Journal of Clinical Trials
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A Multistrike Evolutionary Oncology Strategy for Locally Advanced Pancreatic Cancer: A Phase 1 Trial of Standard-of-Care Plus Irreversible Electroporation and Pembrolizumab Immunotherapy

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Introduction

Pancreatic Ductal Adenocarcinoma (PDAC) is a highly lethal malignancy with limited therapeutic options, particularly for patients with locally advanced disease [1]. Novels therapies are urgently needed because pancreatic cancer is projected to become the second leading cause of cancer-related deaths in the United States by 2030 [2].

Despite advances in CHT, RT and Chemoradiation Therapy (CRT), patients with unresectable LAPC have shown poor median Overall Survival (OS) of 6 to 11 months in most prospective clinical trials. No Phase 3 prospective randomized clinical trial supports any specific treatment strategy for patients with LAPC. The current standard of care is based on consensus guidelines from leading authorities in oncology, such as the National Cancer Care Network (NCCN) [3]. The most common first-line treatment for LAPC is induction chemotherapy, usually followed by CRT, hypofractionated RT, or stereotactic body radiation therapy [4]. Induction CHT is usually Folinic acid, Fluorouracil, Irinotecan, and Oxaliplatin (FOLFIRINOX) or a modified FOLFIRINOX regimen [5]. For patients with marginal performance status, the CHT regimen is gemcitabine plus albumin-bound paclitaxel. The NCCN guidelines indicate 4 subsequent therapy options for patients with LAPC who have good performance status following first-line therapy: 1) Consider resection, if feasible, 2) Observe patients, 3) Continue systemic therapy and 4) Perform clinical trial [3].

Immunotherapy (IO) has revolutionized cancer treatment, demonstrating impressive results in various malignancies, such as melanoma and lung cancer [6,7]. However, pancreatic cancer has proven highly resistant to IO, primarily because of its immunosuppressive TME and cold tumor phenotype, characterized by a lack of immune-cell infiltration [8,9]. The TME in PDAC is highly complex and heterogeneous, consisting of a dense fibroinflammatory stroma with abundant extracellular matrix components, immunosuppressive cell populations, and limited vascularization [10,11]. This environment not only provides physical barriers to immune-cell infiltration but also actively suppresses antitumor immune responses through various mechanisms, such as recruiting regulatory T cells and myeloid-derived suppressor cells, secreting immunosuppressive cytokines, and upregulating immune checkpoint molecules [12,13]. In addition to the dense extracellular matrix and immunosuppressive cell populations, other factors contributing to the complexity of the TME include hypoxia and nutrient deprivation and the presence of various signaling molecules that can promote tumor growth and immune evasion [14,15]. These factors collectively contribute to forming a highly immunosuppressive TME that protects pancreatic cancer cells from immune-mediated destruction.

Several tumor-directed therapies have been developed to target the immunosuppressive TME and improve the efficacy of IO in pancreatic cancer. These approaches include RT, IRE and ultrasound- based modalities, each with its own challenges and limitations [16-18]. Locally ablative therapies, like IRE and stereotactic body RT, have been proposed to overcome these challenges by disrupting the stromal matrix and promoting immune-cell infiltration, effectively converting cold tumors into hot ones [19,20].

IRE uses high-voltage, short, direct-current electrical pulses to produce an electric field that induces electroporation on cells and creates nanoscale defects (permanent pores) in cellular membranes, resulting in loss of homeostasis and subsequent cell death [21-23]. The preliminary reports of the experience of IRE in patients with unresectable LAPC show encouraging results [24,25]. A recent systemic review of IRE in LAPC included 15 studies involving 691 patients [26]. Eight of the 15 studies were retrospective single- center studies, and the remaining 7 were prospective single-center or multicenter studies. The induction treatment varied, with 70% receiving induction CHT and only 20% to 50% receiving radiation therapy; the median OS in the combined cohort varied from 10 to 27 months. A recently initiated pivotal Phase 3 trial is a randomized control trial of FOLFIRINOX alone vs. FOLFIRINOX plus IRE in LAPC (NCT#03899636) [27].

We hypothesize that outcomes for patients with LAPC can be improved by using IRE as a strategy to alter the TME of PDAC, so that the LAPC will be more responsive to systemic IO. This sequential therapy approach is supported by dynamic evolutionary extinction models, which suggest that the timing of a second strike is a critical factor in inducing a lasting change within the TME [28]. This strategy uses the theoretical framework of evolutionary dynamics, using an Anthropocene extinction model. We predict that the IRE will alter the cold PDAC TME to hot, thereby making it more responsive to checkpoint inhibitor therapy. By administering IRE and Immune Checkpoint Inhibitor (ICI) therapy after first-line therapy (i.e., CHT followed by RT), we aim to target residual tumor cells that have survived initial treatment, potentially increasing the likelihood of a durable response.

This strategy uses the theoretical framework of evolutionary dynamics, with an Anthropocene extinction model. Anthropocene extinction events demonstrate that populations often follow one of 2 patterns after experiencing an initial insult. These populations enter what is referred to by academics as an “extinction vortex.” They then either continue diminishing to a point when they cannot recover and face eventual extinction, or they rebound because they are inherently resistant (or develop resistance) against the initial insult. Thus, a window exists after an initial insult (first strike) during which a second intervention or another insult (second strike) may be used to push a population to complete eradication, ergo, complete extinction. However, for the second strike to be effective, it often cannot rely upon the same strategy as the first strike, because of selection pressure. Instead, an alternative strategy that can cause an entirely different form of evolutionary pressure must be applied. This concept can be applied to treating cancer and to the dynamics of adjuvant therapy. Therefore, in this clinical trial, we propose a novel multimodal strategy informed by dynamic evolutionary extinction models of first-line CHT and RT followed by sequentially administered IRE and IO with pembrolizumab for patients with LAPC who have good performance status and are not candidates for surgical resection.

