocarcinoma, remains a devastating disease with a dismal prognosis and limited survival rates. Despite various drug treatments and regimens showing promise in managing the disease, the clinical outcomes have not significantly improved. Immunotherapy however, has become a forefront area in pancreatic cancer treatment. This approach comprises a range of agents, including small molecule drugs, antibodies, combination therapies, and vaccines. In the last 5-8 years, there has been an upsurge of research into the use of monoclonal antibodies to block receptors on cancer or immune cells, revolutionising cancer treatment and management. Several targets have been identified and studied, with the most encouraging noted in relation to checkpoint markers, namely, antibodies targeting anti-programmed cell death 1 (PD-1) and its receptor PD-L1. Herein, we present the clinical developments in immunotherapy in the last 5 years especially those which have been tested in humans against pancreatic cancer.

Clinical immunotherapy in pancreatic cancer

Pancreatic cancer remains a challenging disease with limited treatment options, resulting in high mortality rates. The predominant approach to managing pancreatic cancer patients continues to be systemic cytotoxic chemotherapy. Despite substantial advancements in immunotherapy strategies for various cancers, their clinical utility in pancreatic cancer has proven less effective and durable. Whether administered as monotherapy, employing immune checkpoint inhibitors, tumor vaccines, chimeric antigen receptors T cells, or in combination with conventional chemoradiotherapy, the clinical outcomes remain underwhelming. Extensive preclinical experiments and clinical trials in the realm of pancreatic cancer have provided valuable insights into the complexities of immunotherapy. Chief among the hurdles are the immunosuppressive tumor microenvironment, limited immunogenicity, and the inherent heterogeneity of pancreatic cancer. In this comprehensive review, we provide an overview and critical analysis of current clinical immunotherapy strategies for pancreatic cancer, emphasizing their endeavors to overcome immunotherapy resistance. Particular focus is placed on strategies aimed at reshaping the immunosuppressive microenvironment and enhancing T cell-mediated tumor cell killing. Ultimately, through deeper elucidation of the underlying pathogenic mechanisms of pancreatic cancer and the refinement of therapeutic approaches, we anticipate breakthroughs that will pave the way for more effective treatments in this challenging disease.

Tumor immune microenvironment-based therapies in pancreatic ductal adenocarcinoma: time to update the concept

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid tumors. The tumor immune microenvironment (TIME) formed by interactions among cancer cells, immune cells, cancer-associated fibroblasts (CAF), and extracellular matrix (ECM) components drives PDAC in a more immunosuppressive direction: this is a major cause of therapy resistance and poor prognosis. In recent years, research has advanced our understanding of the signaling mechanism by which TIME components interact with the tumor and the evolution of immunophenotyping. Through revolutionary technologies such as single-cell sequencing, we have gone from simply classifying PDACs as "cold" and "hot" to a more comprehensive approach of immunophenotyping that considers all the cells and matrix components. This is key to improving the clinical efficacy of PDAC treatments. In this review, we elaborate on various TIME components in PDAC, the signaling mechanisms underlying their interactions, and the latest research into PDAC immunophenotyping. A deep understanding of these network interactions will contribute to the effective combination of TIME-based therapeutic approaches, such as immune checkpoint inhibitors (ICI), adoptive cell therapy, therapies targeting myeloid cells, CAF reprogramming, and stromal normalization. By selecting the appropriate integrated therapies based on precise immunophenotyping, significant advances in the future treatment of PDAC are possible.

An overview of up-and-coming immune checkpoint inhibitors for pancreatic cancer

INTRODUCTION

Immune checkpoint inhibitors (ICIs) targeting programmed cell death protein-1 (PD-1/PD-L1) pathway as well as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) have demonstrated substantial potential in several malignancies. Pancreatic adenocarcinoma (PC) still carries a high mortality despite tremendous advances in the anti-cancer arsenal.

AREAS COVERED

In this review, we discuss completed and ongoing studies on various ICIs in PC. ICIs have not yielded significant benefits as monotherapy. However, the combination with currently utilized therapies as well as with several other newer forms of therapy has delineated encouraging results. Larger trials are currently underway to definitively characterize the utility of ICIs in the treatment algorithm of PC. ICIs are approved for cancers with mismatch repair deficiency (dMMR) or microsatellite instability-high tumors (MSI-H) as a tumor-agnostic treatment strategy usually referred to as hot tumors.

EXPERT OPINION

Studies evaluating different drugs to transform the tumor microenvironment (TME) from 'cold' to 'hot' have not shown promise in PC. There still needs to be more prospective trials evaluating the efficacy of the combination of ICIs with different therapeutic modalities in PC that can augment the immunogenic potential of those 'cold' tumors. Exploratory biomarker analysis may help us identify those subsets of PC patients who may particularly benefit from ICIs.

Comparison of the effectiveness of integrative immunomodulatory treatments and conventional therapies on the survival of selected gastrointestinal cancer patients

In the last decade, the use of immunomodulating treatments (IMT) at integrative oncology providers (IOP) increased. IMTs are used to modulate the tumor microenvironment, which might lead to increased response-to-treatment, and the indication of immune checkpoint inhibitors might also be widened. The efficacy and safety of IMTs in advanced/metastatic gastrointestinal cancers were compared with conventional chemo(radio)therapy (CT). 21 colorectal- (CRC), 14 pancreatic- (PC), 5 cholangiocellular- (CCC), 5 gastric- (GC) and 4 esophageal cancer (EC) patients received IMT. IMT and CT were compared in CRC and PC. CT was administered at an academic oncology center. After the initiation of IMT, a median survival of ~ 20 (CRC, PC and EC) and ~ 10 months (CCC and GC) was observed. Of the IMTs, locoregional modulated electro-hyperthermia had the most positive effect on overall survival (HR: 0.3055; P = 0.0260), while fever-inducing interleukin-2, and low-dose ipilimumab showed a positive tendency. IMT was superior to CT in PC (HR: 0.1974; P = 0.0013), while modest effect was detected in CRC (HR: 0.7797; P = 0.4710). When the whole study population was analyzed, IMTs showed minimal effect on patient survival, still CT had the greatest effect if introduced as early as possible (HR: 0.0624; P < 0.0001). The integrative IMTs in the presented form have mild impact on gastrointestinal cancer patients' survival, however, we observed its benefit in PC, which warrants further investigations.

The Role of Immune Checkpoint Inhibitors in Metastatic Pancreatic Cancer: Current State and Outlook

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest tumors, characterized by its aggressive tumor biology and poor prognosis. While immune checkpoint inhibitors (ICIs) play a major part in the treatment algorithm of various solid tumors, there is still no evidence of clinical benefit from ICI in patients with metastatic PDAC (mPDAC). This might be due to several reasons, such as the inherent low immunogenicity of pancreatic cancer, the dense stroma-rich tumor microenvironment that precludes an efficient migration of antitumoral effector T cells to the cancer cells, and the increased proportion of immunosuppressive immune cells, such as regulatory T cells (Tregs), cancer-associated fibroblasts (CAFs), and myeloid-derived suppressor cells (MDSCs), facilitating tumor growth and invasion. In this review, we provide an overview of the current state of ICIs in mPDAC, report on the biological rationale to implement ICIs into the treatment strategy of pancreatic cancer, and discuss preclinical studies and clinical trials in this field. Additionally, we shed light on the challenges of implementing ICIs into the treatment strategy of PDAC and discuss potential future directions.