Role of Immunotherapy in Gastroesophageal Cancers-Advances, Challenges and Future Strategies

BACKGROUND

Gastroesophageal cancers (GECs) carry considerable morbidity and mortality, and demonstrate geographical histological variances in addition to molecular heterogeneity. Consequently, the immunogenicity of the different subtypes, which can predict the likelihood of immunotherapy response, can vary. Immune checkpoint inhibitor (ICI) therapy has transformed the treatment of many cancer types over the past decade but has been slower to gain a foothold in the treatment paradigm of GECs.

METHODS

This article reviews the existing evidence and use approvals for immunotherapies and immune-based treatments in GECs, in the neoadjuvant, adjuvant and metastatic disease settings. The challenges of and limitations to ICI application in current clinical practice are examined. Ongoing clinical trials and future directions of research are also considered.

CONCLUSION

ICI therapy has become an established treatment option within GECs, both perioperatively and in advanced disease. However, nuances in terms of its use are not yet fully understood. Ongoing research proposes to broaden the application of immunotherapies in GECs with the potential to continue to improve outcomes.

Brave new world-new and emerging treatments for gastric cancer

Despite considerable international heterogeneity in the incidence and histological subtypes of gastric cancer (GC), in addition to more recent epidemiological trends, chemotherapy has long represented the main systemic therapeutic option in its treatment. For the roughly 20% of GC with human epidermal growth factor receptor 2 (HER2) overexpression, there is a more recently established role for the addition of HER2+ based therapy in the form of trastuzumab. However, while immune checkpoint inhibitors (ICIs) have revolutionised the treatment of other malignancies including melanoma and renal cell carcinoma over the past decade, they have only gained a foothold in GC in more recent years. This article reviews the existing evidence for ICIs in GC as a novel therapeutic option. It also looks to ongoing trials of immune checkpoint inhibition both in the perioperative and advanced setting, and in combination with other therapeutic targets including HER2+. Other investigational immune based therapies including chimeric antigen receptor T-cell (CAR-T) therapy and anti-T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (anti-TIGIT) therapy are considered, in addition to reviewing the building evidence for alternative therapeutic targets currently under investigation in GC, including fibroblast growth factor receptor 2b (FGFR2b) and claudin 18.2 amongst others. These novel and evolving targets represent a brave new world in therapeutic intervention in GC, with the potential to transform outcomes for patients internationally.

Phase I/II study of PexaVec in combination with immune checkpoint inhibition in refractory metastatic colorectal cancer

BACKGROUND

Oncolytic immunotherapy represents a unique therapeutic platform for the treatment of cancer. Here, we evaluated the safety and efficacy of the combination of pexastimogene devacirepvec (PexaVec) plus durvalumab (anti-programmed death ligand 1) with and without tremelimumab (anti-cytotoxic T-lymphocyte associated protein 4) in patients with standard chemotherapy refractory mismatch repair proficient (pMMR) metastatic colorectal cancer (mCRC) in a phase I/II trial.

METHODS

Adult patients with histologically confirmed advanced pMMR mCRC, who had progressed on at least two prior lines of systemic chemotherapy were studied in four cohorts. Patients received four doses of PexaVec IV at a dose of 3×10⁸ plaque forming units (pfu) (dose level 1) or 1×10⁹ pfu (dose level 2) every 2 weeks. Twelve days after the first PexaVec administration, patients received either 1500 mg of durvalumab every 28 days alone or an additional single dose of 300 mg tremelimumab on day 1. Responses were assessed every 8 weeks by CT or MRI. AEs were recorded. The primary endpoints were safety and feasibility. Secondary endpoints included progression-free survival (PFS) and overall survival. Paired tumor samples and peripheral blood were collected to perform immune monitoring.

RESULTS

Thirty-four patients with mCRC enrolled on to the study: 16 patients in the PexaVec/durvalumab cohorts and 18 patients in the PexaVec/durvalumab/tremelimumab cohorts. Overall, the combination of PexaVec plus immune checkpoint inhibitors did not result in any unexpected toxicities. Most common toxicities observed were fever and chills after PexaVec infusion. Two cases of grade 3 colitis, one case of a grade 2 myositis and one case of grade 3 hypotension resulted in discontinuation of immune checkpoint inhibitor and PexaVec treatment, respectively. The median PFS in the PexaVec/durvalumab/tremelimumab cohorts was 2.3 months (95% CI: 2.2 to 3.2 months) vs 2.1 months (95% CI: 1.7 to 2.8 months; p=0.57) in the PexaVec/durvalumab cohorts. Flow cytometry analysis of peripheral blood mononuclear cells revealed an increase in Ki67⁺CD8⁺ T cells on treatment.

CONCLUSION

PexaVec in combination with durvalumab and tremelimumab is safe and tolerable. No unexpected toxicities were observed. The combination of PexaVec/durvalumab/tremelimumab demonstrated potential clinical activity in patients with pMMR mCRC, but further studies are needed to identify the predictive biomarkers.

TRIAL REGISTRATION NUMBER

NCT03206073.

Prioritising Informed Health Choices Key Concepts for those impacted by cancer: a protocol

Background: Few areas of health have been as insidiously influenced by misinformation as cancer. Thus, interventions that can help people impacted by cancer reduce the extent to which they are victims of misinformation are necessary. The Informed Health Choices (IHC) initiative has developed Key Concepts that can be used in the development of interventions for evaluating the trustworthiness of claims about the effects of health treatments. We are developing an online education programme called Informed Health Choices-Cancer (IHC-C) based on the IHC Key Concepts. We will provide those impacted by cancer with the knowledge and skills necessary to think critically about the reliability of health information and claims and make informed choices. Methods: We will establish a steering group (SG) of 12 key stakeholders, including oncology specialists and academics. In addition, we will establish a patient and public involvement (PPI) panel of 20 people impacted by cancer. After training the members on the Key Concepts and the prioritisation process, we will conduct a two-round prioritisation process. In the first round, 12 SG members and four PPI panel members will prioritise Key Concepts for inclusion. In the second round, the remaining 16 PPI members will undertake the prioritisation based on the prioritised Key Concepts from the first round. Participants in both rounds will use a structured judgement form to rate the importance of the Key Concepts for inclusion in the online IHC-C programme. A consensus meeting will be held, where members will reach a consensus on the Key Concepts to be included and rank the order in which the prioritised Key Concepts will be addressed in the IHC-C programme. Conclusions: At the end of this process, we will identify which Key Concepts should be included and the order in which they should be addressed in the IHC-C programme.

Tremelimumab (day 1 only) and durvalumab in combination with transarterial chemoemobilization (TACE) in patients with hepatocellular carcinoma (HCC)

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Background: TACE induces a peripheral anti-tumor immune response, which may be amplified by immune checkpoint inhibitors (ICI). Combining TACE with dual ICI therapy has been shown to be safe and feasible. Recent data has suggested that Day-1 only anti-CTLA4 dosing, at a higher level of 300mg, could lead to a stronger immune response, and drive a greater expansion than lower dose regimens, whilst maintaining a tolerable safety profile. This novel schedule has not previously been combined with TACE. Methods: Patients with HCC (Childs Pugh A/B7, Barcelona clinic liver cancer stage B/C; ECOG 0/1; sorafenib-naive or experienced) were enrolled in a pilot study of tremelimumab at 2 dose levels (DL1: 75mg IV q4-weekly x 4 and DL2: 300mg IV D1 only) in combination with durvalumab (1500mg IV q-28d) and TACE (D36 +/- 96 hours) until progression of disease (per irRECIST) or off-study criteria. Peripheral immune monitoring was performed and tumor biopsies were obtained at time of TACE. Results: 13 patients enrolled on study; N = 3 at DL1 and N = 10 at DL2. M:F 10:3. Median age 70 (65-74). BCLC B/C 4/9. Extrahepatic disease 6/7. Aetiology: NASH (N = 3), alcohol-related disease (N = 1), HCV (N = 2), hemochromatosis (N = 1), unknown (N = 6). 1 pt discontinued due to G3 colitis. All patients evaluable for response with 2/10 pts on DL2 experiencing PR (at 8 weeks) and overall 7/13 SD and 1/13 PD as best response. Updated PFS and OS data to be presented. Conclusions: Tremelimumab (Day 1 only) and Durvalumab in combination with TACE is safe and feasible in patients with HCC. Follow-up is ongoing and full safety and efficacy data will be presented. Clinical trial information: 2019-002767-98.

Emerging RAS-directed therapies for cancer

RAS oncogenes are the most commonly mutated oncogenes in human cancer, and RAS-mutant cancers represent a major burden of human disease. Though these oncogenes were discovered decades ago, recent years have seen major advances in understanding of their structure and function, including the therapeutic and prognostic significance of diverse isoforms. Targeting of these mutations has proven difficult, despite some successes with inhibition of RAS effector signalling. More recently, direct RAS inhibition has been achieved in a trial setting. While this has yet to be translated to everyday clinical practice, this development carries much promise. This review summarizes the diverse approaches that have been taken to RAS inhibition and then focuses on the most recent developments in direct inhibition of KRAS(G12C).

Liver Immunology, Immunotherapy, and Liver Cancers: Time for a Rethink?