Materials and Methods

Ethics approval

The study is approved by the Institutional Review Board (IRB) of H. Lee Moffitt Cancer Center and Research Institute (MCC) (MCC Study No. MCC# 22325, Advarra IRB #Pro00075545). Informed consent will be obtained from the participants and/or legal guardians. The trial is registered at the US NIH (ClinicalTrials.gov) as #NCT06378047. The current protocol is version 3.0, January 25, 2024.

Study design

This is a nonrandomized, single-arm, single-institution, Phase 1 study of adult patients with LAPC. MCC is responsible for the coordination and trial management, and quality assurance including reporting, monitoring, and database management. To be eligible for this study, patients must first have registered and been consented to the TCC, which is the MCC Institutional Biobanking protocol. The TCC provides systematic consent, biospecimen collection, and patient-survival follow-up. Specimens from both TCC and this study will be used in future correlative studies to analyze the study’s exploratory endpoints. Consent and enrollment into this study begins after completion of SoC CHT and RT. SoC CHT must have consisted of at least six 14-day cycles over 12 weeks (± 7 days) of FOLFIRINOX, and standard imaging after chemotherapy. The latter may have occurred on the last day of chemotherapy but must have occurred before RT. RT must have consisted of Ablative Stereotactic Magnetic Resonance Image- Guided Adaptive RT (A-SMART) dosed at 10 Gy per fraction for a total of 50 Gy (isotoxic approach), delivered daily (Monday–Friday, with breaks for weekends and holidays), have occurred 7 to 21 days after the last day of SoC CHT, along with imaging after RT. The latter may have occurred within 4 weeks (± 7 days) after RT. IRE will occur on day 0, along with blood banking and tumor- tissue banking. IO will occur on day 5 (± 7 days), during which participants will be administered pembrolizumab (IO) as a single 200 mg dose via a 30 min intravenous infusion. Blood banking will again occur on the day of IO (before administration) and within 7 days following pembrolizumab administration. A biopsy after IO will also be an option, on the day of the latter blood banking. Participants will have their After Treatment Visit on day 36, with End-of-Study Visit on day 95. The study schema is shown in Figure 1.

Figure 1: Clinical trial schema. Note: CHT: Chemotherapy; IO: Immunotherapy; IRE: Irreversible Electroporation; RT: Radiation Therapy; TCC: Total Cancer Care.

This Phase 1 study is designed to test the treatment safety and preliminary efficacy of combining sequential therapy of CHT, RT, IRE, and IO. This is an open-label, single-arm study with no randomization. Three patients will first receive the combined sequential therapy of CHT, RT, IRE, and IO. If none of the first 3 patients experience any Dose-Limiting Toxicities (DLT, defined as grade 3 or higher toxicities) definitively related to IRE and/or IO, we will conduct a Phase 2 of the study at a later date. If there is one DLT within the first 3 patients definitively related to IRE and/or IO, we will enroll an additional 3 patients. If no patients experience any DLT within the additional 3 patients definitively related to IRE and/or IO, we will conduct a Phase 2 of the study at a later date. Otherwise, we will not proceed to the Phase 2 study. If there is any fatal event (grade 5), the study will be closed with no further enrollment. Patients will undergo Standard-of- Care (SoC) active surveillance every 3 months (Q3Mo) after IO pembrolizumab for 24 months. SoC assessments include but are not limited to physical exam, vital signs, medical history, Eastern Cooperative Oncology Group status, hematology, chemistry, thyroid tests, blood collection, tumor markers, and imaging. All the patients will also be followed for vital status for up to at least 24 months after the IO dose for this Phase 1 study.

Eligibility criteria

All patients must provide informed consent before enrollment into the trial. Patients with a histologically confirmed diagnosis of localized LAPC and completion of Standard-of-Care Chemotherapy (SoC CHT) and RT can be included in this study. Patients can receive SoC CHT at an outside cancer center, but RT must be performed at the study institution. The main exclusion criteria are metastatic disease; gastrointestinal arteriovenous malformations; local gastrointestinal organ (eg, stomach, duodenum) invasion by tumor; and contraindications to ICI therapy. All eligibility criteria are shown in Table 1.

Table 1: Inclusion and exclusion criteria.

Objectives

The primary objective of this study is to determine the safety and tolerability of combining sequential therapy of IRE and IO for patients with locally advanced unresectable pancreas cancer following first-line therapy (CHT and RT). Secondary objectives are related to disease control efficacy and include evaluation of Progression-Free Survival (PFS), OS, and objective response rate.

Exploratory objectives are concerned with the evaluation of the presence and degree of conversion from an immunosuppressive to an immunopermissive tumoral environment using comparative immunology biomarkers in blood and tumor tissue at time points between various interventions (e.g., single-cell RNA sequencing, neutrophil-lymphocyte ratio, T-Cell Receptor (TCR) repertoire, CD4⁺ T regulatory cells, and myeloid-derived suppressor cells). We will also evaluate the immunologic changes occurring in patients treated with combining sequential therapy of CHT, A-SMART, IRE, and IO and evaluate the effect on their pancreatic tumor markers.

