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  • Each year cancer kills 8m people worldwide and cost billions
  • 40% of cancer deaths could be prevented by early detection
  • Nearly half of all cancer sufferers are diagnosed late when the tumors have already spread
  • Victims and doctors often miss early warning signs of cancer
  • Traditional tissue biopsies used to diagnose cancer are invasive, slow, costly, and often yield insufficient tissue
  • New blood tests are being devised that simultaneously detect cancer early and inform where the cancer is in the body
  • Such tests - liquid biopsies - are positioned to end the late diagnosis of cancer
  • But before liquid biopsies become common practice they need to overcome a number of significant challenges
  
World’s first blood tests that detect and locate cancer
 
Just as there is a global race among immunotherapists to enhance cancer treatment, so there is a parallel race among bioengineers to speed up and improve the detection of cancer. Such races are important because nearly half of all cancer sufferers are diagnosed late, when their tumors have already metastasized: 30% to 40% of cancer deaths could be prevented by early detection and treatment.
 
Here we describe advances in blood tests - “liquid biopsies” - which can simultaneously detect cancer early, and identify its tissue of origin. We also, describe the growing commercialization of the technology, and some significant hurdles it still has to be overcome.
 
A costly killer disease

Each year cancer kills more than 8m people worldwide, 0.6m in the US and nearly 0.17m in the UK. Survival rates for pancreatic, liver, lung, ovarian, stomach, uterine and oesophageal cancers are particularly low. A large proportion of people do not know they have cancer, and many primary care doctors fail to detect its early warning signs. According to The Journal of Clinical Oncology, a staggering 44% of some types of cancers are misdiagnosed. A significant proportion of people discover that they have cancer only after presenting a different condition at A&E. Each year, the total cost of cancer to the UK’s exchequer is nearly £20bn. In the US, national spending on cancer is expected to reach US$156bn by 2020. And as populations age so some cancer prevalence rates increase, despite substantial endeavours to reduce the burden of the disease.
  
The UK: a stereotypical case

The UK is indicative of what is happening elsewhere in the developed world with regard to cancer diagnosis and treatment. Epidemiological trends suggest that although progress is being made to fight the disease, much work is still required. Death rates for a number of individual cancer types have declined, but rates for a few cancers have increased.

Recently, the UK’s Department of Health invested £450m to improve diagnosis, including giving primary care doctors better access to tests such as CT and MRI scans. But each year there are still some 0.17m cancer deaths in the UK, and 1 in 4 British cancer patients are unlikely to live longer than 6 months after diagnosis because they and their doctors have missed early signs of the disease. For example, in the UK only 23% of lung cancer cases are diagnosed early, as are 32% of cases of non-Hodgkin lymphoma, and 44% of ovarian cancer.

Not only does late detection increase morbidity and mortality, it significantly increases treatment costs. According to the UK’s NHS National Intelligence Network, a case of ovarian cancer detected early costs an average of £5,000 to treat, whereas one detected late at stage three or four costs £15,000. Similarly, a colon cancer patient detected early typically costs £3,000, while one not identified until a later stage would cost some £13,000.

 
Traditional tissue biopsies

Currently, oncologists look to pathologists for assistance in tumor diagnosis. Indeed, oncologists cannot proceed with therapy without a tissue diagnosis, nor are they able to discuss prognosis with the patient. After detecting a tumor through a physical examination or imaging, doctors use traditional tissue biopsies to gather information on the attributes of a patient’s cancer.
 
These pinpoint a cancer’s mutations and malignancy, but solid tissue biopsies are not always straightforward. While some cancers are easily accessed, others are hidden deep inside the body or buried in critical organs. Beyond the physical challenge, sampling from such tumors can be dangerous to patients, and once achieved, they do not always inform on current tumor dynamics. Further, traditional solid tissue biopsies are costly and time consuming to perform; they can yield insufficient tissue to obtain a good understanding of the tumor, and they can be hampered by a patient’s comorbidities, and lack of compliance.

 
Two significant studies
 
Although solid tumor tissue is still the gold standard source for clinical molecular analyses, cancer-derived material circulating in the bloodstream has become an appealing alternative showing potential to overcome some of the challenges of solid tissue biopsies.

