On the other hand, the credibility of personalized medicine should rise as a result of the Mayo Clinic’s interest in evaluating the benefits of applying genetic testing to the prescription of blood-thinner Warfarin. Custom-tailoring that treatment alone to patients’ genetic profiles would enhance patient care and eliminate perhaps as much as a billion dollars a year in healthcare costs.

Genetic testing relies on the identification of disease-contributing genes, and that is on a roll too: Some 150 mutations in 120 genes have been discovered that appear to spur cancer growth, increasing by nearly one-third the number of discovered “cancer genes”; and a specific gene has been identified that contributes to autism. It represents an important step toward the development of effective treatment or cure for the disorder.

Such steps are already being taken in cancer, the latest being a drug combination that targets multiple genes and could dramatically reduce the growth and metastasis of breast tumors.

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A way to determine the results of the firing of individual neurons, involving genetic re-engineering of the neurons, is undergoing animal tests. It could lead to understanding of the precise neural correlates of various disorders, and potentially to precisely targeted treatment of the disorders.

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More than 1,000 genetic tests are available clinically, “hundreds” more are available to researchers, and a few are starting to be marketed direct to consumers, writes Denise Caruso, executive director of the Hybrid Vigor Institute, in an article in the New York Times . In light of uncertainty over the roles of specific genes versus the role of interactions among multiple genes, are the tests as valid and reliable as claimed?, she asks.

The question goes unanswered because there is “no independent review or government oversight of [their] validity.” The US Food and Drug Administration made a start by holding discussions earlier this year on draft guidelines for in-vitro diagnostic multivariate index assays, but “angry” diagnostics manufacturers have denounced the guidelines as confusing, untenable, a “disincentive to innovation,” and possibly even illegal. They rather want such assays to be regulated by the Centers for Medicare and Medicaid Services’ existing regulations known as Clinical Laboratory Improvement Amendments – which say that tests developed by individual labs do not require regulatory review. In other words, the industry wants to be unregulated.

An FDA official counters that multivariate index assays “are based on algorithms that don’t permit even a well-trained physician to really understand whether or not the results are accurate and meaningful or not,” therefore “we think there needs to be somebody looking at the testing that was done to create those algorithms,” and “No one else is doing that, and if we don’t do it, no one else is going to.”

Caruso believes that “No one can blame diagnostics makers for wanting the freedom to develop a new and obviously important market, and as a society we should find every way possible to support their investment in expanding their knowledge and developing these new and powerful technologies. But genetic tests lead people to make life-changing decisions: To undergo surgery, or not. To take, or not take, a drug with potentially significant side effects or benefits. To bear a child or terminate a pregnancy. It is difficult to see either the economic benefit or the ethical wisdom of allowing genetic testing to move forward without even the most basic protections for patients and physicians who will rely on them.”

WSJ on Personalized Medicine

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The Mayo Clinic is collaborating with pharmacy benefits manager Medco in a study to determine whether genetic testing can avoid complications from warfarin use. Drugs such as Warfarin can be dangerous, so delivering the right dose of the right drug to the right patient at the right time is important. Genetic and other molecular tests are beginning to enable drug regimens and other treatments to be custom-tailored to the individual. The movement is known as “personalized medicine.”

One expert told the Wall Street Journal ’s Dinah Wisenberg Brin that personalized medicine is “an explosion about to happen” and “will indeed dominate medicine” in five to no more than 10 years from now.

Its major benefits will be to reduce or eliminate treatment side effects, save patients from taking unneeded drugs, and apply the optimum therapy – one that fits the patient’s genetic profile. It could reduce by “billions of dollars” the money now spent treating life-threatening side effects, on drugs that don’t help the individual, and on treating disease that is preventable in individuals if they are found to be genetically susceptible to it. The use of genetic testing to personalize dosages of warfarin alone could reduce US healthcare spending by US$1.1 billion a year, according to a study by the American Enterprise Institute and the Brookings Institution. It could avoid 85,000 serious bleeding episodes and 17,000 strokes annually in the US.

But it also means that the pharmaceutical industry must change its “blockbuster drug” business model in favor of drugs for smaller populations. It implies a focused consideration of insurance coverage and regulatory standards for new diagnostic tests and therapies.

Medco and Mayo will evaluate the potential of genetic testing on new users of warfarin. The Harvard Medical School-Partners Healthcare Center for Genetics and Genomics is recruiting 500 new warfarin users for a similar study.

More Cancer Genes Uncovered

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Other source : Advisory Board Daily Briefing (subscription service), March 9, 2007, citing Nature , Science Daily , and the Boston Globe .

In what has been described as the “broadest survey yet of the human genome in cancer” British researchers have identified approximately 150 mutations in 120 genes that appear to spur cancer growth. This increases by nearly one-third the number of cancer genes drug developers can use to explore new treatment avenues.

Although it further complicates an already complex picture, the researchers say the study “bodes well for the future of cancer medicine” because it will help researchers develop targeted, gene-based therapies.

Autism Gene

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With the help of gene chips, a massive, multinational, 5-year research effort called the Autism Genome Project has uncovered a specific gene for autism. The gene, neurexin 1, belongs to a family of genes that help nerve cells communicate and are now thought to play a critical role in autism spectrum disorders.

While the discovery is a major step toward eventual development of better treatment and ultimately a cure for autism, a researchers cautioned: “There will almost certainly be an interaction between several genes so this one discovery doesn’t provide a complete answer and may not lead straight to a genetic test but it could be a key step in development for effective treatments as it provides a target for drug development.”

Closer to Metastasis Prevention

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Memorial Sloan-Kettering Cancer Center researchers have shown in mice that simultaneously — as opposed to serially — switching off four identified genes dramatically reduces the ability of breast tumors to metastasize. The four genes produce proteins which combine to enable cancer cells to escape into the bloodstream and get into the lungs. Switching off each gene one by one in human cancer cells implanted in the mice had a small effect on cancer growth and metastasis, but turning off all four at once almost eliminated tumor growth, spread, and angiogenesis.

Cetuximab and celecoxib — drugs known to inhibit two of the proteins produced by the genes — were also shown to reduce the growth and spread of the breast tumors in mice if used in combination. Discussions are underway for clinical trials in humans.

The researchers are also identifying genes that promote metastasis to other sites in the body, such as brain and bone, and investigating whether the same or similar genes are involved in cancer spread in other cancer types, such as colon cancer.

Lightening Depression

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Researchers at Stanford Medical have developed a prototype light-based method for studying, and ultimately for treating, depression and possibly other neurological disorders, with greater effectiveness and fewer side effects than current approaches such as electrical stimulation or drugs.

The method involves genetically engineering neurons to produce a protein which, when exposed to light, triggers electrical activity within that neuron. This in turn triggers activity in neighboring neurons. Researchers can then watch what happens to or in the body as a result of that activation.

Insect and animal experiments involving this method are under way in more than 100 research labs, but its use in humans was described by the lead researcher as “a long way off.”