Primary endpoint: Rate of high-grade (grade 3-5) adverse events based on the NCI Common Terminology Criteria for Adverse Events, version 5 related to treatment, measured from IRE through 90 days following IO.

Secondary endpoints: 1) PFS is defined as the time from the date of diagnosis to the first documented tumor progression or death by any cause, whichever occurs first, 2) OS is defined as the time from the date of diagnosis to the time of by any cause, 3) The objective response rate is defined as the proportion of patients with either a partial or complete response according to iRECIST, version 1.1 guidelines, measured from date of diagnosis [29].

Exploratory endpoints: 1) Immunologic markers on serum and blood (4-1BB, OX40, LAG3, ICOS, GITR, CTLA4, TIM-3 and PD-1), including the neutrophil-lymphocyte ratio, myeloid- derived suppressor cells (CD11b+Gr-1+), and TCR repertoire of CD8⁺ T cells (CD3⁺, CD8⁺), CD4⁺ T effector cells (T eff; CD3⁺, CD4⁺, FOXP3−) and CD4⁺ T regulatory cells (Tregs; CD3⁺, CD4⁺, FOXP3, +CD127−/lo), will be assessed according to the schema (Figure 1). We will discern the profile of tumor and TME cells by comparing immunologic cells from biopsies performed on the initial diagnostic pretreatment tumor specimen (TCC collection), intraoperative biopsy during IRE following the induction CHT and A-SMART (T2) (Figure 1), and finally, after IRE and IO therapy (T3) (Figure 1), 2) Tumor markers will be assessed and explored at the study time points (T1-T3) (Figure 1), as well as during follow-up. The tumor markers will include standard clinical markers such as Carbohydrate Antigen (CA)19-9, carcinoembryonic antigen, and CA-125 and novel markers in development such as circulating- tumor DNA (ctDNA) (T1-T3) (Figure 1), immunophenotyping (T1- T3) (Figure 1), cytokines, and TCR clonality, as well as radiomics.

First-strike therapy

Chemotherapy: All patients must have undergone SoC CHT of FOLFIRINOX for at least 6 cycles (12 weeks). It will be acceptable for patients to have received SoC CHT at an outside institution.

Radiation therapy: RT will be performed with an A-SMART approach on the Magnetic Resonance Imaging (MRI)-guided linear accelerator (MRL), ViewRay MRIdian (ViewRay) [30]. Treatment details at our institution have been previously reported [31-33]. A-SMART simulation will be performed without fiducial marker placement because of the direct tumor visualization provided by the ViewRay MRIdian system, obviating the need for a surrogate marker. Simulation will be performed with the patient laying supine with arms at their side for patient comfort without immobilization and with Deep Inspiration Breath Hold (DIBH) for 25 sec to obtain a 3-dimensional magnetic resonance image and a representative sagittal slice where the primary tumor is identified. MRIdian uses the MRI balanced steady-state free precession sequence (TrueFISP). The patient will be subsequently marked at the laser sites and taken to the Computed Tomography (CT) simulator. The patient is then placed in an identical supine position and undergoes a DIBH with and without intravenous and oral contrast. Target and Organ-at-Risk (OAR) contours are performed on the radiotherapy TrueFISP scan. The CT scan will then be deformably registered to the TrueFISP scan for predictive dose calculation. The MRIdian system uses a step-and-shoot intensity-modulated (RT) treatment delivery technique. Intensity-modulated RT plans will be generated with Monte Carlo dose calculation and magnetic field corrections.

Gross target volume and tumor-vessel interface are defined as gross tumor within pancreas as seen on diagnostic imaging and simulation CT or MR scans. This volume will be expanded by 3 mm to create the nominal Planning Target Volume (PTV). The PTV is then isotropically expanded by 3 cm to create an OAR evaluation structure, within which the OAR will be recontoured daily. OARs that require contours include the stomach, duodenum, small bowel, large bowel, kidneys, liver, and spinal cord. OARs that may trigger adaptation, including the duodenum, stomach, and bowel, are combined into a single structure and expanded by 5 mm to create a planning organ-at-risk volume. This avoidance structure is then subtracted from the nominal PTV to generate a PTVopti structure that will be modified by the daily adaptation process. The densWater, densAir, and densOther structures must also be added before plan exportation to account for daily density changes. PTV prescriptions will be 50 Gy delivered in 5 fractions in an isotoxic approach.

Before treatment delivery, the base plan will be used to determine the predicted dose distribution on the anatomy of the day. The new target and OAR metrics achieved by the initial plan on the daily anatomy are then evaluated to see if violations occur (Table 2). Online adaptation will be triggered if there was insufficient PTV coverage or if the critical OAR dose exceeded the predetermined allowed limits. Real-time tracking on a sagittal scan every 250 ms is performed with automatic gating (beam pause if target moves >5% outside of prespecified region). DIBH is used during treatment to optimize duty-cycle efficiency.

Second-strike therapy

Table 2: Dose Constraints for 5 Fraction A-SMART for LAPC.

Irreversible electroporation: The study intervention of IRE is a relatively new technology that is a potentially ideal solution for ablating unresectable LAPC because IRE does not induce thermal tissue damage, thus avoiding injury to blood vessels and pancreatic and biliary ducts [21,22,34]. In this clinical study of IRE ablation using NanoKnife (AngioDynamics), we will perform the procedure according to the established standards and manufacturer’s instructions. Cardiac monitoring/synchronization will be used in accordance with the NanoKnife instructions. The technical specifications for use are described in Table 3. The maximum electroporation voltage, IRE pulsing scheme, and number of electrodes will depend upon the patient’s specific tumor characteristics but will always be done according to the manufacturer’s instructions.

