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LIVE: Lectures by The 2017 Award Recipients of Warren Alpert Foundation Prize in Cancer Immunology, October 5, 2017, HMS, 77 Louis Paster, Boston

Posted in Cancer and Current Therapeutics, CANCER BIOLOGY & Innovations in Cancer Therapy, CAR-T, Conference Coverage with Social Media, Immune Engineering, Immune Modulatory, Immuno-Oncology & Genomics, Immunodiagnostics, Immunology, Immunotherapy, NK Cell-Based Cancer Immunotherapy, Scientist: Career considerations, Warren Alpert Foundation Prize Recipients, tagged , , , on September 8, 2017| Leave a Comment »

Lectures by The 2017 Award Recipients of Warren Alpert Foundation Prize in Cancer Immunology, October 5, 2017, HMS, 77 Louis Paster, Boston

Reporter: Aviva Lev-Ari, PhD, RN

Article ID #242: LIVE: Lectures by The 2017 Award Recipients of Warren Alpert Foundation Prize in Cancer Immunology, October 5, 2017, HMS, 77 Louis Paster, Boston. Published on 9/8/2017

WordCloud Image Produced by Adam Tubman

Top, from left: James Allison and Lieping Chen. Bottom, from left: Gordon Freeman, Tasuku Honjo (NOT ATTENDED), Arlene Sharpe.

Aviva Lev-Ari, PhD, RN was in attendance and covered this event LIVE

 Leaders in Pharmaceutical Business Intelligence (LPBI) Group

The 2017 Warren Alpert Foundation Prize has been awarded to five scientists for transformative discoveries in the field of cancer immunology.

Collectively, their work has elucidated foundational mechanisms in cancer’s ability to evade immune recognition and, in doing so, has profoundly altered the understanding of disease development and treatment. Their discoveries have led to the development of effective immune therapies for several types of cancer.

The 2017 award recipients are:

  • James Allison, professor of immunology and chair of the Department of Immunology, The University of Texas MD Anderson Cancer Center – Immune checkpoint blockage in Cancer Therapy strictly Genomics based drug
  1. 2017 FDA approved a genomics based drug
  2. and co-stimulatory signals
  3. CTLA-4 blockade, CD28, AntiCTLA-4 induces regression of Transplantable Murine tumor
  4. enhance tumor-specific immune response
  5. Fully antibody human immune response in 10,000 patients – FDA approved 2011
  6. Metastatic melanoma – 3 years survival, programmed tumor death, PD-1, MHC-A1
  7. Ipi/Nivo vs. Ipi – combination – 60% survival vs Ipi alone
  8. Anti CTA4 vs Anti-PD-1
  9. responsive T cell population – MC38 TILs
  10. MC38 Infiltrating T cell populations: T-reg, CD4, Effector, CD8, NKT/gamma-delta
  11. Checkpoint blockage modulates infiltrating T cell population frequencies
  12. T reg correlated with Tumor growth
  13. Combination therapy lead to CURE survival at 80% rate vs CTAL-4 40% positive outcome

Not Attended — Tasuku Honjo, professor of immunology and genomic medicine, Kyoto University – Immune regulation of Cancer Therapy by PD-1 Blockade

 

