Regulatory role of CD39 and CD73 in tumor immunity.

CD39 is the rate-limiting enzyme for the molecular signal cascade leading to the generation of ADP and adenosine monophosphate (AMP). In conjunction with CD73, CD39 converts adenosine triphosphate (ATP) to ADP and AMP, which leads to the accumulation of immunosuppressive adenosine in the tumor microenvironment. This review focuses on the role of CD39 and CD73 in immune response and malignant progression, including the expression of CD39 within the tumor microenvironment and its relationship to immune effector cells, and its role in antigen presentation. The role of CD39- and CD73-targeting therapeutics and cancer-directed clinical trials investigating CD39 modulation are also explored.

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Targeted Combination of Poly(ADP-ribose) Polymerase Inhibitors and Immune Checkpoint Inhibitors Lacking Evidence of Benefit: Focus in Ovarian Cancer.

The emergence of targeted therapeutics in ovarian cancer, particularly poly (ADP-ribose) polymerase inhibitors (PARPi's), has created additional opportunities for patients seeking frontline and recurrent disease management options. In particular, PARPi's have shown clinical benefits in BRCA mutant and/or homologous recombination deficient (HRD) ovarian cancer. Until recently, response was thought to be limited in BRCA wild-type, homologous recombination proficient (HRP) cancers. Therefore, attempts have been made at combination therapy involving PARPi to improve patient outcomes. Additionally, immune checkpoint inhibitors (ICIs) have demonstrated underwhelming results involving ovarian cancer. Many are searching for reliable biomarkers of immune response to increase efficacy of ICI therapy involving ovarian cancer. In this review, we examine the evidence supporting the combination of PARPi and ICIs in ovarian cancer, which is still lacking.

Homologous recombination proficiency in ovarian and breast cancer patients.

Homologous recombination and DNA repair are important for genome maintenance. Genetic variations in essential homologous recombination genes, including BRCA1 and BRCA2 results in homologous recombination deficiency (HRD) and can be a target for therapeutic strategies including poly (ADP-ribose) polymerase inhibitors (PARPi). However, response is limited in patients who are not HRD, highlighting the need for reliable and robust HRD testing. This manuscript will review BRCA1/2 function and homologous recombination proficiency in respect to breast and ovarian cancer. The current standard testing methods for HRD will be discussed as well as trials leading to approval of PARPi's. Finally, standard of care treatment and synthetic lethality will be reviewed.

Gemogenovatucel-T (Vigil) maintenance immunotherapy: 3-year survival benefit in homologous recombination proficient (HRP) ovarian cancer.

OBJECTIVE: Previously, Vigil demonstrated clinical benefit to prolong relapse free and overall survival in the BRCA wild-type (BRCA-wt), homologous recombination proficient (HRP) patient population. Here we provide long term follow up of 3 years in the HRP patient population enrolled in the Phase 2b VITAL study. METHODS: HRP patients treated with Vigil (n = 25) or placebo (n = 20) who were enrolled in the Phase 2b, double-blind, placebo-controlled (VITAL study, NCT02346747) were followed for safety, OS and RFS. OS and RFS from time of randomization (immediately prior to maintenance therapy) and from debulking tissue procurement time points were analyzed by Kaplan-Meier (KM) and restricted mean survival time (RMST) analysis. RESULTS: OS for Vigil treated patients at 3 years has not yet reached median OS time point (95% CI 41.6 months to not achieved) compared to 26.9 (95% CI 17.4 months to not achieved) in placebo treated patients (HR 0.417 p = 0.020). Three year RFS also showed benefit to Vigil (stratified HR 0.405, p = 0.011) and no long term toxicity to Vigil was observed. Three year OS for Vigil of 70% vs. 40% for placebo from time of randomization was observed (p = 0.019). RMST analysis was also significant for OS (45.7 vs. 32.8 months, p = 0.008) and RFS (p = 0.025). CONCLUSION: In conclusion, results suggest durable activity of Vigil on RFS and OS and support further evaluation of Vigil in HRP ovarian cancer.

Gemogenovatucel-T (Vigil) immunotherapy demonstrates clinical benefit in homologous recombination proficient (HRP) ovarian cancer.