Table 3: Irreversible electroporation treatment parameters.

Immune checkpoint inhibitor therapy: Patients will be administered pembrolizumab as a single 200 mg dose via a 30 min intravenous infusion, administered within approximately 1 week after IRE.

Radiological and pathological treatment evaluation: In accordance with NCCN guidelines, imaging will include CT of the chest and abdomen/pelvis pancreas. MRI and/or endoscopic ultrasound will be included as needed. However, it is expected that all second- strike imaging (i.e., after IRE and IO imaging), will be performed via CT. Imaging after IRE will occur 1 week (± 3 days) after IRE, on the same day as IO treatment but before the IO treatment on that day. Imaging after IO will occur 4 weeks (± 14 days) after the single IO dose (or 3 months (± 14 days after the last previously performed imaging)). Imaging after IO may occur within 1 week before the first follow-up visit, but if imaging occurs on the same day as the end-of-study visit, then it needs to be completed before the appointment with enough time for a diagnostic radiology read. All second-strike imaging (i.e., imaging after IRE and IO) should be performed via CT.

Core needle biopsies will be performed at the time of IRE and at 4 weeks after IO. The biopsy sample from the time of IRE will be used to assess the pathological response to first-strike therapy; the sample from after IO will be used to assess the response to second- strike therapy. The treatment response will be assessed according to the tumor-regression grading system of the College of American Pathologists.

Concomitant therapy: Using concomitantly prescribed drugs is allowed during this study. Participants may also take over-the- counter medication as needed. However, steroid medications or any herbal supplements containing steroids are prohibited.

Follow-up and adverse-event assessment: Adverse Events (AE) and Serious Adverse Events (SAE) assessment will occur during all clinical visits after time of enrollment. Collection will continue through 90 days (AE) and 30 days (SAE) following the end-of-study treatment (i.e., the single pembrolizumab IO dose). Survival will be assessed up to 24 months after the single pembrolizumab IO dose.

Follow-ups after IO imaging will occur every 3 months. Grading of AEs will be documented based on the Common Terminology Criteria for Adverse Events, version 5.0. SAEs will be those that result in death; a life-threatening AE; inpatient hospitalization or prolongation of existing hospitalization; a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions; or a congenital anomaly or birth defect. Any medical condition that is present when the participant is screened will be considered baseline and not reported as an AE. Participants removed from study for unacceptable AEs will be followed until resolution or stabilization of the AE.

Statistical considerations: Data will be summarized overall using descriptive statistics. For example, continuous data will be summarized with the number of patients (n), mean, median, minimum, maximum, standard deviation, coefficient of variation, and geometric mean (where applicable). Categorical data will be summarized using frequency counts and percentages. The occurrence of DLT will be summarized by frequencies and percentages. Response rates and 95% confidence intervals will be calculated using Wilson’s method for binomial probability distributions. OS and PFS will be estimated using the Kaplan– Meier method. If estimable, median OS and PFS with 95% confidence intervals will also be determined. Objective response will be summarized descriptively using frequencies and percentages.

Results

As the Phase 1 trial is currently ongoing, specific results regarding the safety and efficacy of the sequential combination therapy involving CHT, RT, IRE, and pembrolizumab in patients with LAPC have not yet been fully analyzed or reported. However, the trial is designed to assess several key endpoints, including treatment tolerability, preliminary efficacy, and changes in the TME.

The study aims to collect data on adverse events and responses to treatment through various assessments, including imaging studies, biopsy evaluations, and biomarker analyses. Initial observations suggest that the combination therapy may have the potential to enhance immune activation and induce significant alterations within the TME, although comprehensive results will be available upon completion of the trial.

Discussion

This novel treatment approach is based on an evolutionary dynamics model and is the first to adapt insights from Anthropocene extinction events into treating PDAC. This trial uses 2 local therapies (RT and IRE) to prime the TME for sequential IO. If successful, this trial would have implications beyond LAPC. We would be demonstrating the possibility of improving clinical outcomes by integrating evolutionary dynamic models into trial design.

Anthropocene extinction events demonstrate that populations often follow one of 2 patterns after experiencing an initial insult. These populations enter an extinction vortex, and then they are either diminished to a point where they cannot recover and face eventual extinction, or they rebound after having been selected for resistance against the initial insult. Intentional Anthropocene extinctions have taught us that a window exists after the initial insult (first strike) that allows for another insult (second strike) to push these populations to complete eradication after entering the extinction vortex [35,36]. However, for these second strikes to be effective, they often cannot rely upon the same strategies for continued demographic perturbation due to selection pressure [36]. Instead, an alternative strategy must be applied that can cause an entirely different form of evolutionary pressure. The strategy that would make a second strike effective often would not be effective as an initial strike because it relies upon the unique ecological system generated by the first strike. The temporal ecological disruption caused by the first strike to generate the extinct vortex enables the second strike to push the remaining populace to inevitable extinction, thus highlighting the importance of timing in a successful second strike. These lessons can be applied to the treatment of cancer and the dynamics of adjuvant therapy.

