Near Complete Pathologic Response to PD-1 Inhibitor and Radiotherapy in a Patient with Locally Advanced Pancreatic Ductal Adenocarcinoma

Overcoming the limitations of immunotherapy in pancreatic ductal adenocarcinoma: Combining radiotherapy and metabolic targeting therapy

As a novel anticancer therapy, immunotherapy has demonstrated robust efficacy against a few solid tumors but poor efficacy against pancreatic ductal adenocarcinoma (PDAC). This poor outcome is primarily attributable to the intrinsic cancer cell resistance and T-cell exhaustion, which is also the reason for the failure of conventional therapy. The present review summarizes the current PDAC immunotherapy avenues and the underlying resistance mechanisms. Then, the review discusses synergistic combination therapies, such as radiotherapy (RT) and metabolic targeting. Research suggests that RT boosts the antigen of PDAC, which facilitates the anti-tumor immune cell infiltration and exerts function. Metabolic reprogramming contributes to restoring the exhausted T cell function. The current review will help in tailoring combination regimens to enhance the efficacy of immunotherapy. In addition, it will help provide new approaches to address the limitations of the immunosuppressive tumor microenvironment (TME) by examining the relationship among immunotherapy, RT, and metabolism targeting therapy in PDAC.

Advances in Immunotherapeutics in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) accounts for up to 95% of all pancreatic cancer cases and is the seventh-leading cause of cancer death. Poor prognosis is a result of late presentation, a lack of screening tests and the fact some patients develop resistance to chemotherapy and radiotherapy. Novel therapies like immunotherapeutics have been of recent interest in pancreatic cancer. However, this field remains in its infancy with much to unravel. Immunotherapy and other targeted therapies have yet to yield significant progress in treating PDAC, primarily due to our limited understanding of the disease immune mechanisms and its intricate interactions with the tumour microenvironment (TME). In this review we provide an overview of current novel immunotherapies which have been studied in the field of pancreatic cancer. We discuss their mechanisms, evidence available in pancreatic cancer as well as the limitations of such therapies. We showcase the potential role of combining novel therapies in PDAC, postulate their potential clinical implications and the hurdles associated with their use in PDAC. Therapies discussed with include programmed death checkpoint inhibitors, Cytotoxic T-lymphocyte-associated protein 4, Chimeric Antigen Receptor-T cell therapy, oncolytic viral therapy and vaccine therapies including KRAS vaccines, Telomerase vaccines, Gastrin Vaccines, Survivin-targeting vaccines, Heat-shock protein (HSP) peptide complex-based vaccines, MUC-1 targeting vaccines, Listeria based vaccines and Dendritic cell-based vaccines.

Neoadjuvant Immunotherapy for Localized Pancreatic Cancer: Challenges and Early Results

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease due to its late presentation and tendency to recur early even after optimal surgical resection. Currently, there are limited options for effective systemic therapy. In addition, PDAC typically generates an immune-suppressive tumor microenvironment; trials of immunotherapy in metastatic PDAC have yielded disappointing results. There is considerable interest in using immunotherapy approaches in the neoadjuvant setting in order to prime the immune system to detect and prevent micrometastatic disease and recurrence. A scoping review was conducted to identify published and ongoing trials utilizing preoperative immunotherapy. In total, 9 published trials and 27 ongoing trials were identified. The published trials included neoadjuvant immune checkpoint inhibitors, cancer vaccines, and other immune-modulating agents that target mechanisms distinct from that of immune checkpoint inhibition. Most of these are early phase trials which suggest improvements in disease-free and overall survival when combined with standard neoadjuvant therapy. Ongoing trials are exploring various combinations of these agents with each other and with chemotherapy and/or radiation. Rational combination immunotherapy in addition to standard neoadjuvant therapy has the potential to improve outcomes in PDAC, but further clinical trials are needed, particularly those which utilize an adaptive trial design.

New Treatment Options in Metastatic Pancreatic Cancer

Pancreatic cancer (PC) is the seventh leading cause of cancer death across the world. Poor prognosis of PC is associated with several factors, such as diagnosis at an advanced stage, early distant metastases, and remarkable resistance to most conventional treatment options. The pathogenesis of PC seems to be significantly more complicated than originally assumed, and findings in other solid tumours cannot be extrapolated to this malignancy. To develop effective treatment schemes prolonging patient survival, a multidirectional approach encompassing different aspects of the cancer is needed. Particular directions have been established; however, further studies bringing them all together and connecting the strengths of each therapy are needed. This review summarises the current literature and provides an overview of new or emerging therapeutic strategies for the more effective management of metastatic PC.