OBJECTIVE: Recently, Vigil showed significant clinical benefit with improvement in relapse free (RFS) and overall survival (OS) in pre-planned subgroup analysis in stage III/IV newly diagnosed ovarian cancer patients with BRCA wild type (BRCA-wt) molecular profile. Here we analyze homologous recombination (HR) status of patients enrolled in the Phase 2b VITAL study and determine clinical benefit of Vigil in HR proficient (P) patients. METHODS: Patients were previously enrolled in a Phase 2b, double-blind, placebo-controlled trial. All were in complete response with Stage III/IV high grade serious, endometroid or clear cell ovarian cancer. HR status was determined using MyChoice®CDx score (<42 = HRP) (Myriad Genetics, Inc., UT). Post-hoc analyses were carried out using Kaplan Meier and restricted mean survival time (RMST) analysis to evaluate RFS and OS based on HR deficiency (D) status. RESULTS: RFS was improved with Vigil (n = 25) in HRP patients compared to placebo (n = 20) (HR = 0.386; 90% CI 0.199-0.750; p = 0.007), results were verified by RMST (p = 0.017). Similarly, OS benefit was observed in Vigil group compared to placebo (HR = 0.342; 90% CI 0.141-0.832; p = 0.019). Results with OS were also verified with RMST (p = 0.008). CONCLUSION: Vigil exhibited clinical benefit in HRP molecular profile patients.

BRCA1/2 signaling and homologous recombination deficiency in breast and ovarian cancer.

Patients who have mutations of the genes BRCA1 or BRCA2 are at an increased risk for developing breast and ovarian cancer. BRCA1/2 function as tumor suppressor genes, responsible for regulating DNA repair, and play an essential role in homologous recombination. Mutation of BRCA1/2 results in homologous recombination deficiency and genomic instability which drives oncogenesis and cancer proliferation. Recently, BRCA1/2 gene expression has been implicated in regulating immune response. Here we discuss the signaling pathway of BRCA1/2 in relation to breast and ovarian cancer, with emphasis on how dysregulation facilitates the path to malignancy and current treatment options.

The abscopal effect of radiation therapy.

Radiation therapy (RT) in some cases results in a systemic anticancer response known as the abscopal effect. Multiple hypotheses support the role of immune activation initiated by RT-induced DNA damage. Optimal radiation dose is necessary to promote the cGAS-STING pathway in response to radiation and initiate an IFN-1 signaling cascade that promotes the maturation and migration of dendritic cells to facilitate antigen presentation and stimulation of cytotoxic T cells. T cells then exert a targeted response throughout the body at areas not subjected to RT. These effects are further augmented through the use of immunotherapeutic drugs resulting in increased T-cell activity. Tumor-infiltrating lymphocyte presence and TREX1, KPNA2 and p53 signal expression are being explored as prognostic biomarkers.

Ovarian Cancer Immunotherapy and Personalized Medicine.

Ovarian cancer response to immunotherapy is limited; however, the evaluation of sensitive/resistant target treatment subpopulations based on stratification by tumor biomarkers may improve the predictiveness of response to immunotherapy. These markers include tumor mutation burden, PD-L1, tumor-infiltrating lymphocytes, homologous recombination deficiency, and neoantigen intratumoral heterogeneity. Future directions in the treatment of ovarian cancer include the utilization of these biomarkers to select ideal candidates. This paper reviews the role of immunotherapy in ovarian cancer as well as novel therapeutics and study designs involving tumor biomarkers that increase the likelihood of success with immunotherapy in ovarian cancer.

Gemogenovatucel-T (Vigil) immunotherapy as maintenance in frontline stage III/IV ovarian cancer (VITAL): a randomised, double-blind, placebo-controlled, phase 2b trial.