  • Lieping Chen, United Technologies Corporation Professor in Cancer Research and Professor of immunobiology, of dermatology and of medicine, Yale University – Adoptive Resistance: Molecular Pathway t Cancer Therapy – focus on solid tumors
  1. Enhancement – Enhance normal immune system – Co-stimulation/Co-inhibition Treg, and Cytokines, adoptive cell therapy, Lymphoid organs stores
  2. Normalization – to correct defective immune system – normalizing tumor immunity, diverse tumor escape mechanisms
  3. Anti-PD therapy: regression of large solid tumors: normalizing tumor immunity targeting tumor microenvironment: Heterogeneity, functional modulation, cellular and molecular components – classification by LACK of inflamation, adaptive resistance, other inhibitory pathways, intrinsic induction
  4. avoid autoimmune toxicity,
  5. Resetting immune response (melanoma)
  6. Understad Resistance: Target missing resistance or Adaptive resistance Type II= acquired immunity
  • Gordon Freeman, professor of medicine, Dana-Farber Cancer Institute, Harvard Medical School – PD-L1/PD-1 Cancer Immunotherapy
  1. B7 antibody
  2. block pathway – checkpoint blockage, Expand the T cells after recognition of the disease. T cell receptor signal, activation, co -stimulatory: B71 molecule, B72 – survival signals and cytokine production,.Increased T cell proliferation,
  3. PDL-1 is a ligand of PD 1. How T cell die? genes – PD1 Gene was highly expressed,
  4. Interferon gamma upregulate PD-L1 expression
  5. Feedback loop Tumor – stimulating immune response, interferon turn off PD1
  6. PD-L1 and PD-L2 Expression: Interferom
  7. Trancefuctor MHC, B7-2
  8. PD-L! sisgnat inhibit T-cell activation: turn off Proliferation and cytokine production — Decreasing the immune response
  9. T cell DNA Content: No S-phase devided cell
  10. PD-L1 engagement of PD-1 results in activation : Pd-1 Pathway inhibits T Cell Actiivation – lyposite motility,
  11. Pd-L2 is a second ligand for PD-1 and inhibits T cell activation
  12. PDl-1 expression: BR CA, Ovarian, Colonol-rectal, tymus, endothelial
  13. Blockage of the Pathway – Immune response enhanced
  14. Dendritic cells express PD-L1, PD-L2 and combination of Two, Combination was best of all by increase of cytokine production, increasing the immune response.
  15. PD-L1 blockade enhanced the immune response , increase killing and increased production of cytokines,
  16. anti-tumor efficacy of anti-PD-1/Pd-L1
  17. Pancreatic and colono-rector — PD-L, PDL1, PDL2 — does not owrkd.
  18. In menaloma: PD-1 works better than CYLA-4
  19. Comparison of Targeted Therapy: BRAF TKI vs Chemo high % but short term
  20. Immunotherapy – applies several mechanism: pre-existing anti-therapy
  21. Immune desert: PD=L does not work for them
  22. COMBINATION THERAPY: BLOCK TUMOR INVASION THEN STIMULATE IMMUNE RESPONSE — IT WILL WORK
  23. PD blockage + nutrients and probiotic
  24. Tumor Genome Therapy
  25. Tumore Immuno-evasion Score
  26. Antigens for immune response – choose the ones
  27. 20PD-1 or PD-L1 drugs in development
  28. WHO WILL THE DRUG WORK FOR?

 

  • Arlene Sharpe, the George Fabyan Professor of Comparative Pathology, Harvard Medical School; senior scientist, department of pathology, Brigham and Women’s Hospital – Multi-faceted Functionsof the PD-1 Pathway
  1. function of the pathway: control T cell activation and function of maintain immune tolerance
  2. protect tissues from damage by immune response
  3. T cell dysfunction during cancer anf viral infection
  4. protection from autoimmunity, inflammation,
  5. Mechanism by which PD-1 pathway inhibits anti-tumor immunity
  6. regulation of memoryT cell responce of PD-1
  7. PD-1 signaling inhibit anti-tumor immunity
  8. Compare: Mice lacking CD8-Cre- (0/5) cleared vs PD-1-/-5/5 – PD-1 DELETION: PARTIAL AND TIMED: DELETION OF PD-1 ON HALF OG TILS STARTING AT DAY 7 POSTTUMOR IMPLANTATION OF BOTH PD-1 AND PD-1 TILS: – Tamoxifen days 7-11
  9. Transcription profile: analysis of CD8+ TILs reveal altered metabolism: Fatty Acid Metabolism vs Oxidative Phosphorylation
  10. DOes metabolic shift: WIld type mouth vs PD-1-/_ P14: analyze Tumor cell killingPD-1-/- enhanced FAO increases CD8+ T cell tocicity
  11. Summary: T cell memory development and PD-1: T effectors vs T cell memory: Primary vs Secondary infection: In the absent of PD-1, CD8+ T cels show increase expansion of T cells
  12. INFLUENZA INFECTION: PRIMARY more virus in lung in PD-1 is lacking
  13. Acute infection: PD-1 controls memory T cell differentiation vs PD-1 increase expansion during effector phase BUT impaired persistence during memory phase: impaired cytokine production post re-challenge
  14. PD-1 immunotherapy work for patients with tumor: Recall Response and Primary response
  15. TIL density Primary vs Long term survivor – 5 days post tumor implantation – rechallenged long term survival
  16. Hot tumor vs Cold tumor – Deletion of PD-1 impairs T memory cell development

Opening Remarks: George Q. Daley, MD, PhD, DEAN, HMS

  • Scientific collaboration check point – avoid the body attacking itself, sabotaging the immune system
  • 1987 – Vaccine for HepB
  • Eight of the awardees got the Nobel Prize

 