PD-1 blockade plus chemoradiotherapy as preoperative therapy for patients with BRPC/LAPC: A biomolecular exploratory, phase II trial

This is a phase II study of PD-1 blockade plus chemoradiotherapy as preoperative therapy for patients with locally advanced or borderline resectable pancreatic cancer (LAPC or BRPC, respectively). Twenty-nine patients are enrolled in the study. The objective response rate (ORR) is 60%, and the R0 resection rate is 90% (9/10). The 12-month progression-free survival (PFS) rate and 12-month overall survival (OS) rate are 64% and 72%, respectively. Grade 3 or higher adverse events are anemia (8%), thrombocytopenia (8%), and jaundice (8%). Circulating tumor DNA analysis reveals that patients with a >50% decline in maximal somatic variant allelic frequency (maxVAF) between the first clinical evaluation and baseline have a longer survival outcome and a higher response rate and surgical rate than those who are not. PD-1 blockade plus chemoradiotherapy as preoperative therapy displays promising antitumor activity, and multiomics potential predictive biomarkers are identified and warrant further verification.

Case Report: Pathologic Complete Response to Induction Therapy in a Patient With Potentially Resectable Pancreatic Cancer

Immune monotherapy does not appear to work in patients with pancreatic cancer so far. We are conducting a clinical trial that combines programmed cell death protein-1 (PD-1) inhibitor with chemotherapy and concurrent radiotherapy as induction therapy for patients with locally advanced pancreatic cancer (LAPC) and borderline resectable pancreatic cancer (BRPC). Here, we report a case with a pathologic complete response (pCR) and no postoperative complications after the induction therapy. The patient received four cycles of induction therapy and achieved a partial response (PR) with a significant decline of tumor marker carbohydrate antigen 19-9 (CA19-9). Also, peripheral blood samples were collected during the treatment to investigate serial circulating tumor DNA (ctDNA) dynamic changes in predicting the tumor response and outcomes in patients. Our result suggested that PD-1 blockade plus chemotherapy and concurrent radiotherapy is a promising mode as induction therapy for patients with potentially resectable pancreatic cancer. In this case, serial ctDNA alterations accurately provide a comprehensive outlook of the tumor status and monitor the response to the therapy, as validated by standard imaging.

Combination therapy for pancreatic cancer: anti-PD-(L)1-based strategy

Mortality associated with pancreatic cancer is among the highest of all malignancies, with a 5-year overall survival of 5-10%. Immunotherapy, represented by the blocking antibodies against programmed cell death protein 1 or its ligand 1 (anti-PD-(L)1), has achieved remarkable success in a number of malignancies. However, due to the immune-suppressive tumor microenvironment, the therapeutic efficacy of anti-PD-(L)1 in pancreatic cancer is far from expectation. To address such a fundamental issue, chemotherapy, radiotherapy, targeted therapy and even immunotherapy itself, have individually been attempted to combine with anti-PD-(L)1 in preclinical and clinical investigation. This review, with a particular focus on pancreatic cancer therapy, collects current anti-PD-(L)1-based combination strategy, highlights potential adverse effects of accumulative combination, and further points out future direction in optimization of combination, including targeting post-translational modification of PD-(L)1 and improving precision of treatment.

First-Line Immunochemotherapy Versus Palliative Chemotherapy Plus Definitive Radiation Therapy for de novo Metastatic Nasopharyngeal Carcinoma: A Matched Cohort Study

BACKGROUND

The combined use of immune checkpoint inhibitors (ICIs) with palliative chemotherapy (PCT) is a promising first-line treatment for de novo metastatic nasopharyngeal carcinoma (mNPC). However, the efficacy of ICIs with PCT vs PCT with definitive radiation therapy (DRT) remain unclear.

METHODS

Patients with mNPC who received first-line immunochemotherapy (ICI + PCT) or PCT + DRT were included. Propensity score matching (PSM) was applied to balance potential confounders between patients who did and did not undergo DRT (at a ratio of 1:1). Progression free survival (PFS) and overall survival (OS) were compared between the 2 groups using a log-rank test and Cox proportional hazard model.

RESULTS

Among all participants, 149 received ICI + PCT. After PSM, 149 patients were included in the PCT + DRT group. First-line immunochemotherapy was associated with significantly improved PFS (median 9.0 months vs 12.0 months, P < .001) and OS (median 12.5 months vs 19.9 months, P < .001). Subgroup analysis revealed that tumor response to immunochemotherapy, metastatic organs, and number of metastatic sites potentially affected the efficacy of DRT after first-line immunochemotherapy.

CONCLUSION

Compared with PCT + DRT, first-line immunochemotherapy was associated with improved PFS and OS in patients with mNPC but not in patients with unfavorable tumor response and metastasis involving the liver, distant nodes, or multiple sites.