The complex immune system of the liver has a major role in tumor surveillance, but also partly explains why current immune therapies are poorly effective against liver cancers. Known primarily for its tolerogenic capacity, the hepatic immune repertoire also comprises diverse populations of armored immune cells with tumor surveillant roles. In healthy people, these work together to successfully identify malignant cells and prevent their proliferation, thus halting tumor formation. When frontline hepatic immune surveillance systems fail, compromised hepatic immunity, driven by obesity, infection, or other pathological factors, allows primary or secondary liver cancers to develop. Tumor growth promotes the normal tolerogenic immunological milieu of the liver, perhaps explaining why current immunotherapies fail to work. This review explores the complex local liver immune system with the hope of identifying potential therapeutic targets needed to best overcome immunological barriers in the liver to create an environment no longer hostile to immunotherapy for the treatment of liver cancer.

A Phase II Study of Pembrolizumab in Combination with Capecitabine and Oxaliplatin with Molecular Profiling in Patients with Advanced Biliary Tract Carcinoma

BACKGROUND

We conducted a phase II study of the combination of pembrolizumab with capecitabine and oxaliplatin (CAPOX) in patients with advanced biliary tract carcinoma (BTC) to assess response rate and clinical efficacy. Exploratory objectives included correlative studies of immune marker expression, tumor evolution, and immune infiltration in response to treatment.

PATIENTS AND METHODS

Adult patients with histologically confirmed BTC were enrolled and received oxaliplatin and pembrolizumab on day 1 of cycles 1-6. Capecitabine was administered orally twice daily as intermittent treatment, with the first dose on day 1 and the last dose on day 14 of cycles 1-6. Starting on cycle 7, pembrolizumab monotherapy was continued until disease progression. The primary endpoint was progression-free survival (PFS). Secondary endpoints were safety, tolerability, feasibility, and response rate. Immunohistochemistry (IHC) for PD-L1 and immune infiltrates was analyzed in paired tumor biopsies, as well as bulk transcriptome and exome profiling for five patients and single-cell RNA sequencing for one partial responder.

RESULTS

Eleven patients enrolled, three of whom had received no prior systemic therapy. Treatment was well tolerated, and the most common treatment-related grade 3 or 4 adverse events were lymphocytopenia, anemia, and decreased platelet count. Three patients (27.3%) achieved a partial response, and six (54%) had stable disease. The disease control rate was 81.8%. The median PFS was 4.1 months with a 6-month PFS rate of 45.5%. Molecular profiling suggests qualitative differences in immune infiltration and clonal evolution based on response.

CONCLUSION

Capecitabine and oxaliplatin in combination with pembrolizumab is tolerable and a potentially effective treatment for refractory advanced BTC. This study highlights a design framework for the precise characterization of individual BTC tumors.

TRIAL REGISTRATION

This study was registered in ClinicalTrials.gov (NCT03111732).

Tremelimumab (day 1 only) and durvalumab in combination with transarterial chemoemobilization (TACE) in patients with hepatocellular carcinoma (HCC)

451

Background: TACE induces a peripheral anti-tumor immune response, which may be amplified by immune checkpoint inhibitors (ICI). Combining TACE with dual ICI therapy has been shown to be safe and feasible. Recent data has suggested that Day 1-only anti-CTLA4 dosing could potentially lead to a stronger immune response with a tolerable safety profile though this novel schedule has not previously been combined with TACE. Methods: Patients with HCC (Childs Pugh A/B7, Barcelona clinic liver cancer stage B/C; ECOG 0/1; sorafenib-naive or experienced) were enrolled in a pilot study of tremelimumab at 2 dose levels (DL1: 75mg IV q4-weekly x 4 and DL2: 300mg IV D1 only) in combination with durvalumab (1500mg IV q-28d) and TACE (D36 +/- 96 hours) until progression of disease (per irRECIST) or off-study criteria. Peripheral immune monitoring was performed and tumor biopsies were obtained at time of TACE. Results: 13 patients enrolled on study; N = 3 at DL1 and N = 10 at DL2. M:F 10:3. Median age 70 (65-74). BCLC B/C 4/9. Extrahepatic disease 6/7. Aetiology: NASH (N = 3), alcohol-related disease (N = 1), HCV (N = 2), hemochromatosis (N = 1), unknown (N = 6). 1 patient discontinued due to G3 colitis. All patients evaluable for response with 2/10 patients on DL2 experiencing PR (at 8 weeks) and overall 8/13 SD and 3/13 PD as best response. Updated PFS and OS data to be presented. Conclusions: Tremelimumab (Day 1 only) and Durvalumab in combination with TACE is safe and feasible in patients with HCC. Follow-up is ongoing and full safety and efficacy data will be presented. Clinical trial information: 2019-002767-98.

Recent advances in immune-based approaches for the treatment of esophagogastric cancer

INTRODUCTION

The year 2021 will be remembered as a transformational year in the management of both esophageal and gastric cancers. Decades of failed clinical trials had seen limited therapeutic advances beyond refinement of the traditional combined modality approach. Targeted strategies against specific molecular alterations did not - with the exception of Her2 - yield the desired breakthroughs, and it was unclear what immune-based approaches would bring to this group of cancers. The presence of tumor-infiltrating lymphocytes in esophagogastric cancer demonstrates that an endogenous immune response is already occurring and potentially amplifiable by immune checkpoint inhibition. Recent data have validated this with FDA approvals in both the locoregional (CheckMate 577) and metastatic disease (CheckMate 649, KeyNote 590 and KeyNote 811) setting which have altered the therapeutic landscape.

AREAS COVERED

Here we discuss recent data and ongoing research efforts to better define the role of immune-based approaches and select the patient cohorts who might gain the most benefit from them.

EXPERT OPINION

Immunotherapy, and specifically the incorporation of the immune checkpoint inhibitors (ICI) drug class, has altered the therapeutic paradigm of many cancers in recent years. Anti-PD-1 therapies are now the new standard of care for patients with local and advanced disease.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of hepatocellular carcinoma

Patients with advanced hepatocellular carcinoma (HCC) have historically had few options and faced extremely poor prognoses if their disease progressed after standard-of-care tyrosine kinase inhibitors (TKIs). Recently, the standard of care for HCC has been transformed as a combination of the immune checkpoint inhibitor (ICI) atezolizumab plus the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab was shown to offer improved overall survival in the first-line setting. Immunotherapy has demonstrated safety and efficacy in later lines of therapy as well, and ongoing trials are investigating novel combinations of ICIs and TKIs, in addition to interventions earlier in the course of disease or in combination with liver-directed therapies. Because HCC usually develops against a background of cirrhosis, immunotherapy for liver tumors is complex and oncologists need to account for both immunological and hepatological considerations when developing a treatment plan for their patients. To provide guidance to the oncology community on important concerns for the immunotherapeutic care of HCC, the Society for Immunotherapy of Cancer (SITC) convened a multidisciplinary panel of experts to develop a clinical practice guideline (CPG). The expert panel drew on the published literature as well as their clinical experience to develop recommendations for healthcare professionals on these important aspects of immunotherapeutic treatment for HCC, including diagnosis and staging, treatment planning, immune-related adverse events (irAEs), and patient quality of life (QOL) considerations. The evidence- and consensus-based recommendations in this CPG are intended to give guidance to cancer care providers treating patients with HCC.

Assessing the impact of anti-PD-1/PD-L1 inhibitors on cancer care health and budget in Ireland

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Background: In Ireland, the incidence of cancer was estimated to be 30,272 in 2018 with approximately 9,621 deaths. Over the next five years, the incidence of all cancers is expected to increase by 39% in males and 27% in females. Despite chemotherapy being considered the SOC in many malignancies, it is associated with high levels of toxicity. The introduction of immunotherapy in oncology has revolutionized cancer care, offering improved health outcomes in a range of tumor types. Many treatment options with the potential for use in several cancer types has led to concerns around the long-term affordability of these products. The objective of the study is to estimate and inform current discussion around the potential public health and economic impact of PD-1/PD-L1 inhibitors in Ireland. Methods: The Health Impact Projection (HIP) model estimates the key clinical health and economic outcomes of PD-1/PD-L1 inhibitors in eight high incidence cancers, over a five-year period (2020–2024) compared to the SOC treatments. SOC includes chemotherapy, immuno-oncology treatments not part of the anti PD-1/PD-L1 class (e.g. ipilimumab) and radiotherapy. It includes an assessment of the relative health benefits such as life-years gained, and utility-adjusted life years gained while drawing on budget impact analysis for its structure and methods. The HIP compares the economic and health outcomes in two scenarios; a world without anti PD-1/PD-L1 treatments, to those obtained in a world where patients are treated with a mix of SOC and anti PD-1/PD-L1 treatments. Results: The model shows that over five years, the clinical benefits offered by the introduction of anti PD-1/PD-L1s include an additional 3,194 life-years, 2,411 progression-free life years, 2,638 quality-adjusted life years and the avoidance of 92 adverse events. PD-1/PD-L1 inhibitors produce an average annual budget impact that is equivalent to 0.32% of total healthcare expenditure. Amongst this figure is a reduced burden of indirect costs and end of life costs – both of which fall with anti PD-1/PD-L1s on the market. Conclusions: Ireland faces uncertainty in cancer care with pressure to reduce costs – the HIP helps demonstrate the value of anti PD-1/PD-L1s. Problems stem from a healthcare system that is fragmented and orientated towards dealing with acute conditions. Anti PD-1/PD-L1s are predicted to improve outcomes in Ireland with PFS gains being the largest. In 2020, the budget impact of this class in Ireland is expected to represent a somewhat significant portion of total expenditure on cancer medicines but a small portion of total healthcare expenditure. By projecting budget impact over a five year period, this model should help inform multi-annual budget planning for innovative oncology medicines. This model informs planning by helping quantify the impact of immuno-oncology treatments on health and budget in different scenarios.