Initial cancer therapies typically result in significant reduction of the global tumor population [37]. Nearly all adjuvant therapy protocols focus on continued demographic perturbations. That is, they directly attack individual cancer cells to alter the proliferation and death rates of the population. Many times, this strategy will eventually result in a successful extinction vortex, thus eradicating the remaining cancer cells [38]. However, if resistance develops and manages to successfully produce a growing cohort before fading out, a surviving population could permit evolutionary rescue, such that the tumor recovers and proliferates, eventually forming clinical metastases [36-38]. The period of time when the tumor is in the extinction vortex represents an opportunity to add new treatments for accelerating the extinction process and for reducing the risk of evolutionary rescue. However, in cancer, these tumor populations often have subpopulations with varying resistance to adjuvant therapy. In addition, these subpopulations rely on direct cell kill and, consequently, they present risks selecting for resistance phenotypes [39]. If adjuvant therapy can produce a permanent ecological disruption, then this entirely different form of selection pressure is applied that can affect the entire remaining tumor population [36-38]. By using a second strike in LAPC that focuses on permanent ecological disruption to the entire TME, a more sustained response may be achievable. Specifically, the activation of coexisting immune cells by IO has the potential to induce these long-lasting changes in the TME caused by eradication of small or subclinical cancer cell populations. However, pancreatic adenocarcinoma is known to be a cold tumor, meaning that very few antitumor immune cells are able to penetrate into or around the tumor, thus minimizing the efficacy of immune checkpoint inhibitors [40]. Fortunately, both ablative RT and IRE have been shown to potentiate immune response after therapy. These therapies may be able to convert this tumor into a more immune-permissive state during the extinction vortex window and allow for more permanent ecological changes of the TME via IO.

Preclinical data suggest that radiation enhances the antigenicity of tumors [41-44]. An orthotopically implanted PDAC-tumor murine model demonstrated that radiation enhances T-cell responses to immunogenic tumor baseline responsiveness to single-agent Programmed Death-1 receptor (PD-1) blockade [45]. In addition to enhancing T-cell responses, radiation-induced immunogenic cell death also triggers negative feedback in the form of immunosuppressive myeloid cells; these cells infiltrate the irradiated tumor and surrounding tissues to support wound healing and tissue homeostasis. This immune reaction also affects hematopoiesis in the bone marrow, leading to systemic release of immune-suppressive myeloid cells into circulation [46]. Specifically, this was shown in a murine model of ablative RT in combination with IO [47]. Therefore, preclinical data suggest that ablative RT may offer a unique immunomodulatory priming effect before IRE.

Additionally, IRE has demonstrated potential to induce a more immunopermissive TME in PDAC for IO in both preclinical and clinical studies. IRE can induce transient softening of tumor stroma, increase microvascular density, and increase permeability as recently shown in an orthotopic murine PDAC model [48]. These effects reversed resistance to anti–PD-1 therapy, inducing CD8⁺ T-cell infiltration and immunogenic cell death of cancer cells more effectively than the combination of irradiation and anti- PD-1 therapy, with significantly prolonged survival. Additionally, an immunocompetent mouse model demonstrated that combining IRE with the intratumoral Toll-like receptor 7 agonist and systemic anti–PD-1 checkpoint blockade resulted in both regression of primary tumor and elimination of untreated concomitant distant tumors (abscopal effect) [49]. These results suggest that the systemic antitumor immune response triggered by IRE can be enhanced by stimulating the innate immune system as well as the adaptive immune system. Similarly, IRE of LAPC transiently alleviates immune suppression and creates a window for antitumor T-cell activation. Moreover, after IRE, the tumor-specific systemic T-cell response to the PDAC-associated antigen, Wilms tumor 1, was related to longer OS [50]. Clinical evidence has also demonstrated how IRE attenuated the effect of CD4⁺ regulatory T cells (Tregs) in 11 patients with LAPC between postoperative days 3 and 5 [51].

We report preclinical and clinical observations of IRE modulation of the immune environment to enhance the effectiveness of IO and the effectiveness of pembrolizumab as IO with engagement of the immune system. Further, these observations suggested the logical next step of investigating IRE combined with pembrolizumab in LAPC. A Phase 1b trial investigated the use of concurrent IO and IRE in LAPC, which demonstrated both feasibility and safety of combining these therapies [52]. In the context of this proposal, none of the previous or ongoing clinical trials aim to assess the role of sequential IRE with IO as part of a multistrike treatment approach following first-line CHT and RT. We anticipate that sequential use of CHT, RT, and IRE will alter the cold PDAC TME to hot, thereby making it more responsive to checkpoint inhibitor therapy with pembrolizumab.

Furthermore, we also aim to improve understanding of LAPC radiobiology. For this effort, we will use the diagnostic biopsy tissue, tissue taken during IRE, and tissue taken after IO to study the impact of the different therapies to better understand their influence upon TME, genomics, pathways activated, and the contribution to circulating-tumor DNA (ctDNA). Radiomic data will be collected from any imaging, including of diagnostic examination, restaging after therapy, and follow-up. These data will be analyzed in conjunction with blood, plasma, and tumor genomic data to identify potential radiomic and genomic biomarkers. These biomarkers have considerable potential to guide future studies to improve personalized RT for LAPC, such as improving patient selection and predicting patients at high-risk for treatment failure who may benefit from further adjuvant therapies.

Overall, this trial takes full advantage of current understanding within the fields of cancer biology, evolutionary oncology, radiation oncology, gastrointestinal oncology, and immuno-oncology, to push beyond the current treatment paradigm for LAPC. This trial represents an important step toward incorporating evolutionary oncology concepts by using sequential combinational therapies to purposefully induce an extinction vortex and subsequent extinction of cancer cells. If successful, we will build from this trial and open a randomized Phase 2 to determine the efficacy of the IO within this treatment paradigm. In addition, the insights gathered may also enable the identification of novel biomarkers that may refine current personalized strategies for LAPC patients.