BACKGROUND: Gemogenovatucel-T is an autologous tumour cell vaccine manufactured from harvested tumour tissue, which specifically reduces expression of furin and downstream TGF-ß1 and TGF-ß2. The aim of this study was to determine the safety and efficacy of gemogenovatucel-T in front-line ovarian cancer maintenance. METHODS: This randomised, double-blind, placebo-controlled, phase 2b trial involved 25 hospitals in the USA. Women aged 18 years and older with stage III/IV high-grade serous, endometrioid, or clear cell ovarian cancer in clinical complete response after a combination of surgery and five to eight cycles of chemotherapy involving carboplatin and paclitaxel, and an Eastern Cooperative Oncology Group status of 0 or 1 were eligible for inclusion in the study. Patients were randomly assigned (1:1) to gemogenovatucel-T or placebo by an independent third party interactive response system after successful screening using randomly permuted block sizes of two and four and stratified by extent of surgical cytoreduction and neoadjuvant versus adjuvant chemotherapy. Gemogenovatucel-T (1 × 107 cells per injection) or placebo was administered intradermally (one per month) for a minimum of four and up to 12 doses. Patients, investigators, and clinical staff were masked to patient allocation until after statistical analysis. The primary endpoint was recurrence-free survival, analysed in the per-protocol population. All patients who received at least one dose of gemogenovatucel-T were included in the safety analysis. The study is registered with ClinicalTrials.gov, NCT02346747. FINDINGS: Between Feb 11, 2015, and March 2, 2017, 310 patients consented to the study at 22 sites. 217 were excluded. 91 patients received gemogenovatucel-T (n=47) or placebo (n=44) and were analysed for safety and efficacy. The median follow-up from first dose of gemogenovatucel-T was 40·0 months (IQR 35·0-44·8) and from first dose of placebo was 39·8 months (35·5-44·6). Recurrence-free survival was 11·5 months (95% CI 7·5-not reached) for patients assigned to gemogenovatucel-T versus 8·4 months (7·9-15·5) for patients assigned to placebo (HR 0·69, 90% CI 0·44-1·07; one-sided p=0·078). Gemogenovatucel-T resulted in no grade 3 or 4 toxic effects. Two patients in the placebo group had five grade 3 toxic events, including arthralgia, bone pain, generalised muscle weakness, syncope, and dyspnea. Seven patients (four in the placebo group and three in the gemogenovatucel-T group) had 11 serious adverse events. No treatment-related deaths were reported in either of the groups. INTERPRETATION: Front-line use of gemogenovatucel-T immunotherapy as maintenance was well tolerated but the primary endpoint was not met. Further investigation of gemogenovatucel-T in patients stratified by BRCA mutation status is warranted. FUNDING: Gradalis.

Molecular mechanisms underlying rheumatoid arthritis and cancer development and treatment.

Given recent advances in cancer immune therapy, specifically use of checkpoint inhibitors, understanding the link between autoimmunity and cancer is essential. Rheumatoid arthritis (RA) affects about 1% of the population, and early diagnosis is key to prevent joint damage. Management consists of disease-modifying antirheumatic drugs that alter normal immunologic pathways, which could affect malignancy growth and survival. Prolonged immune dysregulation and the resulting inflammatory response associated with development of RA may also lead to increased cancer development risk. RA has long been associated with increased risk of non-Hodgkin's lymphoma [1] and further evidence supports relationship to lung cancer [2]. This review will address the mechanisms behind cancer development and progression in RA patients, biomarkers and assess cancer risk and early detection.

Bifidobacterium spp: the promising Trojan Horse in the era of precision oncology.

Selective delivery of therapeutic agents into solid tumors has been a major challenge impeding the achievement of long-term disease remission and cure. The need to develop alternative drug delivery routes to achieve higher drug concentration in tumor tissue, reduce unwanted off-target side effects and thus achieve greater therapeutic efficacy, has resulted in an explosive body of research. Bifidobacterium spp. are anaerobic, nonpathogenic, Gram-positive bacteria, commensal to the human gut that are a possible anticancer drug-delivery vehicle. In this review, we describe Bifidobacterium's microbiology, current clinical applications, overview of the preclinical work investigating Bifidobacterium's potential to deliver anticancer therapy, and review the different strategies used up to date. Finally, we discuss both current challenges and future prospects.

3D engineered scaffold for large-scale Vigil immunotherapy production.