Moderated by Joan Brugge, PhD, HMS, Prof. of Cell Biology

  • Evolution of concepts of Immunotherapy: William Coley’s Toxin streptoccocus skin infection.
  • 20th century: Immuno-surveilence, Immune response – field was dead in 1978 replaced by Immunotherapy
  • Rosenberg at NIH, high dose of costimulatory molecule prevented tumor reappearanceantbody induce tumor immunity–>> immune theraphy by check point receptor blockade – incidence of tumor in immune compromised mice – transfer T cell
  • T cell defficient, not completely defficient, self recognition of tumor,
  • suppress immmune – immune evasion
  • Michael Atkins, MD, Detupy Director, Georgetown-Lombardi, Comprehensive Cancer Center Clinical applications of Checkpoint inhibitors: Progress and Promise
  1. Overwhelm the Immune system, hide, subvert, Shield, defend-deactivating tumor trgeting T cells that ATTACK the immune system
  2. Immune system to TREAT the cancer
  3. Monotherapy – anti PD1/PD-L1: Antagonist activity
  4. Evading immune response: prostate, colcn
  5. MMR deficiency
  6. Nivolumab in relaped/Refractory HODGKIN LYMPHOMAS – over expression of PD-L1 and PDL2in Lymphomas
  7. 18 month survival better with Duv in Lung cancer stage 3 – anti PD-1- adjuvant therapy with broad effectiveness
  8. Biomarkers for pD-L1 Blockage
  9. ORR higher in PD-L1
  10. Improve Biomarkers: Clonality of T cells in Tumors
  11. T-effector Myeloid Inflammation Low – vs Hogh:
  12. Biomarker Model: Neoantigen burden vs Gene expression vs CD8+
  13. Tissue DIagnostic Labs: Tumor microenveironmenr
  14. Microbiome
  15. Combination: Nivo vs Nivo+Ipi is superior: DETERMINE WHEN TO STOP TREATMENT
  16. 15/16 stopped treatment – Treatment FREE SURVIVAL
  17. Sequencing with Standard Therapies
  18. Brain metastasis – Immune Oncology Therapy – crosses the BBB
  19. Less Toxic regimen, better toxicity management,
  20. Use Immuno therapy TFS
  21. combination – survival must be justified
  22. Goal: to make Cancer a curable disease vs cancer becoming a CHronic disease

Closing Remarks: George Q. Daley, MD, PhD, DEAN, HMS

The honorees will share a $500,000 prize and will be recognized at a day-long symposium on Oct. 5 at Harvard Medical School.

The Warren Alpert Foundation, in association with Harvard Medical School, honors trailblazing scientists whose work has led to the understanding, prevention, treatment or cure of human disease. The award recognizes seminal discoveries that hold the promise to change our understanding of disease or our ability to treat it.

“The discoveries honored by the Warren Alpert Foundation over the years are remarkable in their scope and potential,” said George Q. Daley, dean of Harvard Medical School. “The work of this year’s recipients is nothing short of breathtaking in its profound impact on medicine. These discoveries have reshaped our understanding of the body’s response to cancer and propelled our ability to treat several forms of this recalcitrant disease.”

The Warren Alpert Foundation Prize is given internationally. To date, the foundation has awarded nearly $4 million to 59 scientists. Since the award’s inception, eight honorees have also received a Nobel Prize.

“We commend these five scientists. Allison, Chen, Freeman, Honjoand Sharpe are indisputable standouts in the field of cancer immunology,” said Bevin Kaplan, director of the Warren Alpert Foundation. “Collectively, they are helping to turn the tide in the global fight against cancer. We couldn’t honor more worthy recipients for the Warren Alpert Foundation Prize.”

The 2017 award: Unraveling the mysterious interplay between cancer and immunity

Understanding how tumor cells sabotage the body’s immune defenses stems from the collective work of many scientists over many years and across multiple institutions.

Each of the five honorees identified key pieces of the puzzle.

The notion that cancer and immunity are closely connected and that a person’s immune defenses can be turned against cancer is at least a century old. However, the definitive proof and demonstration of the steps in this process were outlined through findings made by the five 2017 Warren Alpert prize recipients.

Under normal conditions, so-called checkpoint inhibitor molecules rein in the immune system to ensure that it does not attack the body’s own cells, tissues and organs. Building on each other’s work, the five award recipients demonstrated how this normal self-defense mechanism can be hijacked by tumors as a way to evade immune surveillance and dodge an attack. Subverting this mechanism allows cancer cells to survive and thrive.

A foundational discovery made in the 1980s elucidated the role of a molecule on the surface of T cells, the body’s elite assassins trained to seek, spot and destroy invaders.