Pseudoprogression and cancer immunotherapy: A seven year retrospective study of rate, temporal course, and predictive markers in an Irish tertiary referral center

2651

Background: Immunotherapy is a relatively new treatment strategy which has achieved unprecedented clinical efficacy in many advanced malignancies. However, the pattern of tumour response to immunotherapy is distinct from other therapies and poses major challenges to clinicians. One such challenge is pseudoprogression. The aim of this study was to assess the current management of patients on immunotherapy with radiological evidence of disease progression at first restaging imaging in an Irish cancer centre, and to determine the rate, time course, and predictive markers of pseudoprogression in those patients treated beyond progression (TBP). Methods: Patients treated with immunotherapy for metastatic malignancy in MMUH between March 2013 and September 2020 were retrospectively drawn. Inclusion required follow-up restaging imaging every 4-12 weeks for the duration of treatment. Patterns of response during immunotherapy were established from radiology reports and categorized as stable (SD), response (R), mixed disease (MD), or progressive disease (PD). Pseudoprogression was defined as progression/ mixed disease at first restaging compared to baseline followed by subsequent response/stable disease. Results: The cohort of 228 patients was comprised of 80 NSCLC, 74 melanoma, 25 RCC, 19 gynaecological, 14 gastrointestinal, 6 breast, 1 ESSCLC, and 9 other cancer patients. Median age was 61.16 (IQR 49.47-69.44). Therapeutic agents were anti-PD1 alone (176) or in combination with targeted therapy (6) or CTLA4 (13), CTLA4 alone (15), and anti-PD-L1 alone (13) or in combination with chemotherapy (5). At first restaging, the number (%) classified as SD, R, MD, and PD, respectively, was 29 (12.8), 62 (27.2), 16 (7), and 76 (33.3). Treatment was stopped prior to restaging in 44 (19.3) cases. Of the 92 patients with mixed/ progressive disease, 41 were TBP and 51 were not treated beyond progression (NTBP). Evidence of radiological progression and worsening performance status (PS) were the most common reasons given by clinicians for NTBP. Of those TBP, 20 had subsequent response/stable disease, occurring at a median of 105.50 (range 58.0-420) days after the initial restaging scan and giving an overall pseudoprogression rate of 8.8%. At one year, 100% of the pseudoprogression group was alive. The neutrophil-lymphocyte ratio (NLR) was significantly lower in the pseudoprogression group compared to those with true progression (p = 0.006). There was no significant difference in performance status between the two groups. Conclusions: Pseudoprogression on cancer immunotherapy is real but uncommon, with an overall incidence of 8.8%. It can occur any time up to 420 days after initial progression and indicates a high likelihood of > 1 year survival. A low NLR may be a useful predictor of pseudoprogression but a technological solution is likely needed.

A phase 2 trial of gemcitabine and docetaxel in patients with metastatic colorectal adenocarcinoma with methylated checkpoint with forkhead and ring finger domain promoter and/or microsatellite instability phenotype

Abstract

We previously reported CHFR methylation in a subset of colorectal cancer (CRC; ∼30%) with high concordance with microsatellite instability (MSI). We also showed that CHFR methylation predicted for sensitivity to docetaxel, whereas the MSI‐high phenotypes were sensitive to gemcitabine. We hypothesized that this subset of patients with CRC would be selectively sensitive to gemcitabine and docetaxel. We enrolled a Phase 2 trial of gemcitabine and docetaxel in patients with MSI‐high and/or CHFR methylated CRC. The primary objective was Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 response rate. Enrolled patients were treated with gemcitabine 800 mg/m² on days 1 and 8 and docetaxel 70 mg/m² on day 8 of each 21‐day cycle. A total of 6 patients with CHFR‐methylated, MSI‐high CRC were enrolled from September 2012 to August 2016. The study was closed in September of 2017 due to poor accrual prior to reaching the first interim assessment of response rate, which would have occurred at 10 patients. No RECIST criteria tumor responses were observed, with 3 patients (50%) having stable disease as best response, 1 lasting more than 9 months. Median progression‐free survival (PFS) was 1.79 months (95% confidence interval [CI] = 1.28, not available [NA]) and median overall survival (OS) was 15.67 months (95% CI = 4.24, NA). Common grade 3 toxicities were lymphopenia (67%), leukopenia (33%), and anemia (33%). Although negative, this study establishes a proof‐of‐concept for the implementation of epigenetic biomarkers (CHFR methylation/MSI) as inclusion criteria in a prospective clinical trial to optimize combinatorial strategies in the era of personalized medicine.

Metastatic medullary thyroid carcinoma presenting as ectopic Cushing's syndrome

SUMMARY

A 41-year-old male presented to the Emergency Department with a 6-month history of back and hip pain. Skeletal survey revealed bilateral pubic rami fractures and MRI of the spine demonstrated multiple thoracic and lumbar fractures. Secondary work up for osteoporosis was undertaken. There was no evidence of hyperparathyroidism and the patient was vitamin D replete. Testosterone (T) was low at 1.7 nmol/L (8.6-29.0) and gonadotrophins were undetectable. The patient failed a 1 mg dexamethasone suppression test (DST) with a morning cortisol of 570 nmol/L (<50) and subsequently a low dose DST with a cortisol post 48 h of dexamethasone of 773 nmol/L (<50) and an elevated ACTH 98 ng/L. A corticotropin-releasing factor (CRF) test suggested ectopic ACTH secretion. The patient was commenced on teriparatide for osteoporosis and metyrapone to control the hypercortisolaemia. A positron emission tomography (PET) scan to look for the source of ACTH secretion demonstrated right neck adenopathy. Biopsy and subsequent lymph node dissection were performed and histology revealed a metastatic neuroendocrine tumour. Immunostaining was positive for calcitonin and thyroid transcription factor 1 (TTF1). Serum calcitonin was also significantly elevated at 45 264 ng/L (<10). The patient proceeded to a total thyroidectomy and left neck dissection. Histology confirmed a 7 mm medullary thyroid carcinoma (MTC). Post-operatively, the patient commenced vandetanib therapy and achieved a clinical and biochemical response. After approximately 18 months of vandetanib therapy, the patient developed recurrent disease in his neck. He is currently on LOXO-292 and is doing well 36 months post-diagnosis.

LEARNING POINTS

Unexplained osteoporosis requires thorough investigation and the workup for secondary causes is not complete without excluding glucocorticoid excess. MTC should be considered when searching for sources of ectopic ACTH secretion. Resistance to tyrosine kinase inhibitors is well described with MTC and clinicians should have a low threshold for screening for recurrent disease.

Trial-in-progress: A pilot study of combined immune checkpoint inhibition in combination with ablative therapies in subjects with hepatocellular carcinoma (HCC)

TPS355

Background: Locoregional therapies for hepatocellular carcinoma, such as transcatheter arterial chemoembolization (TACE) or ablation, can induce a peripheral anti-tumor immune response. This may be amplified by immune checkpoint inhibitors (ICI). Early and higher anti-CTLA4 dosing could potentially lead to better priming and a stronger immune response. Recent data has suggested that early (day 1 only), increased doses of anti-CTLA4 therapy, was associated with encouraging clinical activity and a tolerable safety profile. This study will evaluate dual immune checkpoint, CTLA4 (tremelimumab, day 1-only dosing) and PD-L1 (durvalumab) blockade in combination with TACE in patients with advanced HCC. Intensive peripheral immune-monitoring and longitudinal on-treatment tumor biopsies will focus on the role of the innate immune system, particularly Natural Killer cells, in anti-tumor responses. Methods: Patients with HCC (Childs Pugh A/B7; Barcelona Clinic Liver Cancer Stage B/C; ECOG 0/1; sorafenib-naïve or experienced) are being enrolled in a pilot study (Study Number UCDCRC/19/01) of tremelimumab at 2 dose levels (DL1 and DL2) in combination with durvalumab and TACE until disease progression (per irRECIST). DL1: tremelimumab (75mg q28 days for 4 doses) and durvalumab (1500mg q28 days). DL2: tremelimumab (300mg in a single dose on day 1) and durvalumab (1500mg q28 days). Subtotal TACE will be performed during study week 6 with the dose-limiting toxicity (DLT) evaluation period encompassing the first 8 weeks of the study. Primary endpoint is 6-month progression-free survival with secondary efficacy endpoints being safety, tolerability and overall survival. Exploratory objectives will evaluate changes in immune parameters in the tumor and peripheral blood of patients undergoing anti-CTLA4 therapy pre- and post-RFA or TACE. A major focus will be on the role of the innate immune system, particularly Natural Killer cells, in anti-tumor responses. Patients will be enrolled and treated at St Vincent’s University Hospital in Dublin, Ireland. This study is currently open and actively recruiting. Clinical trial information: EudraCT Number 2019-002767-98.