Findings of two significant studies of liquid biopsies published in 2017 promise a more effective and patient-friendly method for diagnosing cancer: one in the journal Genome Biology, and the other in the journal Nature Genetics. Both studies are on the cusp of developing the world’s first simple blood test, which can both detect early stage cancer, and identify where in the body the cancer is located.

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The Genome Biology study
 
​The study, reported in Genome Biology, describes findings of a blood test, referred to as the CancerLocator, which has been developed by Jasmine Zhou, Professor of Biological and Computer Sciences and her team at the University of California, Los Angeles (UCLA). The  Locator detected early stage cancer in 80% of breast, lung and liver cases.
 
Zhou and her colleagues devised a computer program that uses genetic data to detect circulating tumor DNA (ctDNA) in blood samples. Once identified, the ctDNA is compared to a database of genetic information from hundreds of people to identify where the tumor is located.  Zhou’s team discovered that tumors, which arise in different parts of the body, have different signatures, which a computer can spot. “The technology is in its infancy and requires further validation, but the potential benefits to patients are huge  . . . . . Non-invasive diagnosis of cancer is important, as it allows the early detection of cancer, and the earlier the cancer is caught, the higher chance a patient has of beating the disease,” says Zhou.
 
The Nature Genetics study

Researchers led by Kun Zhang, Professor of Bioengineering at the University of California, San Diego (UCSD), are responsible for the study published in the journal Nature Genetics. Zhang developed a test that examined ctDNA in blood from cancer patients and, like Zhou, discovered that not only could it detect cancer early, but could also locate where the tumor is growing in the body. When a tumor starts to take over a part of the body, it competes with normal cells for nutrients and space, killing them off in the process. As normal cells die, they release their DNA into the bloodstream; and that DNA can identify the affected tissue.
 
There are many technical differences on how each approach works . . . The work by the UCLA group is a computer program that uses data published previously by other groups, and has reduced the cancer detection error from roughly 60% to 26.5%. In contrast, we developed a new theoretical framework, generated our own data from over 100 patients and healthy people, and our accuracy of locating cancer in an organ is around 90%,” says Zhang, but he adds, “Major medical challenges don’t get solved by one team working alone”.
 
Confluence and advances in computing and biology

The research endeavors of Professors Zhou and Zhang have been made possible by the confluence and advances in computing and molecular biology. Over the past 20 years, there has been a paradigm shift in biology, a substantial increase in computing power, huge advances in artificial intelligence (AI), and the costs of data storage have plummeted. It took 13 years, US$3bn, and help from 7 governments to produce the first map of the human genome, which was completed in 2003. Soon it will be possible to sequence an entire genome in less than an hour for US$100.
 
The end of traditional in vitro diagnostics

Liquid biopsies are a sequencing-based technology used to detect microscopic fragments of DNA in just a few drops of blood, and hold out the potential to diagnose cancers before the onset of symptoms. Roger Kornberg, Professor of Structural Biology at Stanford University, and 2006 Nobel Laureate for Chemistry for his work in understanding how DNA is converted into RNA, “which gives a voice to genetic information that, on its own, is silent,” describes how advances in molecular science are fueling the replacement of traditional in vitro diagnostics with virtually instantaneous, point-of-care diagnostics without resort to complex processes or elaborate and expensive infrastructure. Liquid biopsies, such as those developed by Zhou and Zhang, have the potential to provide clinicians with a rapid and cheap means to detect cancer early, thereby enabling immediate treatment closely tailored to each patient’s disease state.

 
 
FDA approval of liquid biopsy
 
In 2016, the US Food and Drug Administration (FDA) granted Swiss pharmaceutical and biotech firm Roche approval for a liquid biopsy, which can detect gene mutations in the most common type of lung cancer, and thereby predict whether certain types of drugs can help treat it. 

The clinical implementations of such a test are not widespread, and there has been no regulatory approval of liquid biopsies for diagnosing cancer generally. Notwithstanding, ctDNA is now being extensively studied, as it is a non-invasive “real-time” biomarker that can provide diagnostic and prognostic information before and during treatment; and at progression.
 

cfDNA and ctDNA

Cell-free DNA (cfDNA) is a broad term that describes DNA, which is freely circulating in the bloodstream, but does not necessarily originate from a tumor. Circulating tumor DNA (ctDNA) is fragmented DNA, which is derived directly from a tumor or from circulating tumor cells (CTCs).
 