A protein called CTLA-4 emerged as a key regulator of T cell behavior—one that signals to T cells the need to retreat from an attack. Experiments in mice lacking CTLA-4 and use of CTLA-4 antibodies demonstrated that absence of CTLA-4 or blocking its activity could lead to T cell activation and tumor destruction.

Subsequent work identified a different protein on the surface of T cells—PD-1—as another key regulator of T cell response. Mice lacking this protein developed an autoimmune disease as a result of aberrant T cell activity and over-inflammation.

Later on, scientists identified a molecule, B7-H1, subsequently renamed PD-L1, which binds to PD-1, clicking like a key in a lock. This was followed by the discovery of a second partner for PD-1—the molecule PD-L2—which also appeared to tame T-cell activity by binding to PD-1.

The identification of these molecules led to a set of studies showing that their presence on human and mouse tumors rendered the tumors resistant to immune eradication.

A series of experiments further elucidated just how tumors exploit the interaction between PD-1 and PD-L1 to survive. Specifically, some tumor cells appeared to express PD-L1, essentially “wrapping” themselves in it to avoid immune recognition and destruction.

Additional work demonstrated that using antibodies to block this interaction disarmed the tumors, rendering them vulnerable to immune destruction.

Collectively, the five scientists’ findings laid the foundation for antibody-based therapies that modulate the function of these molecules as a way to unleash the immune system against cancer cells.

Antibody therapy that targets CTLA-4 is currently approved by the FDA for the treatment of melanoma. PD-1/PD-L1 inhibitors have already shown efficacy in a broad range of cancers and have been approved by the FDA for the treatment of melanoma; kidney; lung; head and neck cancer; bladder cancer; some forms of colorectal cancer; Hodgkin lymphoma and Merkel cell carcinoma.

In their own words

“I am humbled to be included among the illustrious scientists who have been honored by the Warren Alpert Foundation for their contributions to the treatment and cure of human disease in its 30+ year history.  It is also recognition of the many investigators who have labored for decades to realize the promise of the immune system in treating cancer.”
        -James Allison

“The award is a great honor and a wonderful recognition of our work.”
         –Lieping Chen


“I am thrilled to have made a difference in the lives of cancer patients and to be recognized by fellow scientists for my part in the discovery of the PD-1/PD-L1 and PD-L2 pathway and its role in tumor immune evasion.  I am deeply honored to be a recipient of the Alpert Award and to be recognized for my part in the work that has led to effective cancer immunotherapy. The success of immunotherapy has unleashed the energies of a multitude of scientists to further advance this novel strategy.”
                                        -Gordon Freeman

“I am extremely honored to receive the Warren Alpert Foundation Prize. I am very happy that our discovery of PD-1 in 1992 and subsequent 10-year basic research on PD-1 led to its clinical application as a novel cancer immunotherapy. I hope this development will encourage many scientists working in the basic biomedical field.”
-Tasuku Honjo

“I am truly honored to be a recipient of the Alpert Award. It is especially meaningful to be recognized by my colleagues for discoveries that helped define the biology of the CTLA-4 and PD-1 pathways. The clinical translation of our fundamental understanding of these pathways illustrates the value of basic science research, and I hope this inspires other scientists.”
-Arlene Sharpe

Previous winners

Last year’s award went to five scientists who were instrumental in the discovery and development of the CRISPR bacterial defense mechanism as a tool for gene editing. They were RodolpheBarrangou of North Carolina State University, Philippe Horvath of DuPont in Dangé-Saint-Romain, France, Jennifer Doudna of the University of California, Berkeley, Emmanuelle Charpentier of the Max Planck Institute for Infection Biology in Berlin and Umeå University in Sweden, and Virginijus Siksnys of the Institute of Biotechnology at Vilnius University in Lithuania.

Other past recipients include:

  • Tu Youyou of the China Academy of Chinese Medical Science, who went on to receive the 2015 Nobel Prize in Physiology or Medicine with two others, and Ruth and Victor Nussenzweig, of NYU Langone Medical Center, for their pioneering discoveries in chemistry and parasitology of malaria and the translation of their work into the development of drug therapies and an anti-malarial vaccine.
  • Oleh Hornykiewicz of the Medical University of Vienna and the University of Toronto; Roger Nicoll of the University of California, San Francisco; and Solomon Snyder of the Johns Hopkins University School of Medicine for research into neurotransmission and neurodegeneration.
  • David Botstein of Princeton University and Ronald Davis and David Hogness of Stanford University School of Medicine for contributions to the concepts and methods of creating a human genetic map.
  • Alain Carpentier of Hôpital Européen Georges-Pompidou in Paris and Robert Langer of MIT for innovations in bioengineering.
  • Harald zur Hausen and Lutz Gissmann of the German Cancer Research Center in Heidelberg for work on the human papillomavirus (HPV) and cancer of the cervix. Zur Hausenand others were honored with the Nobel Prize in Physiology or Medicine in 2008.