The incidence of Epstein-Barr Virus-associated gastric cancer in an Irish population

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Background: Gastric adenocarcinoma is the fourth most frequent cancer worldwide and the second leading cause of cancer deaths. According to The Cancer Genome Atlas (TCGA) 9% of gastric carcinomas are associated with Epstein-Barr Virus (EBV). EBV- associated gastric carcinoma (EBV-GC) has distinct clinicopathological features, with a marked lymphocytic infiltrate, a generally diffuse histological type and a better prognosis. The immune cell infiltration in EBV-GC suggests a role for immune checkpoint inhibition, which currently has modest activity in unselected gastric cancer. Methods: All cases of gastric or junctional adenocarcinoma diagnosed between Jan 2019 and March 2020 in Mater Misericordiae University Hospital (MMUH) and Jan 2017 and Jan 2019 in Cork University Hospital (CUH) were identified. Electronic medical records were retrospectively reviewed to collect demographic and clinicopathological data such as AJCC TNM stage, tumour subtype and grade, HER-2 status, MMR proficiency and EBV status as determined by EBV-encoded RNA in situ hybridization. Results: N = 103 cases of gastric or junctional adenocarcinoma were identified. 67 male, 36 female, median age 64.5 (range 34 – 95). 40/103 had undergone surgical resection. EBER-ISH was assessed in all patients. 8 of 103 (7.8%) patients showed EBV positivity. These cases were all male patients, median age 62 (range 51-73). The tumours were located as follows; 2 in the cardia, 5 in the body and 1 not documented. The specimens were graded as; 87.5% (7/8) tumours being poorly differentiated and 1/8 moderate to poorly differentiated. The tumour subtypes were specified as; 62.5% (5/8) diffuse, 12.5% (1/8) intestinal and 25% (2/8) mixed intestinal and diffuse. 5/8 patients were locally confined and underwent resection for N0 disease. 3/8 (37.5%) patients had metastatic disease. None of the 8 EBV-GC cases were identified as being HER-2 positive or MMR-deficient. Conclusions: EBV-GC accounted for 7.8% of all gastric cancers in two large tertiary referral centres in Ireland. 37.5% of these patients had metastatic disease. Given this frequency and a possible predictive role in selecting for immunotherapy we conclude that routine assessment of EBV status is feasible in advanced gastric cancer.

A pilot study of avelumab in Epstein-Barr virus-associated gastric cancer

TPS473

Background: Gastric Cancer (GC) is the third most common cause of cancer related deaths worldwide. The median overall survival of patients with stage 4 disease is approximately 1 year. Current accepted treatment approach with chemotherapy is applied with little consideration for known genetic or biologic heterogeneity. Whilst immune-based approaches in GC look promising it is clear that single-agent PD1/PDL1 inhibition benefit a minority. We must clarify a means of identifying prospectively those patients who may benefit from this treatment. A recent landmark paper by The Cancer Genome Atlas (TCGA) proposed a classification of GC into four subtypes: Epstein-Barr-virus (EBV)-positive, microsatellite instable (MSI), chromosomal instable (CI), and genomically stable (GS). Two of the four – EBV and MSI subtypes – are likely to be immunogenic and amenable to PD1/PDL1 inhibition. Recent advances have shown EBV-positive tumors to be infiltrated by lymphocytes and be enriched for PDL1. Methods: This single centre single-arm pilot study in gastric or junctional adenocarcinoma will explore the hypothesis that administering anti-PDL1 therapy (Avelumab) in a prospectively identified population enriched for potential responders will result in improved outcomes. The anticipated frequency of EBV associated-GC (c10%) means that approximately N = 100 patients will be screened to identify N = 10 participants. If a positive signal for efficacy is seen this will provide a basis for a larger, multicentre study. Previously treated Patients with confirmation of stage 4 EBV- positive gastric or oesophago-gastric adenocarcinoma meeting eligibility criteria will be enrolled. Avelumab will be administered at a dose of 10mg/kg IV every 14days. Primary endpoint is to determine the 6-month progression free survival (PFS) of Avelumab in EBV-associated GC. Secondary endpoints include overall response rate, overall survival, median PFS time and feasibility/accrual rate at 12 months. Exploratory endpoints will be to evaluate changes in immune parameters in the peripheral blood over time. Kaplan-Meier methods for primary efficacy endpoint with two-tailed one-sample proportion test will be used to evaluate the evidence to reject the null hypothesis. Clinical trial information: 2018-002085-39.

Immune Checkpoint Blockade in Combination with Stereotactic Body Radiotherapy in Patients with Metastatic Pancreatic Ductal Adenocarcinoma

PURPOSE

The effectiveness of immune checkpoint inhibitors (ICI) is limited in pancreatic ductal adenocarcinoma (PDAC). We conducted a phase I study to evaluate the safety of ICI with stereotactic body radiation therapy (SBRT) in patients with metastatic PDAC.

PATIENTS AND METHODS

Patients enrolled must have received at least one line of prior systemic chemotherapy for metastatic disease. Cohorts A1 and A2 received durvalumab every 2 weeks plus either 8 Gy in one fraction of SBRT on day 1 or 25 Gy in five fractions on day -3 to +1. Cohorts B1 and B2 received durvalumab plus tremelimumab every 4 weeks and either 8 Gy in one fraction of SBRT on day 1 or 25 Gy in five fractions on day -3 to +1. ICIs were continued until unacceptable toxicity or disease progression. The primary objective was the safety and feasibility of treatment. Objective response was assessed in lesions not subjected to SBRT.

RESULTS

Fifty-nine patients were enrolled and 39 were evaluable for efficacy. No dose-limiting toxicities were seen. The most common adverse event was lymphopenia. Two patients achieved a partial response (one confirmed and the other unconfirmed). The overall response rate was 5.1%. Median PFS and OS was 1.7 months [95% confidence intervals (CI), 0.8-2.0 months] and 3.3 months (95% CI, 1.2-6.6 months) in cohort A1; 2.5 months (95% CI, 0.1-3.7 months) and 9.0 months (95% CI, 0.5-18.4 months) in A2; 0.9 months (95% CI, 0.7-2.1 months) and 2.1 months (95% CI, 1.1-4.3 months) in B1; and 2.3 months (95% CI, 1.9-3.4 months) and 4.2 months (95% CI, 2.9-9.3 months) in B2.

CONCLUSIONS

The combination of ICI and SBRT has an acceptable safety profile and demonstrates a modest treatment benefit in patients with metastatic PDAC.

A Pilot Study of the PD-1 Targeting Agent AMP-224 Used With Low-Dose Cyclophosphamide and Stereotactic Body Radiation Therapy in Patients With Metastatic Colorectal Cancer

BACKGROUND

The prognosis of metastatic colorectal cancer (mCRC) is poor. We assessed the feasibility, safety, and efficacy of the anti-programmed cell death 1 fusion protein AMP-224 in combination with low-dose cyclophosphamide and stereotactic body radiation (SBRT) treatment in patients with mCRC refractory to standard chemotherapy.

PATIENTS AND METHODS

Fifteen patients were enrolled. Six received SBRT 8 Gy on day 0 (dose level 1), whereas 9 received 8 Gy on days -2 to day 0. All received cyclophosphamide 200 mg/m² intravenously (I.V.) on day 0. On day 1, both groups received AMP-224 10 mg/kg I.V., repeated every 2 weeks for a total of 6 doses. Primary end points were feasibility and safety.

RESULTS

Ten (67%) patients completed 6 doses of AMP-224; 5 patients (33%) discontinued treatment because of disease progression. No dose-limiting toxicity was observed; 9 patients (60%) experienced treatment-related adverse events, all Grade 1 or 2. No objective response was noted; 3 patients (20%) had stable disease. Median progression-free survival and overall survival were 2.8 months (95% confidence interval [CI], 1.2-2.8 months) and 6.0 months (95% CI, 2.8-9.6 months), respectively. M2 macrophage polarization was present in the pretreatment tumor biopsy samples, but not post-treatment samples.

CONCLUSION

AMP-224 in combination with SBRT and low-dose cyclophosphamide was well tolerated, however, no significant clinical benefit was observed in patients with mCRC.

Tremelimumab in Combination With Microwave Ablation in Patients With Refractory Biliary Tract Cancer

Treatment options for patients with advanced biliary tract cancer are limited. Dysregulation of the immune system plays an important role in the pathogenesis of biliary tract cancer (BTC). This study aimed to investigate whether tremelimumab, an anti-CTLA4 (cytotoxic T-lymphocyte-associated protein 4) inhibitor, could be combined safely with microwave ablation to enhance the effect of anti-CTLA4 treatment in patients with advanced BTC. Patients were enrolled to receive monthly tremelimumab (10 mg/kg, intravenously) for six doses, followed by infusions every 3 months until off-treatment criteria were met. Thirty-six days after the first tremelimumab dose, patients underwent subtotal microwave ablation. Interval imaging studies were performed every 8 weeks. Adverse events (AEs) were noted and managed. Tumor and peripheral blood samples were collected to perform immune monitoring and whole-exome sequencing (WES). Twenty patients with refractory BTC were enrolled (median age, 56.5 years). No dose-limiting toxicities were encountered. The common treatment-related AEs included lymphopenia, diarrhea, and elevated transaminases. Among 16 patients evaluable for efficacy analysis, 2 (12.5%) patients achieved a confirmed partial response (lasting for 8.0 and 18.1 months, respectively) and 5 patients (31.3%) achieved stable disease. Median progression free survival (PFS) and overall survival (OS) were 3.4 months (95% confidence interval [CI], 2.5-5.2) and 6.0 months (95% CI, 3.8-8.8), respectively. Peripheral blood immune cell subset profiling showed increased circulating activated human leukocyte antigen, DR isotype ([HLA-DR] positive) CD8⁺ T cells. T-cell receptor (TCR)β screening showed tremelimumab expanded TCR repertoire, but not reaching statistical significance (P = 0.057). Conclusion: Tremelimumab in combination with tumor ablation is a potential treatment strategy for patients with advanced BTC. Increased circulating activated CD8⁺ T cells and TCR repertoire expansion induced by tremelimumab may contribute to treatment benefit.