Commercialization of the liquid biopsy race
 
Bill Gates, Jeff Bezos and leading venture capitalists have poured hundreds of millions into the goal of developing liquid biopsies. The US market alone is projected at US$29bn, according to a 2015 report from investment bank Piper Jaffray. Currently, there are about 40 companies in the US analyzing blood for fragments of DNA shed by dying cancer cells. Notwithstanding, only a few companies have successfully marketed liquid biopsies, and these are limited to identifying the best treatments for certain cancers, and to update treatments as the cancer mutates. So far, no one has been successful in diagnosing incipient cancer from a vial of blood drawn from a patient who looks and feels perfectly healthy.
 
Some US companies in the liquid biopsy race

At the 2016 meeting of the American Society of Clinical Oncology (ASCO), a Silicon Valley start-up, Guardant Health, which has raised some US$200m, presented findings from a large study involving over 15,000 participants, which demonstrated the accuracy of its liquid biopsy test, Guardant360, for patients with advanced solid tumors. The study found the same patterns of genomic changes in cfDNA reported by the Guardant360 test as those found in 398 patients with matching tissue samples between 94% and 100% of the time.

The 70-gene test is the first comprehensive, non-invasive genomic cancer-sequencing test to market, and according to the company, about 2,000 physicians worldwide have used it. Guardant expects to continue to develop its technology, and maintain a commercial lead in the cfDNA liquid biopsy space. The next step for Guardant is to go beyond sequencing, which matches patients to targeted oncology drugs to the early detection of cancer itself. 
 
Also in 2016 Gates and Bezos teamed up with San Diego's Illumina, which makes most of the DNA sequencing machines that pick appropriate treatments for cancer patients, to launch another liquid biopsy start-up called Grail. In 2017, Grail raised US$900m to help it develop blood-based diagnostics to enable routine, early detection of cancer. The company aims to refine and validate its liquid biopsy technology by running a number of large-scale clinical studies where it expects to sequence hundreds of thousands of patients. Another Californian-based biotech start-up, Freemome,  raised US$65m to validate its liquid biopsy technology for the early detection of cancer.
 
Takeaways

Despite findings of the two 2017 studies reported in the journals Genome Biology and Nature genetics, FDA approval of Roche’s liquid biopsy, massive increase in investment, and significant commercial biotech activity, there is a gap between reality and aspirations for liquid biopsies. To provide doctors with a reliable, point-of-care means to detect cancer early, liquid biopsies will have to overcome several significant challenges. The major one is assay sensitivity and specificity for analysis of ctDNA and cfDNA. To compete with the gold standard solid tissue biopsy, and to ensure that patients receive early diagnosis and appropriate treatment, a successful liquid biopsy assay will have to demonstrate a high positive predictive value. Concomitantly, good sensitivity and excellent specificity will be required to yield acceptable rates of false positives and false negatives. Notwithstanding, the race among bioengineers to develop a non-invasive “real-time” liquid biopsy to detect cancer early is gaining momentum.
 

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  • Competition is intensifying among scientists to develop and use gene editing and immunotherapy to defeat intractable diseases
  • Chinese scientists were the first to inject people with cells modified by the CRISPR–Cas9 gene-editing technique
  • Several studies have extracted a patient’s own immune cells, modified them using gene-editing techniques, and re-infused them into the patient to seek and destroy cancer cells
  • A new prêt à l'emploi gene editing treatment disables the gene that causes donor immune cells to attack their host
  • The technique harvests immune cells from a donor, modifies and multiplies them so that they may be used quickly, easily and cheaply on different patients
  • Commercial, technical, regulatory and ethical barriers to gene editing differ in different geographies 

Gene editing battles

Gene editing and immunotherapy are developing at a pace. They have been innovative and effective in the fight against melanoma, lung cancer, lymphomas and some leukaemias, and promise much more. Somatic gene therapy changes, fixes and replaces genes at the tissue or cellular levels to treat a patient, and the changes are not passed on to the patient’s offspring. Germ line gene therapy inserts genes into reproductive cells and embryos to correct genetic defects that could be passed on to future generations.  Although there are still many unanswered clinical, commercial and ethical questions surrounding gene therapy, its future is assured and will be shaped by unexpected new market entrants and competition between Chinese and Western scientists, which is gaining momentum.
  