Conclusion

While definitive results from this ongoing Phase 1 trial are pending, the design and objectives hold potential for advancing treatment strategies for LAPC. Should the trial demonstrate favorable safety and efficacy profiles, it will lead to the development of a Phase 2 randomized trial to further evaluate this innovative approach. Additionally, the insights gained may contribute to identifying novel biomarkers for personalized therapies, ultimately aiming to improve outcomes for patients facing this aggressive malignancy. The findings of this study could significantly enhance our understanding of LAPC treatment and lead to future therapeutic advancements.

Funding

Partial funding from AngioDynamics, Inc. and the Moffitt Foundation.

Competing Interests

No author has any conflicts of interest pertaining to this work.

References

1. Siegel RL, Miller KD, Fuchs HE, Jemal A. Cancer Statistics, 2021. CA Cancer J Clin. 2021;71(1):7-33.

   [Crossref] [Google Scholar] [PubMed]

2. Rahib L, Smith BD, Aizenberg R, Rosenzweig AB, Fleshman JM, Matrisian LM. Projecting cancer incidence and deaths to 2030: The unexpected burden of thyroid, liver, and pancreas cancers in the United States. Cancer Res. 2014;74(11):2913-2921.

   [Crossref] [Google Scholar] [PubMed]

3. Tempero MA, Malafa MP, Al-Hawary M, Behrman SW, Benson AB, Cardin DB, et al. Pancreatic adenocarcinoma, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw. 2021;19(4):439-457.

   [Crossref] [Google Scholar] [PubMed]

4. Blakaj A, Stein SM, Khan SA, Johung KL. Review and current state of radiation therapy for locally advanced pancreatic adenocarcinoma. J Gastrointest Oncol. 2018;9(6):1027-1036.

   [Crossref] [Google Scholar] [PubMed]

5. Park W, Chawla A, O'Reilly EM. Pancreatic cancer: A review. JAMA. 2021;326(9):851-862.

   [Crossref] [Google Scholar] [PubMed]

6. Hodi FS, O'Day SJ, McDermott DF, Weber RW, Sosman JA, Haanen JB, et al. Improved survival with ipilimumab in patients with metastatic melanoma. N Engl J Med. 2010;363(8):711-723.

   [Crossref] [Google Scholar] [PubMed]

7. Borghaei H, Paz-Ares L, Horn L, Spigel DR, Steins M, Ready NE, et al. Nivolumab versus docetaxel in advanced nonsquamous non-small-cell lung cancer. N Engl J Med. 2015;373(17):1627-1639.

   [Crossref] [Google Scholar] [PubMed]

8. Balachandran VP, Beatty GL, Dougan SK. Broadening the impact of immunotherapy to pancreatic cancer: Challenges and opportunities. Gastroenterology. 2019;156(7):2056-2072.

   [Crossref] [Google Scholar] [PubMed]

9. Royal RE, Levy C, Turner K, Mathur A, Hughes M, Kammula US, et al. Phase 2 trial of single agent Ipilimumab (anti-CTLA-4) for locally advanced or metastatic pancreatic adenocarcinoma. J Immunother. 2010;33(8):828-833.

   [Crossref] [Google Scholar] [PubMed]

10. Feig C, Gopinathan A, Neesse A, Chan DS, Cook N, Tuveson DA. The pancreas cancer microenvironment. Clin Cancer Res. 2012;18(16):4266-4276.

    [Crossref] [Google Scholar] [PubMed]

11. Provenzano PP, Cuevas C, Chang AE, Goel VK, Von Hoff DD, Hingorani SR. Enzymatic targeting of the stroma ablates physical barriers to treatment of pancreatic ductal adenocarcinoma. Cancer Cell. 2012;21(3):418-429.

    [Crossref] [Google Scholar] [PubMed]

12. Pergamo M, Miller G. Myeloid-derived suppressor cells and their role in pancreatic cancer. Cancer Gene Ther. 2017;24(3):100-105.

    [Crossref] [Google Scholar] [PubMed]

13. Clark CE, Hingorani SR, Mick R, Combs C, Tuveson DA, Vonderheide RH. Dynamics of the immune reaction to pancreatic cancer from inception to invasion. Cancer Res. 2007;67(19):9518-9527.

    [Crossref] [Google Scholar] [PubMed]

14. Sonbol MB, Ahn DH, Goldstein D, Okusaka T, Tabernero J, Macarulla T, et al. CanStem111P trial: A Phase III study of napabucasin plus nab-paclitaxel with gemcitabine. Future Oncol. 2019;15(12):1295-1302.

    [Crossref] [Google Scholar] [PubMed]

15. Quail DF, Joyce JA. Microenvironmental regulation of tumor progression and metastasis. Nat Med. 2013;19(11):1423-1437.

    [Crossref] [Google Scholar] [PubMed]

16. Beatty GL, O'Hara M. Chimeric antigen receptor-modified T cells for the treatment of solid tumors: Defining the challenges and next steps. Pharmacol Ther. 2016;166:30-39.

    [Crossref] [Google Scholar] [PubMed]

17. Kwon W, Thomas A, Kluger MD. Irreversible electroporation of locally advanced pancreatic cancer. Semin Oncol. 2021;48(1):84-94.

    [Crossref] [Google Scholar] [PubMed]

18. Dimcevski G, Kotopoulis S, Bjanes T, Hoem D, Schjott J, Gjertsen BT, et al. A human clinical trial using ultrasound and microbubbles to enhance gemcitabine treatment of inoperable pancreatic cancer. J Control Release. 2016;243:172-181.