The effect of anti-CTLA4 treatment on peripheral and intra-tumoral T cells in patients with hepatocellular carcinoma

BACKGROUND

Checkpoint inhibitors have recently been approved for the treatment of patients with hepatocellular carcinoma (HCC). However, biomarkers, which will help identify patients responding to therapy, are missing. We recently tested the combination of anti-CTLA4 treatment (tremelimumab) with loco-regional therapy in patients with HCC and reported a partial response rate of 26%.

METHODS

Here, we report updated survival analyses and results from our immune monitoring studies on peripheral blood mononuclear cells (PBMCs) and tumors from these patients.

RESULTS

Tremelimumab therapy increased CD4+-HLA-DR+, CD4+PD-1+, CD8+HLA-DR+, CD8+PD-1+, CD4+ICOS+ and CD8+ICOS+ T cells in the peripheral blood of the treated patients. Patients with higher CD4+PD1+ cell frequency at baseline were more likely to respond to tremelimumab therapy. PD-1 expression was increased on alpha fetal protein (AFP) and survivin-specific CD8 T cells upon tremelimumab treatment. An increase of tumor infiltrating CD3+ T cells were also seen in these patients. Immunosequencing of longitudinal PBMC showed that one cycle of tremelimumab significantly decreased peripheral clonality, while no additional effects were seen after loco-regional therapy.

CONCLUSION

In summary, we observed a clear activation of T cell responses in HCC patients treated with tremelimumab and identified potential biomarkers which will help identify patients responding to immunotherapy with anti-CTLA4.

Tremelimumab in combination with microwave ablation in patients with refractory biliary tract cancer (BTC)

365

Background: Treatment option for patients with advanced BTC is limited and prognosis is poor with a median survival of less than 1 year in the locally advanced or metastatic setting. It has been shown deregulation of the immune system plays an important role in the pathogenesis of BTC. This study aimed to investigate whether tremelimumab (Treme), anti-CTLA4, could be combined safely and feasibly with microwave ablation therapy to enhance the effect of anti-CTLA4 treatment in patients with advanced BTC. Methods: Patients with refractory BTC were enrolled in a study of monthly Treme (10mg/kg, IV, 6 doses), followed by 3-monthly infusions until off-treatment criteria were met. On day 36, patients underwent subtotal microwave ablation. Staging image was performed every 8 weeks. Adverse events (AEs) were collected and managed. Tumor samples and peripheral blood samples were collected to perform immune monitoring. Results: Twenty patients with refractory BTC were enrolled. Male: female ratio was 10:10 with median age 56.5 years (range 37-67). Six patients had extrahepatic cholangiocarcinoma (ECC), two patients had gallbladder cancer, whereas the remaining 12 patients had intrahepatic cholangiocarcinoma (ICC). No dose-limiting toxicities were encountered. The common AEs included lymphocytopenia, colitis, adrenal insufficiency, anemia, and elevated transaminases. The most common clinical toxicity was diarrhea. Sixteen patients were evaluable for response analysis, one (6%) patient achieved a confirmed partial response (lasting for 8 months), 6 (37.5%) achieved stable disease with the longest lasting for 9.2 months. Among all 20 patients, median progression free survival, time to progression, and overall survival were 3.4 months (95% CI 2.5-5.2 months), 3.3 months (95% CI: 2.5-4.6 months) and 6.0 months (95% CI 3.8-8.8 months) respectively in this small pilot cohort. T cell receptor (TCR) b screening showed Treme expanded TCR repertoire though non-significantly. RNA seq is ongoing and will be presented. Conclusions: Treme in combination with tumor ablation is a potential new treatment for patients with advanced BTC. TCR repertoire expansion induced by Treme may contribute to treatment benefit. Clinical trial information: NCT01853618.

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

The genomes of cancers deficient in mismatch repair contain exceptionally high numbers of somatic mutations. In a proof-of-concept study, we previously showed that colorectal cancers with mismatch repair deficiency were sensitive to immune checkpoint blockade with antibodies to programmed death receptor-1 (PD-1). We have now expanded this study to evaluate the efficacy of PD-1 blockade in patients with advanced mismatch repair-deficient cancers across 12 different tumor types. Objective radiographic responses were observed in 53% of patients, and complete responses were achieved in 21% of patients. Responses were durable, with median progression-free survival and overall survival still not reached. Functional analysis in a responding patient demonstrated rapid in vivo expansion of neoantigen-specific T cell clones that were reactive to mutant neopeptides found in the tumor. These data support the hypothesis that the large proportion of mutant neoantigens in mismatch repair-deficient cancers make them sensitive to immune checkpoint blockade, regardless of the cancers' tissue of origin.

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

The genomes of cancers deficient in mismatch repair contain exceptionally high numbers of somatic mutations. In a proof-of-concept study, we previously showed that colorectal cancers with mismatch repair deficiency were sensitive to immune checkpoint blockade with antibodies to programmed death receptor-1 (PD-1). We have now expanded this study to evaluate the efficacy of PD-1 blockade in patients with advanced mismatch repair-deficient cancers across 12 different tumor types. Objective radiographic responses were observed in 53% of patients, and complete responses were achieved in 21% of patients. Responses were durable, with median progression-free survival and overall survival still not reached. Functional analysis in a responding patient demonstrated rapid in vivo expansion of neoantigen-specific T cell clones that were reactive to mutant neopeptides found in the tumor. These data support the hypothesis that the large proportion of mutant neoantigens in mismatch repair-deficient cancers make them sensitive to immune checkpoint blockade, regardless of the cancers' tissue of origin.

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers.

Science , this issue p. 409 ; see also p. 358

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

The genomes of cancers deficient in mismatch repair contain exceptionally high numbers of somatic mutations. In a proof-of-concept study, we previously showed that colorectal cancers with mismatch repair deficiency were sensitive to immune checkpoint blockade with antibodies to programmed death receptor-1 (PD-1). We have now expanded this study to evaluate the efficacy of PD-1 blockade in patients with advanced mismatch repair-deficient cancers across 12 different tumor types. Objective radiographic responses were observed in 53% of patients, and complete responses were achieved in 21% of patients. Responses were durable, with median progression-free survival and overall survival still not reached. Functional analysis in a responding patient demonstrated rapid in vivo expansion of neoantigen-specific T cell clones that were reactive to mutant neopeptides found in the tumor. These data support the hypothesis that the large proportion of mutant neoantigens in mismatch repair-deficient cancers make them sensitive to immune checkpoint blockade, regardless of the cancers' tissue of origin.

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers.

Science , this issue p. 409 ; see also p. 358

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers.

Science , this issue p. 409 ; see also p. 358

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade

Colon cancers with loss-of-function mutations in the mismatch repair (MMR) pathway have favorable responses to PD-1 blockade immunotherapy. In a phase 2 clinical trial, Le et al. showed that treatment success is not just limited to colon cancer (see the Perspective by Goswami and Sharma). They found that a wide range of different cancer types with MMR deficiency also responded to PD-1 blockade. The trial included some patients with pancreatic cancer, which is one of the deadliest forms of cancer. The clinical trial is still ongoing, and around 20% of patients have so far achieved a complete response. MMR deficiency appears to be a biomarker for predicting successful treatment outcomes for several solid tumors and indicates a new therapeutic option for patients harboring MMR-deficient cancers.

