Cancer-killing viruses zero in on tumor cells

Doctors have known for nearly a century that when cancer patients catch a virus the infection can help to beat back their tumors. But developing therapies hinged upon this idea has not been easy. Researchers first have to engineer the viruses to discriminately attack only the cancer cells. Then the virus has to actually reach those tumor cells and kill them. Despite these barriers, research has plunged forward, with several viruses in late-stage clinical development (see ‘Recent deal highlights hopes for cancer-killing viruses’).

Clinicians typically inject these so-called ‘oncolytic viruses’ into the tumors themselves using a syringe. But this delivery approach lacks precision. Thus, researchers have long sought cancer-killing viruses that can home in on cancerous cells on their own while leaving healthy tissue intact. (Scientists are similarly trying to develop bacteria that serve the same purpose, as we reported in March.) Now, for the first time, researchers have engineered a virus that, when injected into people’s bloodstreams, preferentially attacks only cancer cells.

“This data set really puts oncolytic virotherapy on the map as a very, very promising experimental approach to the systemic treatment of metastatic cancer,” Stephen Russell, director of the molecular medicine program at the Mayo Clinic in Rochester, Minnesota who was not involved with the research, wrote in an email.

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Bioethics commission condemns Guatamalan syphilis research as unethical

Crossposted from Nature’s news blog

Researchers knowingly violated ethical boundaries when they intentionally infected Guatamalan prisoners, mental health patients, and prostitutes with sexually transmitted diseases in a 1940s research project, a presidential commission concluded yesterday.

When the harrowing experiments came to light (see ‘A shocking discovery’), President Barack Obama charged the President’s Commission for the Study of Bioethical Issues with investigating the matter. After picking through 125,000 pages of historical documents, the committee determined that the experiments were unethical even by the prevailing norms of the era, and that those who conducted the research actively sought to keep experiments out of the public eye.

It was also no accident that the research was performed in Guatemala, argued Amy Gutmann, chairwoman of the commission and president of the University of Pennsylvania. “Some of the people who were involved in this experiment explicitly said, ‘We could not do this in our own country’,” she said. “It was a foreign population that was seen as ethnically, racially, nationally different.”

“The only way you could continue doing this is to think of what you were working on as material as opposed to human subjects,” Gutmann added.

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Essential heart drugs remain badly underused, particularly in poor countries

Over the past two decades, drug therapies have done wonders to improve the survival and quality of life for people living with heart disease and stroke. Antiplatelets, such as aspirin, decrease blood clots; beta blockers, angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) reduce blood pressure; and statins curb ‘bad’ cholesterol levels. Despite these benefits, however, these drugs go underused, particularly in low-income countries, according to a study published yesterday in The Lancet.

“Strong action is needed,” Tony Heagerty, who studies cardiovascular medicine at the UK’s University of Manchester, wrote in an accompanying commentary. “An epidemic of cardiovascular disease is just beginning in many countries that are ill prepared for what is to come.”

The study, led by Salim Yusuf of McMaster University in Hamilton, Ontario, recruited more than 150,000 people from 17 countries who self-reported their medical histories and drug use. Of the 7,500 people who had coronary heart disease or a stroke, only 25% took antiplatelets, 17% took beta blockers, nearly 20% took ACE inhibitors or ARBs, and fewer than 15% took statins. In addition to the new report, Yusuf’s team also presented the findings over the weekend at the European Society of Cardiology Congress in Paris.

The rates of drug use were far lower in poorer countries, the researchers found. For example, someone suffering from heart attack or stroke in India is seven times less likely to receive aspirin and 20 times less likely to be on statins than an average Canadian, the Times of India reports. Other groups with particularly low drug use were women, younger people, rural populations, current smokers and the non-obese.

“Even in well developed health-care systems many patients are not receiving the best secondary prevention treatment,” wrote Heagerty. “The message is clear: the strategy needs a fresh look and reinforcement.”