    [Crossref] [Google Scholar] [PubMed]

19. Keisari Y. Tumor abolition and antitumor immunostimulation by physico-chemical tumor ablation. Front Biosci (Landmark Ed) 2017, 22(2):310-347.

    [Crossref] [Google Scholar] [PubMed]

20. Postow MA, Callahan MK, Barker CA, Yamada Y, Yuan J, Kitano S, et al. Immunologic correlates of the abscopal effect in a patient with melanoma. N Engl J Med. 2012;366(10):925-931.

    [Crossref] [Google Scholar] [PubMed]

21. Ansari D, Kristoffersson S, Andersson R, Bergenfeldt M. The role of Irreversible Electroporation (IRE) for locally advanced pancreatic cancer: A systematic review of safety and efficacy. Scand J Gastroenterol 2017;52(11):1165-1171.

    [Crossref] [Google Scholar] [PubMed]

22. Martin RCG. Irreversible electroporation of stage 3 locally advanced pancreatic cancer: Optimal technique and outcomes. J Vis Surg. 2015;1:4.

    [Crossref] [Google Scholar] [PubMed]

23. Chan G, Pua U. Irreversible electroporation of the pancreas. Semin Intervent Radiol. 2019;36(3):213-220.

    [Crossref] [Google Scholar] [PubMed]

24. Holland MM, Bhutiani N, Kruse EJ, Weiss MJ, Christein JD, White RR, et al. A prospective, multi-institution assessment of irreversible electroporation for treatment of locally advanced pancreatic adenocarcinoma: Initial outcomes from the AHPBA pancreatic registry. HPB (Oxford). 2019;21(8):1024-1031.

    [Crossref] [Google Scholar] [PubMed]

25. Martin RC, Kwon D, Chalikonda S, Sellers M, Kotz E, Scoggins C, et al. Treatment of 200 locally advanced (stage III) pancreatic adenocarcinoma patients with irreversible electroporation: Safety and efficacy. Ann Surg. 2015;262(3):486-494.

    [Crossref] [Google Scholar] [PubMed]

26. Moris D, Machairas N, Tsilimigras DI, Prodromidou A, Ejaz A, Weiss M, et al. Systematic review of surgical and percutaneous irreversible electroporation in the treatment of locally advanced pancreatic cancer. Ann Surg Oncol. 2019;26(6):1657-1668.

    [Crossref] [Google Scholar] [PubMed]

27. Narayanan G, Bilimoria MM, Hosein PJ, Su Z, Mortimer KM, Martin RCG, et al. Multicenter randomized controlled trial and registry study to assess the safety and efficacy of the NanoKnife® system for the ablation of stage 3 pancreatic adenocarcinoma: Overview of study protocols. BMC Cancer. 2021;21(1):785.

    [Crossref] [Google Scholar] [PubMed]

28. Narayanan G, Hosein PJ, Beulaygue IC, Froud T, Scheffer HJ, Venkat SR, et al. Percutaneous image-guided irreversible electroporation for the treatment of unresectable, locally advanced pancreatic adenocarcinoma. J Vasc Interv Radiol. 2017;28(3):342-348.

    [Crossref] [Google Scholar] [PubMed]

29. Seymour L, Bogaerts J, Perrone A, Ford R, Schwartz LH, Mandrekar S, et al. iRECIST: Guidelines for response criteria for use in trials testing immunotherapeutics. Lancet Oncol. 2017;18(3):e143-e152.

    [Crossref] [Google Scholar] [PubMed]

30. Bryant JM, Weygand J, Keit E, Cruz-Chamorro R, Sandoval ML, Oraiqat IM, et al. Stereotactic magnetic resonance-guided adaptive and non-adaptive radiotherapy on combination MR-linear accelerators: Current practice and future directions. Cancers (Basel). 2023;15(7):2081.

    [Crossref] [Google Scholar] [PubMed]

31. Bryant J, Palm RF, Herrera R, Rubens M, Hoffe SE, Kim DW, et al. Multi-institutional outcomes of patients Aged 75 years and older with pancreatic ductal adenocarcinoma treated with 5-fraction Ablative Stereotactic Magnetic Resonance Image-Guided Adaptive Radiation Therapy (A-SMART). Cancer Control. 2023;30:10732748221150228.

    [Crossref] [Google Scholar] [PubMed]

32. Bryant JM, Palm RF, Liveringhouse C, Boyer E, Hodul P, Malafa M, et al. Surgical and pathologic outcomes of Pancreatic Adenocarcinoma (PA) after preoperative ablative stereotactic magnetic resonance image guided Adaptive Radiation Therapy (A-SMART). Adv Radiat Oncol. 2022;7(6):101045.

    [Crossref] [Google Scholar] [PubMed]

33. Sim AJ, Hoffe SE, Latifi K, Palm RF, Feygelman V, Leuthold S, et al. A practical workflow for magnetic resonance-guided stereotactic body radiation therapy to the pancreas. Pract Radiat Oncol. 2023;13(1):e45-e53.

    [Crossref] [Google Scholar] [PubMed]

34. Lafranceschina S, Brunetti O, Delvecchio A, Conticchio M, Ammendola M, Currò G, et al. Systematic review of irreversible electroporation role in management of locally advanced pancreatic cancer. Cancers (Basel). 2019;11(11).