Previously, we reported successful cellular expansion of a murine colorectal carcinoma cell line (CT-26) using a three-dimensional (3D) engineered extracellular matrix (EECM) fibrillar scaffold structure. CCL-247 were grown over a limited time period of 8 days on 3D EECM or tissue culture polystyrene (TCPS). Cells were then assayed for growth, electroporation efficiency and Vigil manufacturing release criteria. Using EECM scaffolds, we report an expansion of CCL-247 (HCT116), a colorectal carcinoma cell line, from a starting concentration of 2.45 × 105 cells to 1.9 × 106 cells per scaffold. Following expansion, 3D EECM-derived cells were assessed based on clinical release criteria of the Vigil manufacturing process utilized for Phase IIb trial operation with the FDA. 3D EECM-derived cells passed all Vigil manufacturing release criteria including cytokine expression. Here, we demonstrate successful Vigil product manufacture achieving the specifications necessary for the clinical trial product release of Vigil treatment. Our results confirm that 3D EECM can be utilized for the expansion of human cancer cell CCL-247, justifying further clinical development involving human tissue sample manufacturing including core needle biopsy and minimal ascites samples.

Folate Receptor as a Biomarker and Therapeutic Target in Solid Tumors.

Folate is a B vitamin necessary for basic biological functions, including rapid cell turnover occurring in cancer cell proliferation. Though the role of folate as a causative versus protective agent in carcinogenesis is debated, several studies have indicated that the folate receptor (FR), notably subtype folate receptor alpha (FRα), could be a viable biomarker for diagnosis, progression, and prognosis. Several cancers, including gastrointestinal, gynecological, breast, lung, and squamous cell head and neck cancers overexpress FR and are currently under investigation to correlate receptor status to disease state. Traditional chemotherapies have included antifolate medications, such as methotrexate and pemetrexed, which generate anticancer activity during the synthesis phase of the cell cycle. Increasingly, the repertoire of pharmacotherapies is expanding to include FR as a target, with a heterogenous pool of directed therapies. Here we discuss the FR, expression and effect in cancer biology, and relevant pharmacologic inhibitors.

Clonal Neoantigen: Emerging "Mechanism-based" Biomarker of Immunotherapy Response.

Clonal mutations represent the initiating molecular defects related to cellular transition of a normal phenotype to a malignant phenotype. Molecular genomic assessment utilizing next generation and whole exome sequencing is now being increasingly applied to biomarker determination to refine the use of targeted immune therapies. Case examples followed by retrospective study assessment have convincingly demonstrated clonal neoantigens provide a relevant predictor of response to checkpoint inhibition. A meta-analysis, by Litchfield et al., of over 1000 cancer patients from 12 landmark trials demonstrated no clinical benefit to checkpoint inhibitor (CPI) therapy in correlation to high subclonal tumor mutational burden (TMB), whereas high clonal TMB was found to be significantly correlated with better overall survival (p = 0.000000029). We discuss the mechanism of clonal vs. subclonal neoantigen targeting relationship to homologous recombination proficient (HRP) profile, evidence of preclinical and clinical benefit related to clonal neoantigens, and review a novel developing therapy called Vigil®, designed to expand the clonal neoantigen targeting effector cell populations. Vigil® is an autologous cellular immunotherapy which is designed to carry the full set of personal clonal neoantigens. Phase 2b results demonstrate a durable recurrence-free survival (RFS) and overall survival (OS) advantage for Vigil® in a subset ovarian cancer population with an HRP cancer profile.

Advances in Targeted Therapy for the Treatment of Cervical Cancer.

Cervical cancer is an international public health crisis, affecting several hundred thousand women annually. While not universally protective due to other risk factors, many such cases are preventable with vaccination against high-risk serotypes of the human papilloma virus (HPV 6, 11, 16, 18, 31, 33, 45, 53, 58). Advanced-stage and recurrent cervical cancers are typically lethal and have been the focus in recent years of the integration of immune checkpoint inhibitors (CPIs) to improve survival. We have consolidated information regarding the role of the immune system in both disease progression and disease clearance with the aid of targeted therapies and immunotherapeutic agents. Additionally, we have characterized the treatment modalities currently indicated as the standard of care-such as bevacizumab and the immune CPIs-and those recently approved or in development, including Tivdak, Vigil, and chimeric antigen receptor (CAR) T-cells.

Pilot Study of Recurrent Ewing's Sarcoma Management with Vigil/Temozolomide/Irinotecan and Assessment of Circulating Tumor (ct) DNA.