The Warren Alpert Foundation

Each year the Warren Alpert Foundation receives between 30 and 50 nominations from scientific leaders worldwide. Prize recipients are selected by the foundation’s scientific advisory board, which is composed of distinguished biomedical scientists and chaired by the dean of Harvard Medical School.

Warren Alpert (1920-2007), a native of Chelsea, Mass., established the prize in 1987 after reading about the development of a vaccine for hepatitis B. Alpert decided on the spot that he would like to reward such breakthroughs, so he picked up the phone and told the vaccine’s creator, Kenneth Murray of the University of Edinburgh, that he had won a prize. Alpert then set about creating the foundation.

To award subsequent prizes, Alpert asked Daniel Tosteson (1925-2009), then dean of Harvard Medical School, to convene a panel of experts to identify scientists from around the world whose research has had a direct impact on the treatment of disease.

SOURCE

https://hms.harvard.edu/news/warren-alpert-foundation-honors-pioneers-cancer-immunology

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Koch Institute Immune Engineering Symposium on October 16 & 17, 2017, Kresge, MIT

Posted in Cancer and Current Therapeutics, CANCER BIOLOGY & Innovations in Cancer Therapy, CAR-T, Cell Biology, Cell Biology, Signaling & Cell Circuits, Conference Coverage with Social Media, Genome Biology, Immune Engineering, Immuno-Oncology & Genomics, Immunodiagnostics, Immunotherapy, mRNA platform in Drug DIscovery, NK Cell-Based Cancer Immunotherapy on September 8, 2017| Leave a Comment »

Koch Institute Immune Engineering Symposium on October 16 & 17, 2017, Kresge, MIT

Reporter: Aviva Lev-Ari, PhD, RN

 

Koch Institute Immune Engineering Symposium on October 16 & 17, 2017.

 

Summary: Biological, chemical, and materials engineers are engaged at the forefront of immunology research. At their disposal is an analytical toolkit honed to solve problems in the petrochemical and materials industries, which share the presence of complex reaction networks, and convective and diffusive molecular transport. Powerful synthetic capabilities have also been crafted: binding proteins can be engineered with effectively arbitrary specificity and affinity, and multifunctional nanoparticles and gels have been designed to interact in highly specific fashions with cells and tissues. Fearless pursuit of knowledge and solutions across disciplinary boundaries characterizes this nascent discipline of immune engineering, synergizing with immunologists and clinicians to put immunotherapy into practice.

SPEAKERS:

Michael Birnbaum – MIT, Koch Institute

Arup Chakraborty – MIT, Insititute for Medical Engineering & Sciences

Jianzhu Chen – MIT, Koch Institute

Jennifer R. Cochran – Stanford University

Jennifer Elisseeff – Johns Hopkins University

K. Christopher Garcia – Stanford University

George Georgiou – University of Texas at Austin

Darrell Irvine – MIT, Koch Institute

Tyler Jacks – MIT, Koch Institute

Doug Lauffenburger – MIT, Biological Engineering and Koch Institute

Wendell Lim – University of California, San Francisco

Harvey Lodish – Whitehead Institute and Koch Institute

Marcela Maus – Massachusetts General Hospital

Garry P. Nolan – Stanford University

Sai Reddy – ETH Zurich

Nicholas Restifo – National Cancer Institute

William Schief – The Scripps Research Institute

Stefani Spranger – MIT, Koch Institute

Susan Napier Thomas – Georgia Institute of Technology

Laura Walker – Adimab, LLC

Jennifer Wargo – MD Anderson Cancer Center

Dane Wittrup – MIT, Koch Institute

Kai Wucherpfennig – Dana-Farber Cancer Institute

Please contact ki-events@mit.edu with any questions.