    [Crossref] [Google Scholar] [PubMed]

35. Bozic I, Wu CJ. Delineating the evolutionary dynamics of cancer from theory to reality. Nat Cancer. 2020;1(6):580-588.

    [Crossref] [Google Scholar] [PubMed]

36. Gatenby RA, Brown JS. Integrating evolutionary dynamics into cancer therapy. Nat Rev Clin Oncol. 2020;17(11):675-686.

    [Crossref] [Google Scholar] [PubMed]

37. Persi E, Wolf YI, Horn D, Ruppin E, Demichelis F, Gatenby RA, et al. Mutation-selection balance and compensatory mechanisms in tumour evolution. Nat Rev Genet. 2021;22(4):251-262.

    [Crossref] [Google Scholar] [PubMed]

38. Artzy-Randrup Y, Epstein T, Brown JS, Costa RLB, Czerniecki BJ, Gatenby RA. Novel evolutionary dynamics of small populations in breast cancer adjuvant and neoadjuvant therapy. NPJ Breast Cancer. 2021;7(1):26.

    [Crossref] [Google Scholar] [PubMed]

39. Aslakson CJ, Miller FR. Selective events in the metastatic process defined by analysis of the sequential dissemination of subpopulations of a mouse mammary tumor. Cancer Res. 1992;52(6):1399-1405.

    [Google Scholar] [PubMed]

40. Liu YT, Sun ZJ. Turning cold tumors into hot tumors by improving T-cell infiltration. Theranostics. 2021;11(11):5365-5386.

    [Crossref] [Google Scholar] [PubMed]

41. Lugade AA, Moran JP, Gerber SA, Rose RC, Frelinger JG, Lord EM. Local radiation therapy of B16 melanoma tumors increases the generation of tumor antigen-specific effector cells that traffic to the tumor. J Immunol. 2005;174(12):7516-7523.

    [Crossref] [Google Scholar] [PubMed]

42. Apetoh L, Ghiringhelli F, Tesniere A, Obeid M, Ortiz C, Criollo A, et al. Toll-like receptor 4-dependent contribution of the immune system to anticancer chemotherapy and radiotherapy. Nat Med. 2007;13(9):1050-1059.

    [Crossref] [Google Scholar] [PubMed]

43. Matsumura S, Wang B, Kawashima N, Braunstein S, Badura M, Cameron TO, et al. Radiation-induced CXCL16 release by breast cancer cells attracts effector T cells. J Immunol. 2008;181(5):3099-3107.

    [Crossref] [Google Scholar] [PubMed]

44. Dewan MZ, Galloway AE, Kawashima N, Dewyngaert JK, Babb JS, Formenti SC, et al. Fractionated but not single-dose radiotherapy induces an immune-mediated abscopal effect when combined with anti-CTLA-4 antibody. Clin Cancer Res. 2009;15(17):5379-5388.

    [Crossref] [Google Scholar] [PubMed]

45. Fujiwara K, Saung MT, Jing H, Herbst B, Zarecki M, Muth S, et al. Interrogating the immune-modulating roles of radiation therapy for a rational combination with immune-checkpoint inhibitors in treating pancreatic cancer. J Immunother Cancer. 2020;8(2):e000351.

    [Crossref] [Google Scholar] [PubMed]

46. Krall JA, Reinhardt F, Mercury OA, Pattabiraman DR, Brooks MW, Dougan M, et al. The systemic response to surgery triggers the outgrowth of distant immune-controlled tumors in mouse models of dormancy. Sci Transl Med 2018;10(436).

    [Crossref] [Google Scholar] [PubMed]

47. Stump CT, Roehle K, Manjarrez Orduno N, Dougan SK. Radiation combines with immune checkpoint blockade to enhance T cell priming in a murine model of poorly immunogenic pancreatic cancer. Open Biol. 2021;11(11):210245.

    [Crossref] [Google Scholar] [PubMed]

48. Zhao J, Wen X, Tian L, Li T, Xu C, Wen X, et al. Irreversible electroporation reverses resistance to immune checkpoint blockade in pancreatic cancer. Nat Commun. 2019;10(1):899.

    [Crossref] [Google Scholar] [PubMed]

49. Narayanan JSS, Ray P, Hayashi T, Whisenant TC, Vicente D, Carson DA, et al. Irreversible electroporation combined with checkpoint blockade and TLR7 stimulation induces antitumor immunity in a murine pancreatic cancer model. Cancer Immunol Res. 2019;7(10):1714-1726.

    [Crossref] [Google Scholar] [PubMed]

50. Scheffer HJ, Stam AGM, Geboers B, Vroomen L, Ruarus A, de Bruijn B, et al. Irreversible electroporation of locally advanced pancreatic cancer transiently alleviates immune suppression and creates a window for antitumor T cell activation. Oncoimmunology. 2019;8(11):1652532.

    [Crossref] [Google Scholar] [PubMed]

51. Pandit H, Hong YK, Li Y, Rostas J, Pulliam Z, Li SP, et al. Evaluating the regulatory immunomodulation Effect of Irreversible Electroporation (IRE) in pancreatic adenocarcinoma. Ann Surg Oncol. 2019;26(3):800-806.

    [Crossref] [Google Scholar] [PubMed]

52. O'Neill C, Hayat T, Hamm J, Healey M, Zheng Q, Li Y, et al. A phase 1b trial of concurrent immunotherapy and irreversible electroporation in the treatment of locally advanced pancreatic adenocarcinoma. Surgery. 2020;168(4):610-616.

    [Crossref] [Google Scholar] [PubMed]