Science , this issue p. 409 ; see also p. 358

A pilot study of immune checkpoint inhibition in combination with radiation therapy in patients with metastatic pancreatic cancer

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Background: Durvalumab is a human IgG1 monoclonal antibody directed against PD-L1. Tremelimumab is a selective human IgG2 monoclonal antibody against CTLA-4. Several studies have documented an increase in peripheral antitumor immunity following radiation. The hypothesis of this study is that the effect of immune checkpoint inhibition (ICI) can be enhanced by radiation in pancreatic adenocarcinoma (PAC). Methods: Patients with histologically confirmed metastatic PC with primary in-situ or metastatic SBRT-amenable disease are being enrolled to this pilot study. Primary objective to determine safety, tolerability and feasibility of immune checkpoint inhibition [comprising either Durvalumab alone (Cohort A), or combined durvalumab and tremelimumab (Cohort B)] in combination with stereotactic body radiation therapy (SBRT) at two different schedules (8Gy/single fraction or 25Gy in 5 fractions). Select eligibility criteria are as follows: at least 1 measurable metastatic lesion by RECIST 1.1 accessible for biopsy. No limit to the number of prior chemotherapy regimens; ECOG ≤ 1; Life expectancy of greater than 3 months. Acceptable organ and bone marrow function. No active autoimmune disorders. Results: N = 24 patients with chemorefractory metastatic PC have so far been enrolled; M/F = 13/11; Median age = 61. Treatment was well tolerated. No DLT encountered. The most common toxicity was fatigue (G1/2) in all patients in DL2. 5/24 pts had early discontinuation ( < 4 wks) due to rapid PD. No objective responses have been seen. 5 pts (21%) had SD as best response. Conclusions: Immune checkpoint inhibition in combination with SBRT in advanced pancreatic cancer is safe and feasible. Preliminarily no objective responses have been seen for these schedules of SBRT with durvalumab. The study is continuing with evaluation of SBRT with dual checkpoint inhibition (durvalumab and tremelimumab). Clinical trial information: NCT02311361.

Phase I and Preliminary Phase II Study of TRC105 in Combination with Sorafenib in Hepatocellular Carcinoma

Purpose: Endoglin (CD105) is an endothelial cell membrane receptor highly expressed on proliferating tumor vasculature, including that of hepatocellular carcinoma (HCC), and is associated with poor prognosis. Endoglin is essential for angiogenesis, and its expression is induced by hypoxia and VEGF pathway inhibition. TRC105 is a chimeric IgG1 CD105 mAb that inhibits angiogenesis and causes antibody-dependent cellular cytotoxicity and apoptosis of proliferating endothelium.Experimental Design: Patients with HCC (Child-Pugh A/B7), ECOG 0/1, were enrolled in a phase I study of TRC105 at 3, 6, 10, and 15 mg/kg every 2 weeks given with sorafenib 400 mg twice daily. Correlative biomarkers included DCE-MRI and plasma levels of angiogenic factors, including soluble endoglin. Pharmacokinetics were assessed in serum.Results: Twenty-six patients were enrolled, of whom 25 received treatment, 15 with cirrhosis. Hep B/C: 3/15; M:F 19:6; mean age of 60 (range, 18-76); 1 DLT (grade 3 AST) occurred at 10 mg/kg. The most frequent toxicity was low-grade epistaxis, a known toxicity of TRC105. One patient experienced an infusion reaction and was replaced. One patient with coronary stenosis developed a fatal myocardial infarction, and one patient developed G3 cerebral tumor hemorrhage. MTD was not established and DL4 (15 mg/kg) was expanded. The overall response rate in 24 evaluable patients at all 4 dose levels was 21% [95% confidence interval (CI), 7.1-42.2], and 25% (95% CI, 8.7-49.1) in patients with measureable disease. Four patients had confirmed stable disease, one of whom was treated for 22 months. Median progression-free survival (PFS) for 24 patients evaluable for PFS was 3.8 months (95% CI, 3.2-5.6 months); median overall survival was 15.5 months (95% CI, 8.5-26.3 months).Conclusions: TRC105 combined with sorafenib was well tolerated at the recommended single agent doses of both drugs. Encouraging evidence of activity to date (PR rate 25%) was observed, and the study is now continuing to recruit in the phase II stage as a multicenter study to confirm activity of the combination. Clin Cancer Res; 23(16); 4633-41. ©2017 AACR.

Tremelimumab in combination with ablation in patients with advanced hepatocellular carcinoma

BACKGROUND & AIMS

Tremelimumab is a fully human monoclonal antibody that binds to cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) on the surface of activated T lymphocytes. Ablative therapies induce a peripheral immune response which may enhance the effect of anti-CTLA4 treatment in patients with advanced hepatocellular carcinoma (HCC). This study aimed to demonstrate whether tremelimumab could be combined safely and feasibly with ablation.

METHODS

Thirty-two patients with HCC were enrolled: male:female: 28:4; median age: 62 (range 36-76). Patients were given tremelimumab at two dose levels (3.5 and 10mg/kg i.v.) every 4weeks for 6 doses, followed by 3-monthly infusions until off-treatment criteria were met. On day 36, patients underwent subtotal radiofrequency ablation or chemoablation. Staging was performed by contrast-enhanced CT or MRI scan every 8weeks.

RESULTS

No dose-limiting toxicities were encountered. The most common toxicity was pruritus. Of the 19 evaluable patients, five (26.3%; 95% CI: 9.1-51.2%) achieved a confirmed partial response. Twelve of 14 patients with quantifiable HCV experienced a marked reduction in viral load. Six-week tumor biopsies showed a clear increase in CD8⁺ T cells in patients showing a clinical benefit only. Six and 12-month probabilities of tumor progression free survival for this refractory HCC population were 57.1% and 33.1% respectively, with median time to tumor progression of 7.4months (95% CI 4.7 to 19.4months). Median overall survival was 12.3months (95% CI 9.3 to 15.4months).

CONCLUSIONS

Tremelimumab in combination with tumor ablation is a potential new treatment for patients with advanced HCC, and leads to the accumulation of intratumoral CD8⁺ T cells. Positive clinical activity was seen, with a possible surrogate reduction in HCV viral load.

LAY SUMMARY

Studies have shown that the killing of tumors by direct methods (known as ablation) can result in the immune system being activated or switched on. The immune system could potentially also recognize and kill the cancer that is left behind. There are new drugs available known as immune checkpoint inhibitors which could enhance this effect. Here, we test one of these drugs (tremelimumab) together with ablation.

CLINICAL TRIAL NUMBER

ClinicalTrials.gov: NCT01853618.

Tremelimumab: A monoclonal antibody against CTLA-4—In combination with radiofrequency ablation (RFA) in patients with biliary tract carcinoma (BTC)

88

Background: Tremelimumab is a fully human monoclonal antibody that binds to CTLA-4 expressed on the surface of activated T lymphocytes and results in inhibition of B7-CTLA-4-mediated downregulation of T-cell activation. Radiofrequency ablation (RFA) has been shown to induce a peripheral immune response which may enhance the effect of anti-CTLA4 treatment. Methods: Patients with refractory BTC were enrolled in a study of monthly Tremelimumab (10mg/kg, 6 doses) combined with RFA (to one lesion) performed on week 6. Tumor biopsies were performed at time of RFA with regular PBMC collection for intensive immunemontoring. Results: 17 pts enrolled. Characteristics: M:F 8:9; Median age 57(range 36-67); BTC subtype - intrahepatic/exrahepatic: 12/5. 13/17 had metastatic disease. All pts were chemorefractory with 12/17 having received at least 2 regimens. While on study, 6 pts had early PD within 6 weeks; 11 were able to undergo RFA. No DLT encountered. Most common toxicity was pruritus. There were no objective responses. Of evaluable pts N = 6 (55%) had stable disease as a best response. Conclusions: Tremelimumab in combination with subtotal RFA in patients with advanced BTC is safe and feasible. No objective responses have so far been seen in this predominantly primary intrahepatic BTC population. Full efficacy and immune monitoring data will be presented. Clinical trial information: NCT01853618.

Tremelimumab: A monoclonal antibody against CTLA-4—In combination with radiofrequency ablation (RFA) in patients with biliary tract carcinoma (BTC)

316

Background: Tremelimumab is a fully human monoclonal antibody that binds to CTLA-4 expressed on the surface of activated T lymphocytes and results in inhibition of B7-CTLA-4-mediated downregulation of T-cell activation. Radiofrequency ablation (RFA) has been shown to induce a peripheral immune response which may enhance the effect of anti-CTLA4 treatment. Methods: Patients with refractory BTC were enrolled in a study of monthly Tremelimumab (10mg/kg, 6 doses) combined with RFA (to one lesion) performed on week 6. Tumor biopsies were performed at time of RFA with regular PBMC collection for intensive immunemontoring. Results: 17 pts enrolled. Characteristics: M:F 8:9; Median age 57(range 36-67); BTC subtype - intrahepatic/exrahepatic: 12/5. 13/17 had metastatic disease. All pts were chemorefractory with 12/17 having received at least 2 regimens. While on study, 6 pts had early PD within 6 weeks; 11 were able to undergo RFA. No DLT encountered. Most common toxicity was pruritus. There were no objective responses. Of evaluable pts N = 6 (55%) had stable disease as a best response. Conclusions: Tremelimumab in combination with subtotal RFA in patients with advanced BTC is safe and feasible. No objective responses have so far been seen in this predominantly primary intrahepatic BTC population. Full efficacy and immune monitoring data will be presented. Clinical trial information: NCT01853618.

Treating Hepatobiliary Cancer: The Immunologic Approach

Hepatobiliary cancer comprises a heterogeneous group of malignancies in which the standard treatments for advanced disease are minimally effective and evolve slowly over time. Like the majority of gastrointestinal cancers, with some notable exceptions, the impact of immune-based approaches is yet to be experienced. Notwithstanding this, the etiological background of hepatobiliary cancer - overlapping in almost every known causative or associated factor with inflammation - provides a strong clue that these approaches may have an impact on this group of diseases. This review seeks to put the management of hepatobiliary cancers in the context of its inflammation-based etiology, with the aim of pointing to the therapeutic opportunities in immune-based approaches currently entering the clinic or those that are about to do so.