SOURCE

From: Koch Institute Immune Engineering Symposium <ki-events@mit.edu>

Reply-To: <ki-events@mit.edu>

Date: Friday, September 8, 2017 at 9:06 AM

To: Aviva Lev-Ari <AvivaLev-Ari@alum.berkeley.edu>

Subject: Reminder – Register Today

 

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Oncolytic Virotherapy for Pancreatic Cancer: Overcoming Obstacles in Oncolytic Virus Delivery

Posted in Cancer and Current Therapeutics, CANCER BIOLOGY & Innovations in Cancer Therapy, Cancer Vaccines: Targeting Cancer Genes for Immunotherapy, Cell death pathways, Drug Delivery Platform Technology, Immune Engineering, Immuno-Oncology & Genomics, Immunology, Oncolytic virus & OncoViro-Therapy, Pharmacodynamics and Pharmacokinetics, Translational Research, virology, tagged , , , , on July 24, 2016| Leave a Comment »

Oncolytic Virotherapy for Pancreatic Cancer: Overcoming Obstacles in Oncolytic Virus Delivery

Reporter: Aviva Lev-Ari, PhD, RN

 

We covered MGH’s Innovation on Tumor targeted therapy in Pancreatic Cancer in

Pancreatic Cancer Targeted Treatment?

Curator: Larry H. Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2016/05/18/pancreatic-cancer-targeted-treatment/

 

Below, we report on the State of the Science for Overcoming Obstacles in Oncolytic Virus Delivery and provide the source for all the references used

 

ONCOLYTIC VIROTHERAPY FOR PANCREATIC CANCER

Adenovirus

ONYX-015 was the first TOV used in a clinical trial for pancreatic cancer. ONYX-015 was administered intratumourally under endoscopic ultrasound-guidance into patients with locally advanced adenocarcinoma of the pancreas or metastatic disease in phase I/II trials[132]. The treatment was well-tolerated in most patients, however no objective responses were seen with ONYX-015 as a single agent and only 2/21 patients experienced mild responses when combined with gemcitabine[132]. A second adenovirus vector carries a deletion in the E1A gene[133]. E1A normally binds to the retinoblastoma protein, forcing cells to prematurely enter the S phase of the cell cycle. Since most pancreatic cancers harbor a mutation in CDKN2A[134], the E1A protein is unnecessary for entry of the TOV into cancer cells. Furthermore a double-deleted (E1A and E1B19) adenovirus demonstrated increase potency and selectivity in pancreatic cancer models[135,136]. This demonstrates that TOVs can be genetically engineered to increase selectivity and efficacy while maintaining their potency. Adenovirus selectivity has also been improved by engineering tumour-specific promoters such as a human CEA promoter[137] or by substituting the adenovirus serotype 5 fiber knob with the fiber knob from serotype 3[138]. The potency of TOVs can also be improved further by engineering them with therapeutic genes that stimulate the immune system and/or improve direct oncolysis. Adenovirus ZD55-IL-24 expressing IL-24 locally in pancreatic tumours in immune competent mice inhibited tumour growth and induced a stronger T cell response compared to its backbone virus, as measured by IL-6 and IFN-γ levels[139].

HSV

Two oncolytic HSV-1 vectors are currently in clinical trials for the treatment of pancreatic cancer. HF10 is a non-engineered, naturally occurring oncolytic HSV that demonstrated regression in 1/6 of the patients treated[140,141]. OncoVex GM-CSF is a ∆34.5 and ICP47-deleted mutant expressing GM-CSF, whereby the deletions allow for tumour-selective replication and inhibition of protein-kinase R activation, respectively[142]. Phase I/II trials in various solid tumours demonstrated OncoVex GM-CSF to be well-tolerated at high and repeated doses[143,144]. A phase I clinical trial with OncoVex GM-CSF in patients with unresectable pancreatic cancer is underway.

Poxviruses

The most widely studied poxvirus is VV, which is highly immunogenic and produces a strong cytotoxic T cell response[145] and circulating neutralizing antibodies which can be detected decades later[146]. For its crucial role in the eradication of smallpox, much has been learned about its potential role in immunotherapy today. The Lister strain of vaccinia remarkably showed no replication degradation even under the hypoxic conditions of PDAC[147]. A second Lister strain, thymidine kinase-deleted replicating VV armed with IL-10 demonstrated superior and long-lasting antitumour immunity in both a subcutaneous pancreatic cancer model and a Kras-p53 mutant-transgenic pancreatic cancer model after systemic delivery compared to its unarmed backbone virus[148]. Myxoma virus, a rabbit-specific poxvirus combined with gemcitabine resulted in 100% long-term survival in Pan02-engrafted immunocompetent intraperitoneal dissemination models of pancreatic cancer[149]. The only poxvirus to be tested in clinical trials is a non-replicative VV that expresses the pancreatic TAAs CEA and MUC-2[150]. The vaccine also includes a triad of costimulatory molecules, B7.1 (CD80), ICAM-1 (intra-cellular adhesion molecule-1) and LFA-3 (leukocyte function-associated antigen-3) (TRICOM) (PANVAC-VF)[150]. GM-CSF was also used as an adjuvant following each vaccination of PANVAC-VF. Phase I trials demonstrated antigen-specific antitumour responses in 62.5% of patients enrolled and antibody responses against VV was observed in all ten patients, which was associated with an increase in survival (15.1 mo vs 3.9 mo)[48]. A phase III clinical trial for the treatment of metastatic pancreatic cancer after failing treatment with gemcitabine, however, was terminated after failing to reach its primary efficacy endpoint[151].