14 February 2017

On the 14th February 2017 an influential US science advisory group formed by the National Academy of Sciences and the National Academy of Medicine gave support to the modification of human embryos to prevent “serious diseases and disabilities” in cases where there are no other “reasonable alternatives”. This is one step closer to making the once unthinkable heritable changes in the human genome. The Report, however, insisted that before humanity intervenes in its own evolution, there should be a wide-ranging public debate, since the technology is associated with a number of unresolved ethical challenges. The French oppose gene editing, the Dutch and the Swedes support it, and a recent Nature editorial suggested that the EU is, “habitually paralysed whenever genetic modification is discussed”. In the meantime, clinical studies, which involve gene-editing are advancing at a pace in China, while the rest of the world appears to be embroiled in intellectual property and ethical debates, and playing catch-up.
 
15 February 2017

On the 15th February 2017, after a long, high-profile, heated and costly intellectual property action, judges at the US Patent and Trademark Office ruled in favor of Professor Feng Zhang and the Broad Institute of MIT and Harvard, over patents issued to them associated with the ownership of the gene-editing technology CRISPR-Cas9: a cheap and easy-to-use, all-purpose gene-editing tool, with huge therapeutic and commercial potential.
 
The proceedings were brought by University College Berkeley who claimed that the CRISPR technology had been invented by Professor Jennifer Doudna of the University, and Professor Emmanuelle Charpentier, now at the Max Planck Institute for Infection Biology in Berlin, and described in a paper they published in the journal Science in 2012. Berkeley argued that after the 2012 publication, an “obvious” development of the technology was to edit eukaryotic cells, which Berkeley claimed is all that Zhang did, and therefore his patents are without merit.

The Broad Institute countered, suggesting that Zhang made a significant inventive leap in applying CRISPR knowledge to edit complex organisms such as human cells, that there was no overlap with the University of California’s research outcomes, and that the patents were therefore deserved. The judges agreed, and ruled that the 10 CRISPR-Cas9 patents awarded to Zhang and the Broad Institute are sufficiently different from patents applied for by Berkeley, so that they can stand. 
 
The scientific community

Interestingly, before the 15th February 2017 ruling, the scientific community had appeared to side with Berkeley. In 2015 Doudna, and Charpentier were awarded US$3m and US$0.5m respectively for the prestigious Breakthrough Prize in life sciences and the Gruber Genetics Prize. In 2017 they were awarded the Japan Prize of US$0.45m for, “extending the boundaries of life sciences”. Doudna and Charpentier have each founded companies to commercially exploit their discovery: respectively Intellia Therapeutic, and CRISPR Therapeutics.
 
16 February 2017

A day after the patent ruling, Doudna said: “The Broad Institute is happy that their patent didn’t get thrown out, but we are pleased that our patent based on earlier work can now proceed to be issued”. According to Doudna, her patents are applicable to all cells, whereas Zhang’s patents are much more narrowly indicated. “They (Zhang and the Broad Institute) will have patents on green tennis balls. We will get patents on all tennis balls,” says Doudna.
 
Gene biology

Gene therapy has evolved from the science of genetics, which is an understanding of how heredity works. According to scientists life begins in a cell that is the basic building block of all multicellular organisms, which are made up of trillions of cells, each performing a specific function. Pairs of chromosomes comprising a single molecule of DNA reside in a cell’s nucleus. These contain the blueprint of life: genes, which determine inherited characteristics. Each gene has millions of sequences organised into segments of the chromosome and DNA. These contain hereditary information, which determine an organism’s growth and characteristics, and genes produce proteins that are responsible for most of the body’s chemical functions and biological reactions.

Roger Kornberg, an American structural biologist who won the 2006 Nobel Prize in Chemistry "for his studies of the molecular basis of eukaryotic transcription", describes the Impact of human genome determination on pharmaceuticals:
 
 
China’s first
 
While American scientists were fighting over intellectual property associated with CRISPR-Cas9, and American national scientific and medical academies were making lukewarm pronouncements about gene editing, Chinese scientists  had edited the genomes of human embryos in an attempt to modify the gene responsible for β-thalassemia and HIV, and are planning further clinical studies. In October 2016, Nature reported that a team of scientists, led by oncologist Lu You, at Ghengdu’s Sichuan University in China established a world first by using CRISPR-Cas9 technology to genetically modify a human patient’s immune cells, and re-infused them into the patient with aggressive lung cancer, with the expectation that the edited cells would seek, attack and destroy the cancer. Lu is recruiting more lung cancer patients to treat in this way, and he is planning further clinical studies that use similar ex vivo CRISPR-Cas9 approaches to treat bladder, kidney and prostate cancers
 