The case for immune-based approaches in biliary tract carcinoma

Biliary tract cancers (BTC) comprise a group of uncommon malignancies in which the standard therapies are minimally effective and evolve slowly. Like the majority of gastrointestinal cancers, with some notable exceptions, the impact of immune-based approaches has yet to be seen. However, the etiological background of BTC-overlapping in almost every known causative or associated factor with inflammation-provides a strong clue that these approaches may have an impact in this group of diseases. This review covers what we currently know about the role of the immune system in the etiology of BTC, highlighting differences by subtype, and pointing to the therapeutic opportunities currently entering the clinic or about to do so. (Hepatology 2016;64:1785-1791).

Modulation of tumor eIF4E by antisense inhibition: A phase I/II translational clinical trial of ISIS 183750-an antisense oligonucleotide against eIF4E-in combination with irinotecan in solid tumors and irinotecan-refractory colorectal cancer

The eukaryotic translation initiation factor 4E (eIF4E) is a potent oncogene that is found to be dysregulated in 30% of human cancer, including colorectal carcinogenesis (CRC). ISIS 183750 is a second-generation antisense oligonucleotide (ASO) designed to inhibit the production of the eIF4E protein. In preclinical studies we found that EIF4e ASOs reduced expression of EIF4e mRNA and inhibited proliferation of colorectal carcinoma cells. An additive antiproliferative effect was observed in combination with irinotecan. We then performed a clinical trial evaluating this combination in patients with refractory cancer. No dose-limiting toxicities were seen but based on pharmacokinetic data and tolerability the dose of irinotecan was reduced to 160 mg/m(2) biweekly. Efficacy was evaluated in 15 patients with irinotecan-refractory colorectal cancer. The median time of disease control was 22.1 weeks. After ISIS 183750 treatment, peripheral blood levels of eIF4E mRNA were decreased in 13 of 19 patients. Matched pre- and posttreatment tumor biopsies showed decreased eIF4E mRNA levels in five of nine patients. In tumor tissue, the intracellular and stromal presence of ISIS 183750 was detected by IHC in all biopsied patients. Although there were no objective responses stable disease was seen in seven of 15 (47%) patients who were progressing before study entry, six of whom were stable at the time of the week 16 CT scan. We were also able to confirm through mandatory pre- and posttherapy tumor biopsies penetration of the ASO into the site of metastasis.

Population attributable fractions of risk factors for hepatocellular carcinoma in the United States

BACKGROUND

Hepatocellular carcinoma (HCC) incidence has been increasing in the United States for several decades; and, as the incidence of hepatitis C virus (HCV) infection declines and the prevalence of metabolic disorders rises, the proportion of HCC attributable to various risk factors may be changing.

METHODS

Data from the Surveillance, Epidemiology, and End Results-Medicare linkage were used to calculate population attributable fractions (PAFs) for each risk factor over time. Patients with HCC (n = 10,708) who were diagnosed during the years 2000 through 2011 were compared with a 5% random sample of cancer-free controls (n = 332,107) residing in the Surveillance, Epidemiology, and End Results areas. Adjusted odds ratios (ORs) and PAFs were calculated for HCV, hepatitis B virus (HBV), metabolic disorders, alcohol-related disorders, smoking, and genetic disorders.

RESULTS

Overall, the PAF was greatest for metabolic disorders (32%), followed by HCV (20.5%), alcohol (13.4%), smoking (9%), HBV (4.3%), and genetic disorders (1.5%). The PAF for all factors combined was 59.5%. PAFs differed by race/ethnicity and sex. Metabolic disorders had the largest PAF among Hispanics (PAF, 39.3%; 95% confidence interval [CI], 31.9%-46.7%) and whites (PAF, 34.8%; 95% CI, 33.1%-36.5%), whereas HCV had the largest PAF among blacks (PAF, 36.1%; 95% CI, 31.8%-40.4%) and Asians (PAF, 29.7%; 95% CI, 25.9%-33.4%). Between 2000 and 2011, the PAF of metabolic disorders increased from 25.8% (95% CI, 22.8%-28.9%) to 36% (95% CI, 33.6%-38.5%). In contrast, the PAFs of alcohol-related disorders and HCV remained stable.

CONCLUSIONS

Among US Medicare recipients, metabolic disorders contribute more to the burden of HCC than any other risk factor, and the fraction of HCC caused by metabolic disorders has increased in the last decade. Cancer 2016;122:1757-65. Published 2016. This article is a U.S. Government work and is in the public domain in the USA..

A pilot study of AMP-224, a PD-L2 Fc fusion protein, in combination with stereotactic body radiation therapy (SBRT) in patients with metastatic colorectal cancer

560

Background: AMP-224, a PD-L2 Fc fusion protein, binds to PD-1, an inhibitory receptor that is present on the cell surface of exhausted, activated, effector, and memory T cells. AMP-224 has a unique mechanism of action in that it binds specifically to PD-1HI T cells (chronically stimulated / exhausted T cells) but not PD-1LO cells which represent the normal activated T cell population. Preclinical studies have documented an increase in antitumor immunity following radiation therapy (RT), but also tumor PD-L1 expression as an escape mechanism. The aim of the study is to evaluate whether inhibition of PD-1/PDL-1 axis could improve anti-tumor immunity effects of RT. Methods: Patients with histologically confirmed metastatic colorectal cancer to liver were treated with SBRT to a site of liver metastasis at 8Gy in a single fraction (DL1) or 8Gy in 3 daily fractions (DL2). All patients received AMP-224 10mg/kg IV beginning Day 1 after SBRT preceded by cyclophosphamide 200mg/m2 (D0). Primary objective was to determine the safety and feasibility of AMP-224 in combination with stereotactic body radiation therapy (SBRT) to metastatic hepatic metastasis in patients with advanced colorectal cancer. Mandatory pre- and post-treatment biopsies were attempted on all patients. Results: N = 17 patients with refractory metastatic CRC were enrolled. N = 2 pts were unevaluable. 6pts were treated at DL1 (8Gy x 1fraction SBRT, AMP-224 10mg/kg q2-weekly) and 9pts were treated at DL2 (8Gy x 3fractions SBRT, AMP-224 10mg/kg q2-weekly) No DLT was encountered. The most common toxicity was fatigue (G1/2) in all patients in DL2. N = 3 patients experienced G2 infusion reaction which responded to standard interventions. 5/15 pts did not complete treatment due to rapid PD. No objective responses have been seen, although N = 6 pts remain on study. Pre- and post-tumor biopsies were performed on 7 of first 11 pts. Conclusions: AMP-224 in combination with SBRT to site of colorectal hepatic metastases is safe and feasible. Preliminarily no objective responses have been seen. Full clinical and correlative data including post-therapeutic radiated and non-radiated tumor biopsies will be presented. Clinical trial information: NCT02298946.

Tremelimumab, a monoclonal antibody against CTLA-4, in combination with subtotal ablation (trans-catheter arterial chemoembolization [TACE], radiofrequency ablation [RFA] or cryoablation) in patients with hepatocellular carcinoma (HCC) and biliary tract carcinoma (BTC)

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Background: Tremelimumab is a fully human monoclonal antibody that binds to CTLA-4 expressed on the surface of activated T lymphocytes and results in inhibition of B7-CTLA-4-mediated downregulation of T-cell activation. Transcatheter arterial chemoembolization (TACE), radiofrequency ablation (RFA) and cryoablation (CA) have been shown to induce a peripheral immune response which may enhance the effect of anti-CTLA4 treatment in patients with advanced HCC. Methods: Patients with HCC [Childs Pugh A/B7; BCLC B/C; ECOG 0/1; post-sorafenib (BCLC stage C only)] or refractory BTC were enrolled in a study of Tremelimumab combined with subtotal TACE, RFA or CA performed on week 6. All BTC patients received RFA as the immune-stimulant in combination with tremelimumab. Tumor biopsies were performed at baseline and at time of RF/TACE. Results: 34 pts enrolled (28 HCC, 6 BTC). Characteristics: M:F 26:8; Median age 54(range 42-76); In HCC pts cirrhosis present in 17pts, BCLC Stage B/C: 9/19; Hepatitis B/C/neg: 4/15/9. 13 pts received TACE, 16 underwent RFA (inc 6 BTC pts), 3 CA during week 6 of tremelimumab therapy. 2 pts did not receive an ablative procedure. No DLT encountered. Most common toxicity was pruritus. One patient developed pulmonitis and was taken off study but remained disease-free at 16m. Of N = 17 pts evaluable for response outside of TACE/RFA-treated lesion 4 (23.5%) achieved confirmed partial responses. 8 of 9 pts with quantifiable HCV experienced a marked reduction in viral load. 6-week tumor biopsies showed immune cell infiltration on all evaluable patients. Median PFS for the evaluable HCC population (N = 25) was 5.7m. Conclusions: Tremelimumab in combination with subtotal TACE, RFA or CA in patients with advanced HCC and BTC is safe and feasible. Obtaining tumor biopsies at baseline and at the time of RFA/TACE is safe. Evidence of immune cell infiltration was seen on evaluable patients. Encouraging clinical activity seen with objective confirmed responses, PFS 5.7m and possibly surrogate reductions in HCV viral load. Clinical trial information: NCT01853618.