NEWS FEATURE: Taking tissue engineering to heart — a look at the first US trial of tissue-engineered blood vessels

More than a decade after Japanese scientists implanted the first bioengineered blood vessel into a child with a congenital heart defect, the experimental treatment has finally made its way into clinical testing in the US. Elie Dolgin asks what took so long and what lessons have been learned along the way.

Click the image above for a PDF of the full story from the September 2011 issue of Nature Medicine.

Last week, a team of around a dozen doctors and nurses in Connecticut performed a 12-hour operation to insert a cigar-shaped plastic tube, seeded with bone marrow cells, around the heart of a toddler born with only a single functioning ventricle. The delicate surgery, performed at the Yale-New Haven Hospital, represents the first time that surgeons have implanted a tissue-engineered blood vessel into someone on US soil. It could radically alter the future treatment of this type of congenital heart defect — which affects around 3,000 babies born each year in the US — and could have implications for more common heart procedures down the road.

For the trial investigators, the surgery has been more than a decade in the making. “See the black binders,” says Christopher Breuer, gesturing to a bookshelf in his small, sunlit office. Breuer, a pediatric surgeon at the Yale University School of Medicine who has spearheaded the experimental surgery, stands up and pulls out one of more than a dozen thick binders lining the wall. “All but three of these constitute a single copy of the first application” to the US Food and Drug Administration (FDA) to approve the clinical protocol, submitted in August 2009. “Things moved along very slowly,” he admits. That’s especially true when you consider that the same surgery had already been performed on 25 people, starting ten years earlier, by Toshiharu Shinoka and his colleagues at the Tokyo Women’s Medical University Hospital in Japan.

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Adverse effects from vaccination are rare, but children with weak immune systems need more attention, says IOM report

syringe82511.jpgToday, a committee from the US Institute of Medicine released its report on the adverse effects of vaccines, reviewing data from over 1,000 scientific papers. Many news sources reported on the main findings of the report, which is that vaccines are largely safe, and that the evidence does not support a link to autism or type 1 diabetes. The findings come at a time when parents and patients are more concerned about the adverse effects of vaccines than ever.

“Parents rate the safety of vaccines and drugs as the number one research priority that we have for children’s health,” says Matthew Davis, a pediatrician and professor of health policy at the University of Michigan in Ann Arbor who was not on the committee. “The new report may help families feel like they’re making a more informed decision.”

The report’s goal is to advise the Vaccine Injury Compensation Program, a government service administered by the US Department of Health and Human Services, which doles out payment to people demonstrably injured by vaccines. The IOM’s review out today should help workers in the program decide whether a medical problem is a true side effect of vaccination, increasing the program’s efficiency, says Clay Johnston, an epidemiologist at the University of California, San Francisco who served on the committee. “If there are clear associations between a symptom and a vaccine, you know that you can compensate those people,” he says, adding that the occurrence of such adverse events are rare.

But the report also acknowledged that although the risk from vaccines is small, certain people are more at-risk than others. In particular, immunodeficient individuals are more likely to develop complications resulting from live-virus vaccines. By adulthood, most people know whether they have an immune system problem, and those who do will not receive flu shots. In comparison, infants are less likely to show signs of immune weakness before their first shots, and that’s where the danger lies.

“If you have one of these rare [immunodeficient] conditions, live vaccines can be lethal,” says Jennifer Puck, a pediatric immunologist at the University of California, San Francisco. “It’s one of the important reasons to institute newborn screening for the severe diseases that can be detected these days.”

Some states have already mandated screening for immunodeficiencies in infants. In May 2010, health secretary Kathleen Sebelius added severe combined immunodeficiency (SCID), a genetic disorder causing a highly compromised immune system, to her recommended panel of tests administered at birth. In reaction, five states have picked up the banner — Wisconsin, Massachusetts, California, Louisiana and New York — requiring a test for this immunodeficiency before newborns leave the hospital.