The Parker Institute for Cancer Immunotherapy
 
Conscious of the Chinese scientists’ achievements, Carl June, Professor of Pathology and Laboratory Medicine at the University of Pennsylvania and director of the new Parker Institute for Cancer Immunotherapy, believes America has the scientific infrastructure and support to accelerate gene editing and immunotherapies. Gene editing was first used therapeutically in humans at the University of Pennsylvania in 2014, when scientists modified the CCR5 gene (a co-receptor for HIV entry) on T-cells, which were injected in patients with AIDS to tackle HIV replication. Twelve patients with chronic HIV infection received autologous cells carrying a modified CCR5 gene, and HIV DNA levels were decreased in most patients.
 
Medical science and the music industry

The Parker Institute was founded in 2016 with a US$250m donation from Sean Parker, founder of Napster, an online music site, and former chairman of Facebook. This represents the largest single contribution ever made to the field of immunotherapy. The Institute unites 6 American medical schools and cancer centres with the aim of accelerating cures for cancer through immunotherapy approaches. 

Parker, who is 37, believes that medical research could learn from the music industry, which has been transformed by music sharing services such as Spotify. According to Parker, more scientists sharing intellectual property might transform immunotherapy research. He also suggests that T-cells, which have had significant success as a treatment for leukaemia, are similar to computers because they can be re-programed to become more effective at fighting certain cancers. The studies proposed by June and colleagues focus on removing T-cells, from a patient’s blood, modifying them in a laboratory to express chemeric antigen receptors that will attack cancer cells, and then re-infusing them into the patient to destroy cancer. This approach, however, is expensive, and in very young children it is not always possible to extract enough immune cells for the technique to work.

 
Prêt à l'emploi therapy

Waseem Qasim, Professor of Cell & Gene Therapy at University College London and Consultant in Paediatric immunology at Great Ormond Street Hospital, has overcome some of the challenges raised by June and his research. In 2015 Qasim and his team successfully used a prêt à l'emploi gene editing technique on a very young leukaemia patient. The technique, developed by the Paris-based pharmaceutical company Cellectis, disables the gene that causes donor-immune cells to attack their host. This was a world-first to treat leukaemia with genetically engineered immune cells from another person. Today, the young leukaemia patient is in remission. A second child, treated similarly by Qasim in December 2015, also shows no signs of the leukaemia returning. The cases were reported in 2017 in the journal Science Translational Medicine.
 
Universal cells to treat anyone cost effectively

The principal attraction of the prêt à l'emploi gene editing technique is that it can be used to create batches of cells to treat anyone. Blood is collected from a donor, and then turned into “hundreds” of doses that can then be stored frozen. At a later point in time the modified cells can be taken out of storage, and easily re-infused into different patients to become exemplars of a new generation of “living drugs” that seek and destroy specific cancer cells. The cost to manufacture a batch of prêt à l'emploi cells is estimated to be about US$4,000 compared to some US$50,000 using the more conventional method of altering a patient’s cells and returning them to the same patient. Qasim’s clinical successes raise the possibility of relatively cheap cellular therapy using supplies of universal cells that could be dripped into patients' veins on a moment’s notice.
 
Takeaways
 
CRISPR-Cas9 provides a relatively cheap and easy-to-use means to get an all-purpose gene-editing technology into clinics throughout the world. Clinical studies using the technology have shown a lot of promise especially in blood cancers. These studies are accelerating, and prêt à l'emploi gene editing techniques as an immunotherapy suggest a new and efficacious therapeutic pathway. Notwithstanding the clinical successes, there remain significant clinical, commercial and ethical challenges, but expect these to be approached differently in different parts of the world. And expect these differences to impact on the outcome of the scientific race, which is gaining momentum.
 
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Is immunotherapy a breakthrough in cancer treatment? 