Other pre-clinical TOVs for pancreatic cancer therapy

Parvovirus, measles virus and reovirus have also demonstrated pre-clinical activity in pancreatic cancer models. Parvoviruses particularly demonstrated enhanced IL-2-activated NK responses against PDAC cells[152,153]. An armed measles virus (MV), MV-purine nucleoside phosphorylase (PNP)-anti-prostate stem cell antigen, that expresses the prodrug convertase PNP, which then activates the prodrug fludarabine, was shown to enhance the oncolytic efficacy of the virus in gemcitabine-resistant PDAC cells[154]. Reovirus is another promising TOV for pancreatic cancer therapy, particularly because its selectivity depends on the cellular activity of Ras, which is constitutively active in pancreatic cancer[155]. Reolysin® (Oncolytics Biotech Inc., Calgary, AB, Canada) a reovirus administered intraportally resulted in decreased metastatic tumour volumes in the liver of immunocompetent animal models[156,157]. A phase II study of Reolysin® in combination with gemcitabine in patients with advanced PDAC has been completed (clinicaltrials.gov: NCT00998322). A two-armed randomized phase II study of carboplatin and paclitaxel plus Reolysin® vs carboplatin and paclitaxel alone in recurrent or metastatic pancreatic cancer is currently being conducted by the United States National Cancer Institute (NCI-8601/OSU-10045).

RATIONALIZING VIRO-IMMUNE-CHECKPOINT COMBINATION THERAPY

A understanding how antitumour immunity is regulated allows us to recognize barriers against effective immunotherapy delivery and furthermore, allow for the development of rational combination therapies aiming targeting these mechanisms[108,158,159]. This approach allows therapies to work synergistically and also has the potential to benefit a broader patient population[108]. Tumours have evolved to avoid immune recognition and/or destruction at every stage in the antitumour response, therefore targeting more than one immune resistance mechanism will enhance antitumour immunity.

An important immunological barrier in cancer immunotherapy is the tolerance towards self-antigens. Tumours downregulate their antigenicity through various mechanisms in response to selective pressure by the immune system, a process called “immunoediting”[37]. Therefore, in order to raise an effective antitumour response, the immunological tolerance must be broken to allow tumour antigen-specific cytotoxic T cell responses[158]. This can be achieved by increasing the tumour load and/or enhance antigen presentation[108]. TOVs can initiate selective infection and replication in the tumour bed, exposing TAA, disrupting the immunotolerance employed by the tumour while re-engaging adaptive immune effector responses[39]. Combining an agent that can cause disruption to the tumour bed i.e., an oncolytic virus, with a novel antitumour immunomodulating agent such as anti-PD-1/PD-L1 antibodies can maximize immune-stimulating and immune-recruiting inflammatory responses[39]. Specifically, TOV lysis induces the release of tumour antigens into the microenvironment, which are then cross-presented to T cells in the draining lymph nodes by APCs[159] (Figure (Figure1).1). This allows T cell infiltration to the tumour bed. Next, T cell dysfunction must be reversed[108,158]. Immune checkpoint inhibitors alleviate immunosuppression, allowing the elimination of the tumour by the adaptive immune system[70]. TOVs in combination with immune checkpoint inhibitors can therefore potentiate and activate the immune system synergistically, ultimately creating a pro-inflammatory environment. Pre-existing TILs are strong prognostic predictors in cancer[106]. This is extremely relevant for tumours with poor immune-cell infiltration, such as pancreatic cancer, which would depend on TOV-infection mediated lymphocyte infiltration for an enhanced response to immune checkpoint blockade. Zamarin et al[160] demonstrated constrained replication of an intratumoural-injected Newcastle disease virus in a B16 melanoma model. Lymphocytic infiltrates, however, were detected in both TOV-injected and non-TOV-injected tumours, and rendered the tumours sensitive to CTLA-4 blockade. The antitumour activity was dependent on CD8+ T cells, NK cells and type I and II IFNs[160]. Ipilimumab with or without talimogene laherparapvec, is in early clinical testing in patients with unresected melanoma (clinicaltrials.org: NCT01740297). Interestingly, an MV engineered to express CTLA-4 or PD-L1 antibodies delayed tumour progression and prolonged median OS in B16 melanoma models[161]. Finally, TOVs have demonstrated a tolerable toxicity profile, whereby flu-like symptoms are the most common adverse events, and in fact, most of the side effects seen so far in the combination regiment are related to the immune checkpoint blockade inhibitor[162]. Dias et al[163] suggested an oncolytic adenovirus expressing CTLA-4 locally might reduce systemic side effects normally induced with anti-CTLA-4 antibodies alone.