Puck herself found seven cases of SCID in otherwise-healthy infants last year in enough time to cancel their vaccinations and give them a life-saving bone marrow transplant, validating the use of these tests. But more states need to start mandating immune tests in infants, she says. “Hospitals just have to gear up to run one more test on that same sample” taken for the basic battery of newborn tests, she says. “It’s not difficult to do as these five states have shown.”

The report highlights the areas that need more research, including immunodeficiency diagnosis and other risk areas, says Louis Cooper, professor emeritus of pediatrics at Columbia University College of Physicians & Surgeons in New York. “The report is very clear in laying out where there are gaps in our knowledge and can serve as a useful tool for scientists as they design their studies,” he says. “It will help us to shape the resources and the mechanisms and the structure that will allow us to fill in the gaps we know about now.”

Image: via Flickr user Andres Rueda under Creative Commons

Taking a ‘natural’ approach could improve the value of electronic medical records

computerdoctor222.jpgElectronic medical records hold great promise to facilitate efficient healthcare. No longer will nurses squint to decipher doctors’ chicken scratch on paper forms, and patients can have their medical records transferred between healthcare providers with ease. But interpreting all the data in the system can present a challenge.

A simple keyword search in a database pulls up far too many results, including many irrelevant ones. For example, if you searched ‘pneumonia’ in the medical records, you would retrieve the cases of pneumonia you desired — but also every single time pneumonia was mentioned in passing.

“In an ideal world, all clinical data should be structured and coded, mapped with a standard terminology,” says Stéphane Meystre, a biomedical informaticist at the University of Utah Medical School who was not involved with the research. “But clinicians like to tell things their way, so we need a way to extract data from narrative text.”

One solution to help computers decode the context of all the medical terms in a system might be natural language processing, an artificial intelligence tool that goes beyond a basic keyword search, according to a study out today in the Journal of the American Medical Association. This analytical tool incorporates sentence structure “to take into account the context of what you’re trying to say,” says Harvey Murff, associate professor of medicine at Vanderbilt University and lead author.

Murff and his colleagues used natural language processing to search the medical records of nearly 3,000 patients at six Veterans Health Administration medical centers for adverse effects following surgery, including renal failure, sepsis, heart attack and pneumonia. They compared their results to patient reviews done by reading straight from the paper charts— considered the gold standard, he says. Pooling the data from all complications, natural processing language identified 77% of all adverse events found in the paper-based undertaking. By comparison, a traditional keyword search only identified 42% of post-surgical complications.

The unfortunate reality is that the system still cannot decipher mis-entered information. Clinicians sometimes rush the process of entering notes into the computer, leading to typos and misspellings, or use non-standard abbreviations. Additionally, “the meanings [of terms] changes from specialty to specialty, hospital to hospital, even in the same documents,” Meystre says.

Murff says that even though his language analysis tool can help sort through the information in a system, it is not perfect. “It’s unlikely that you’d have a tool like this that would ever be 100% accurate,” says Murff. “After all, it’s people; we take shortcuts.”

Natural language processing is one tool, but it’s likely not the final word.

Image: flickr user southerntabitha via Creative Commons

VIDEO: The war is on to replace warfarin

Earlier this month, the European Medicines Agency approved Boehringer Ingelheim’s blood-thinner drug Pradaxa (dabigatran) as a stroke prevention treatment in people with a cardiac arrhythmia condition known as atrial fibrillation. The clot-prevention agent, which gained US approval last October, is the first replacement to the anticoagulation standby warfarin to be green-lighted for this disease in 50 years — but it’s probably not the last.

Next month, a panel of experts convened by the US Food and Drug Administration will consider whether Bayer and Johnson & Johnson’s Xarelto (rivaroxaban), currently approved in the EU, US and Canada to prevent blood clots in people having hip and knee replacement surgeries, should be used to treat atrial fibrillation. And later this month, Bristol-Myers Squibb and Pfizer will present data at the European Society of Cardiology meeting in Paris showing that their Eliquis (apixaban) — currently also approved in the EU for post-surgery treatment — is better and safer than warfarin for the same indication.