A pilot study of immune checkpoint inhibition (tremelimumab and/or MEDI4736) in combination with radiation therapy in patients with unresectable pancreatic cancer

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Background: Tremelimumab is a fully human monoclonal antibody that binds to CTLA-4 expressed on the surface of activated T lymphocytes and causes inhibition of B7-CTLA-4-mediated downregulation of T-cell activation. MEDI4736 is a human monoclonal antibody directed against PD-L1. Blockage of ligation between PD-L1 and PD1 induces local immune activation and prevents anergy and exhaustion of effector T-cells. Several studies have documented an increase in peripheral antitumor immunity following radiation. This effect is evidently too weak to be clinically relevant, but has the potential to be boosted by immune modulation. The underlying hypothesis of this study is that the effect of immune checkpoint inhibition (accomplished via tremelimumab and/or MEDI4736) treatment can be enhanced by radiation in patients with advanced pancreatic carcinoma. Whilst radiation treatment in pancreas cancer is commonly employed in limited or early stage disease, if radiation can enhance the effect of immune checkpoint inhibition to produce systemic anti-tumor effects the combination could become an effective treatment modality for patients with advanced disease. Methods: Patients with histologically confirmed metastatic pancreatic cancer with primary in-situ (or locally-recurrent) disease are being enrolled to this pilot study. The primary objectives are to determine the safety, tolerability and feasibility of immune checkpoint inhibition [comprising either MEDI4736 alone (Cohort A), Tremelimumab (Cohort B) or combined MEDI4736 and Tremelimumab (Cohort C)] in combination with stereotactic body radiation therapy (SBRT) in patients with unresectable pancreatic cancer. Select eligibility criteria are as follows: at least 1 measurable metastatic lesion by RECIST 1.1 criteria and accessible for biopsy. No prior radiation therapy to the pancreas allowed. There is no limit to the number of prior chemotherapy regimens received; ECOG ≤ 1; Life expectancy of greater than 3 months. Acceptable organ and bone marrow function. No active or prior documented autoimmune or inflammatory disorders. Clinical trial information: NCT02311361.

Pancreatic squamous cell carcinoma: Epidemiology, clinicopathologic characteristics, and outcomes

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Background: Although squamous metaplasia is commonly detected in pancreatic parenchyma, primary pancreatic squamous cell carcinoma (SCC) is a rare malignancy with unknown incidence and unclear prognosis. Methods: Using SEER-18 database primary code C25 in conjunction with histology codes for SCC (8052-8053, 8070-8078, 8083-8084) and for adenocarcinoma (AC) (8052-8053, 807-8078, 8083-8084), we identified cases diagnosed from 2000 to 2012. Age-adjusted incidence rates and trends over time were calculated. Patients with SCC were compared with AC by clinical features (TNM categories and histological differentiation), and 1-year and 2-year relative survival (RS) outcomes. Chi-square tests for categorical variables and t-tests for continuous variables were conducted. Kaplan-Meier method was used to estimate RS and Z-test was used to compare RS rates. SEERStat and GraphPad were used for analysis. Results: We identified 214 patients with microscopically confirmed SCC and 72,860 patients with AC. SCC constituted less than 1% of all cases of primary pancreatic cancer; however, age-adjusted incidence rates for this subtype tripled between 2000 and 2012. The annual percent increase of SCC incidence rate was 5.5%. Significant differences were observed by age, gender and race: older age groups, blacks and males had higher SCC incidence rates. Compared to AC, a greater proportion of patients with SCC had poorly differentiated histology (15.8% vs. 30.4%, p < 0.01). Similar to AC, the majority of patients with SCC had stage IV disease at diagnosis, 54.3% for AC vs. 56.4% SCC. The 1-year and 2-year relative survival rates were significantly lower in patients with SCC than AC. The 1-year relative survival rate was 15.8% (95%CI = 10.4-22.3) for SCC, compared with 24.7% (95%CI = 24.3-25.1) for AC, p < 0.001. Conclusions: Although primary squamous pancreatic carcinoma is a rare neoplasm, incidence rates for this subtype are markedly rising. Relative to adenocarcinoma, pancreatic squamous cell carcinoma is characterized by poorly differentiated histology and worse survival.

A phase II study of TRC105 in patients with hepatocellular carcinoma who have progressed on sorafenib

BACKGROUND

Endoglin is an endothelial cell membrane receptor essential for angiogenesis and highly expressed on the vasculature of many tumor types, including hepatocellular carcinoma (HCC). TRC105 is a chimeric IgG1 anti-CD105 monoclonal antibody that inhibits angiogenesis and tumor growth by endothelial cell growth inhibition, ADCC and apoptosis, and complements VEGF inhibitors.

OBJECTIVE

The aim of this phase II study was to evaluate the efficacy of anti-endoglin therapy with TRC105 in patients with advanced HCC, post-sorafenib.

METHODS

Patients with HCC and compensated liver function (Childs-Pugh A/B7), ECOG 0/1, were enrolled to a single-arm, phase II study of TRC105 15 mg/kg IV every two weeks. Patients must have progressed on or been intolerant of prior sorafenib. A Simon optimal two-stage design was employed with a 50% four-month PFS target for progression to the second stage. Correlative biomarkers evaluated included DCE-MRI as well as plasma levels of angiogenic biomarkers and soluble CD105.

RESULTS

A total accrual of 27 patients was planned. However, because of lack of efficacy and in accordance with the Simon two-stage design, 11 patients were enrolled. There were no grade 3/4 treatment-related toxicities. Most frequent toxicities were headache (G2; N = 3) and epistaxis (G1; N = 4). One patient had a confirmed partial response by standard RECIST criteria and biologic response on DCE-MRI but the four-month PFS was insufficient to proceed to the second stage of the study.

CONCLUSIONS

TRC105 was well tolerated in this HCC population following sorafenib. Although there was evidence of clinical activity, this did not meet prespecified criteria to proceed to the second stage. TRC105 development in HCC continues as combination therapy with sorafenib.

Colorectal Cancer Survival Gains and Novel Treatment Regimens: A Systematic Review and Analysis

IMPORTANCE

The past 2 decades have witnessed progress in the management of metastatic colorectal cancer (mCRC) with more effective agents and better surgical, medical, and supportive care. While substantial progress has been made, much more must be achieved to prolong the lives of patients.

OBJECTIVE

To conduct a systematic review to ascertain what percentage of the life expectancy gain in locally advanced and mCRC over the past 2 decades is due to novel therapies vs improvements in supportive care or secular trends and to thus inform treatment development strategies.

EVIDENCE REVIEW

We searched Cochrane Controlled Trials Register, Medline, Embase, CancerLit, and Healthstar electronic databases for trials covering the period 1993 to 2015, scanned reference lists of articles, and searched recent conference abstracts. Ninety-six phase 3 trials and large (>50 patients) phase 2 trials in mCRC were examined. Outcomes evaluated in the experimental arms (EAs) and control arms (CAs) included overall response rate, stable disease, progression-free survival (PFS), and overall survival (OS).

FINDINGS

Over the period covered by the studies, the OS in EAs increased at a mean (95% CI) rate of 0.80 (0.67-0.93) mo/y. Importantly, OS in the CAs improved 0.63 (0.51-0.75) mo/y, reflecting in part the use of experimental regimens in subsequent studies. Chemotherapy contributed only partly to the gains in OS, given that (1) mean (95% CI) improvements in PFS were only 0.31 (0.22-0.39) mo/y in the EAs and 0.23 (0.15-0.31) mo/y in CAs; (2) gains in survival not directly attributable to the protocol were greater than gains in PFS (0.46 [0.36-0.57] mo/y in EAs and 0.39 [0.29-0.49] mo/y in CAs; and (3) effects on OS were much lower in second-line trials (median [interquartile range] response rates, 8.6% [0%-11.0%] in EAs and 7.5% [3.8%-12.8%] in CAs) compared with first-line trials (39.5% [24.0%-50.2%] for EAs and 29.4% [16.4%-39.4%] for CAs).

CONCLUSIONS AND RELEVANCE

The OS of patients with mCRC has improved gradually over the past 2 decades, with gains from chemotherapy occurring alongside gains from lead-time bias and improved locoregional approaches and supportive care. Gains from first-line therapies have been modest but consistent; however, gains from second-line therapies have been disappointing. We believe that future progress will be greater if emphasis is placed on enrolling patients in experimental trials to explore and develop alternative first-line regimens and better second-line therapies.

The yin and yang of evasion and immune activation in HCC

Current systemic treatment options for patients with hepatocellular carcinoma (HCC) are limited to sorafenib. With the recent FDA approval of the second PD1-PD-L1 pathway inhibitor, immunotherapy has gained even more interest as a potential novel treatment option for patients with HCC. This is due not only because of the failure of other treatment approaches in the past, but also because immunological mechanisms have been shown to play an important role during tumor development, growth, and treatment. Here we present a review of immunological mechanisms in the liver relevant for tumor progression and treatment. We summarize our current knowledge on immune activating and immune suppressing mechanisms during tumor initiation, development, and treatment. We try to explain the paradox of how inflammatory responses in a setting of chronic infection promote tumor development, while the primary aim of immunotherapy is to activate immunity. Finally we summarize recent advances in addition to providing an outlook for the immunotherapy of HCC.