  • Immunotherapy drugs heralded as game changing cancer treatment

  • MD Anderson Professor Allison stripped cancer’s ability to evade attack

  • Nivolumab focuses on the environment around a cancer

  • Immunotherapy drugs are too expensive as sustainable treatments

  • The future is personalized medicine says cancer expert Karol Sikora

A new drug class that neither directly treats nor kills cancer is heralded as a game changer in cancer treatment. 
 

New hope for late stage cancer patients

In March 2015, the American Food and Drug Administration (FDA) awarded an expanded approval for Opdivo (nivolumab), to treat non-small-cell lung cancer, which is the most common type of lung cancer, and means lung cancer patients who have failed other therapies and have no other treatment options, have another shot at containing their tumors. In June 2015, the European Commission approved the same Bristol-Myers Squibb drug in a fast track assessment for previously treated advanced melanoma patients.

Accelerated assessment was given in Europe because Opdivo (nivolumab) qualified as a “Medicinal product of major interest from the point of view of public health, and in particular from the viewpoint of therapeutic innovation.” 

FDA and EU approvals of the drug Opdivo, opens the door for other, next-generation immunotherapies to treat advanced cancers. These are heralded as a new class of game changing drugs. But are they? 
 

The genesis

Because cancer is a result of your body’s own cells growing abnormally, your immune system is held back from recognising cancer as foreign and potentially harmful. This is important because without such checks your immune system would kill you.  

Professor James Allison, director of MD Anderson’s immunotherapy platform, which cultivates, supports and tests new developments of immunology-based drugs and combinations, is credited with ground-breaking research that stripped away cancer’s ability to evade attack by the immune system. Allison’s discoveries led to nivolumab to improve the survival rate of patients with metastatic melanoma, and his insights into the basic biology of immune system T cells is broadly applicable to a variety of cancers. 
 

How it works

These new drugs release the body’s own weapons: killer white blood cells called T cells, and have been likened to taking the brakes off the immune system so that it is able to recognise tumors it wasn't previously recognising, and react to destroy them.

Unlike traditional cancer therapies such as surgery, chemotherapy, radiation or the anti-cancer drugs, immunotherapy does not target the tumor itself. Instead, it focuses on the environment around the cancer, and releases a check on the immune system’s appetite for anything that it does not recognize, so the body’s own defences can recognize tumor cells as targets. Allison says, “This drug doesn’t treat cancer; it doesn’t kill cancer cells so you can’t inject it and expect cancer to melt away immediately because it won’t.” 

However, when nivolumab is combined with tumor-targeted treatments, it lowers the risk of recurrent cancers. It does this by training the body’s T cells to recognize specific features of tumors, just as they do for viruses and bacteria. Thus, the immune system itself is programmed to destroy any returning or remaining cancer.
 

Too costly

Although immunotherapies are generating excitement among cancer clinicians and researchers, clinical studies on melanoma patients show relatively modest prolongations of life, compared with historical norms, at significant costs. For example, the cost of Opdivo (nivolumab) for one patient is about £100,000 per year.

Speaking at the 2015 American Society of Clinical Oncology (ASCO) conference in Chicago, Dr Leonard Saltz from Memorial Sloan Kettering Cancer Center, New York City, suggested that new immunotherapies would cost more than US$1 million per patient per year at the higher dose currently being studied in many different cancer types, and warned, "This is unsustainable.... We must acknowledge that there must be some upper limit to how much we can, as a society, afford to pay to treat each patient with cancer . . As someone who worries about making cancer care available to everyone and minimizing disparities, I have a major problem with this: these drugs cost too much."
      

Takeaway

According to cancer expert Professor Karol Sikora the future of cancer treatment is personalized medicine rather than new immunotherapy products. Personalized cancer care takes into account the individual’s disease, and their personal circumstances. According to Sikora, “The extent to which treatment can be tailored to an individual has been limited by crude descriptions of their disease, and generic treatment options. Advances in genomics and drug responsiveness are leading to more detailed descriptions of a patient’s cancer and better-targeted treatments, which offer significant advantages over blunderbuss chemotherapies. Personalised medicine is the real future for all our patients. Forget the drug hype; this is where the real hope lies”

Here Mike Birrer, Professor of Medicine at the Harvard University Medical School, and Director of the Cancer Center at Massachusetts General Hospital describes personalised medicine:  

         
                (click on the image to play the video)

 

 
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