OVERCOMING OBSTACLES IN ONCOLYTIC VIRUS DELIVERY

The main issue with virotherapy is systemic delivery for targeting metastatic cancer cells. Intravenous administration is more practical, especially for treatment of a tumour in a hard-to-reach location such as the pancreas, and with the majority of patients presenting with advanced or metastatic disease. However, nonimmune human serum and existing anti-TOV antibodies may neutralize the TOV in the bloodstream. Furthermore, non-specific hepatic and splenic sequestration of the TOV and ineffective extravasation into the tumours are important issues[164]. Currently, studies in pre-clinical models aim to overcome these obstacles. These include chemical modification of viral coat proteins by conjugation of biocompatible polymers e.g. polyethylene glycosylation[165,166], using mesenchymal stem cell carrier systems to deliver the TOV to the tumour bed[167–169], and increasing vessel permeabilization[170,171].

In PDAC, however, the biggest hurdle may not be the host immune system, but the TME. The TME has played a significant role in not only acting as a physical barrier to deliver treatments, but it also in the development of resistance to conventional drugs. The TME remains a problem for successful TOV treatment. The TOV must be able to spread in the hypoxic and densely stromal-rich TME in order to attract enough attention to induce antitumour immunity[172]. Breaching the stromal barrier in PDAC is needed for TOVs to access the cancer cells[173]. Paradoxically, a recent study by Ilkow et al[174] demonstrated that the cross-talk between CAFs and cancer cells actually lead to increased permissibility of TOV-based therapeutics. Tumour cells producing TGF-α reprogrammed CAFs, dampening levels of anti-viral transcripts. This allowed the cells to be more sensitive to VV, vesicular stomatitis virus and maraba MG1 TOVs. The reprogrammed CAFs produced fibroblast growth factor (FGF)-2 which suppressed levels of retinoic acid-inducible gene I and increased the susceptibility of the tumour cells to virus[175]. This study also demonstrated that an FGF2-expressing TOV has improved therapeutic efficacy by sensitizing the tumour cells to virotherapy and is particularly relevant to pancreatic cancers, where CAFs are a major component of the tumour stroma[175]. It is important to note that not only the patient’s existing immune system may impede successful TOV therapy, but that the enhanced antitumour response by combinatory approaches (e.g., the inclusion of immune-checkpoint inhibitors) may also impede successful TOV infection, spread and engagement of the immune system. This stresses the importance of determining strategic combinations, dosing and timing schedules in future studies.

CONCLUSION

The poor prognosis of pancreatic cancer due in part to the limited efficacy of conventional and targeted therapies, appeals for a novel strategy to treat this disease. It has become very clear that the immune system has the greatest potential to selectively destroy tumours, and when it is strategically induced, a durable benefit can be achieved. Past and present studies have defined means for tumour escape from immune surveillance and have developed immunotherapies to counteract these mechanisms. However, with the various escape strategies leading to low immunogenicity and highly immunosuppressive tumour beds, a successful control of tumour growth by immunotherapy does not come without various obstacles and challenges. Future steps include the development of immune-monitoring strategies for the identification of biomarkers, to establishment guidelines to assess clinical end points of immunotherapy and finally to evaluate combination therapeutic strategies to maximize clinical benefit[176]. The ability of TOVs to stimulate inflammation, deliver genes and immunomodulatory agents as well as reduce tumour burden by direct cell lysis, allows them to be important therapeutic vectors for a highly immunosuppressed tumour such as PDAC. Immune checkpoint blockade agents can then reverse T cell anergy and further boost OV-induced responses. As this combinatory approach may exist as a double-edged sword, it is crucial to determine appropriate timing, dosing and sequence schedules of each agent.

SOURCE & REFERENCES

World J Gastroenterol. 2016 Jan 14; 22(2): 748–763.
Published online 2016 Jan 14. doi:  10.3748/wjg.v22.i2.748
PMCID: PMC4716074

Viro-immune therapy: A new strategy for treatment of pancreatic cancer

Andrea Marie Ibrahim and Yao-He Wang
Author information ► Article notes ► Copyright and License information ►
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4716074/ 

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