With annual sales of stroke prevention drugs expected to reach $14 billion by 2017, these new medicines could become big earners. Here, Nature Reviews Drug Discovery presents a video outlining the half-century quest to bring these agents to market.

FDA rushes approval of first mutation-specific melanoma drug

The US Food and Drug Administration today approved the first of a new class of skin cancer drugs aimed at a common mutation implicated in driving tumor growth.

The oral targeted therapy, marketed as Zelboraf (vemurafenib) by Genentech of South San Francisco and Daiichi Sankyo of Japan, was given the nod more than two months ahead of schedule to treat metastatic melanoma in people harboring a mutated form of the B-RAF oncogene. Alongside the drug, the FDA also approved Roche Molecular System’s companion diagnostic test for the mutation.

“The new age of cancer therapeutics has been ushered into melanoma with this drug,” says cancer genome researcher Levi Garraway of the Dana-Farber Cancer Institute in Boston. “An age where it’s not solely about where in the body the cancer arose, but the importance of genetics in the tumor holds the decisive seat at the table.”

Around half of all people whose melanoma metastasizes develop a specific point mutation in their B-RAF gene. This mutation ramps up the activity of the encoded protein, stimulating a growth pathway that causes the cancerous cells to multiply unchecked. Zelboraf, which the Wall Street Journal reports will cost around $56,400 for a six-month treatment, works by inhibiting the mutant protein, preventing activation of the signaling cascade.

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Researchers measure bacteria’s heat to diagnose tuberculosis

Mycobacterium_tuberculosis.jpgReports of multidrug resistant tuberculosis in every region of the world have raised red flags over the past few years, but clinicians have a far more basic problem on their hands: diagnosing the disease. The World Health Organization (WHO) reported last year that one-third of tuberculosis infections go undetected or are poorly treated, leading to disease spread and evolution of drug resistance.

The most accurate diagnosis is made by culturing the bacteria that causes the disease, Mycobacterium tuberculosis. However, this process takes around two months — far too long for clinicians to respond quickly in the field. Serological tests that detect anti-tuberculosis antibodies in the blood take less than an hour. But last month, the WHO, in its first-ever explicit ‘negative’ policy recommendation, cautioned against using these tests after researchers showed that they are neither accurate nor cost-effective.

The apparent need for a fast and cheap diagnostic test has pushed researchers to develop novel methods. One such approach was published online today in the Journal of Applied Microbiology. The researchers measured the heat cast off by growing bacteria — a technique known as isothermal microcalorimetry — to diagnose tuberculosis and related infections. Policy makers and doctors have historically ignored this method because the required equipment is too expensive. But this study provides evidence that a low-cost version of the instrumentation can diagnose the disease in less than two weeks.

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Billionaire and activist investor Carl Icahn pulls out of Biogen Idec

icahn.jpgIn August 2007, billionaire Carl Icahn took hold of 2.7 million of Biogen Idec’s shares, making him one of the company’s largest investors. Over the next few years, he grew his ownership in the Weston, Massachusetts-based biotech, holding 8.2 million shares valued at nearly $750 million as recently as June of this year. But yesterday, after four years of attempted control of the company’s direction and management, Icahn disclosed that he has dumped all of his stock in the company, according to the Wall Street Journal.

Ever since he first invested in Biogen Idec, Icahn has tried to wrench control of the drugmaker best known for its drugs for treating multiple sclerosis. He insisted that the board sell Biogen Idec at the end of 2007, and when they failed to find a buyer, Icahn accused them of lying about their effort. In 2009, the board elected two of his four nominated directors at his urging — and two months later, two other board members resigned (although former director Cecil Pickett told Nature that early resignation was “the plan all along”).

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