PURPOSE: Treatment options for recurrent or refractory Ewing's sarcoma (ES) are limited. Vigil is a novel autologous tumor cell therapy expressing bi-shRNA furin/GMCSF plasmid, which previously demonstrated monotherapy activity in advanced ES. Herein we report safety and evidence of benefit to Vigil for ES as potential treatment. PATIENTS AND METHODS: In this pilot trial, eligible patients with recurrent or refractory ES who failed initial standard-of-care therapy received treatment with temozolomide (TEM) 100 mg/m2/day oral and irinotecan (IRI) 50 mg/m2/day oral, Days 1 to 5, in combination with Vigil (1 × 106-107 cells/mL/day intradermal, Day 15), every 21 days (Vigil/TEM/IRI). Objective response rate (ORR) by RECIST v1.1, progression-free survival (PFS), and overall survival (OS) were assessed. Circulating tumor (ct) DNA analysis was done by patient-specific droplet digital PCR on baseline and serially collected on-treatment samples. RESULTS: Eight of 10 enrolled patients were evaluable for safety and efficacy (mean age 24.6; 12.6-46.1 years old); 2 did not receive Vigil. Seven of 8 patients previously received TEM/IRI. No Vigil-related adverse events were reported. Common ≥Grade 3 chemotherapy-related toxicity included neutropenia (50%) and thrombocytopenia (38%). We observed two partial response patients by RECIST; both showed histologic complete response without additional cancer therapy. Median PFS was 8.2 months (95% confidence interval, 4.3-NA). Five patients showed stable disease or better for ≥6 months. Patient-specific EWS/FLI1 ctDNA was detectable in all 8 evaluable patients at baseline. Changes in ctDNA levels corresponded to changes in disease burden. CONCLUSIONS: Results demonstrated safety of combination Vigil/TEM/IRI.

Steps solidifying a role for SEPT9 in breast cancer suggest that greater strides are needed.

Septins comprise a conserved family of GTPase proteins. Of these, human SEPT9 has been widely implicated in cancers of epithelial origin, including breast cancer, as well as leukemia. In a previous issue of Breast Cancer Research, Connolly and colleagues present compelling data further supporting a role for SEPT9 isoforms in early breast cancer development as well as evidence suggesting that cellular localization patterns of SEPT9 isoforms may contribute to oncogenesis.

SEPT9_i1 and genomic instability: mechanistic insights and relevance to tumorigenesis.

Septins are highly conserved cytoskeletal GTP-binding proteins implicated in numerous cellular processes from apoptosis to vesicle trafficking. Septins have been associated with leukemia and solid tumor malignancies, including breast, ovarian, and prostate. We previously reported that high SEPT9_i1 expression in human mammary epithelial cell lines (HMECs) led to malignant cellular phenotypes such as increased cell proliferation, invasiveness, motility, and genomic instability. Our goal here was to better understand how SEPT9_i1 expression might contribute to genomic instability and malignant progression. First, we confirmed that even transient expression of SEPT9_i1 was sufficient to increase aneuploidy in HMECs. We then analyzed SEPT9_i1 by immunoprecipitation and immunofluorescence studies and found that SEPT9_i1 interacts with both α and γ tubulin. SEPT9_i1 expressing cells demonstrated dramatic chromosome segregation defects, centrosome amplification and cytokinesis defects, suggesting two possible molecular mechanisms contributing to the development of genomic instability. This suggests that SEPT9_i1 may promote genomic instability through both cytokinesis and mitotic spindle defects which lead to chromosome missegregation.

Systemic benefit of radiation therapy via abscopal effect.

Evidence of a systemic response related to localized radiation therapy (RT) in cancer management is rare. However, enhancing the immune response via immunotherapy followed by localized RT has shown evidence of tumor shrinkage to non-irradiated metastatic disease thereby inducing an "abscopal effect." Combined induction of the cGAS-STING pathway and activation of IFN-gamma signaling cascade related to RT within an activated immune environment promotes neoantigen presentation and expansion of cytotoxic effector cells enabling enhancement of systemic immune response. A proposed mechanism, case examples, and clinical trial evidence of "abscopal effect" benefit are reviewed. Results support strategic therapeutic testing to enhance "abscopal effect."