|Selected news articles which highlight important policy issues.||
News: Weekly Archives
News for the week of 12-21-2005
The great physician William Osler once observed that “if it were not for the great variability among individuals, medicine might as well be a science and not an art." While medicine will probably never become a push-button profession, where machines and tests replace human judgment, researchers are quantifying how “variability among individuals,” defined by DNA screening, can help guide a doctor’s therapeutic decisions.
The Mayo Clinic this month introduced a genetic test that can tell colon-cancer patients if they are at increased risk of a toxic reaction to one of the primary front-line treatments for the disease.
In a separate study published this week in the Journal of Clinical Oncology, researchers identified a common genetic variant that appears to explain why some women with breast cancer are more likely to relapse while taking the widely used drug tamoxifen.
At the same time, the Food and Drug Administration is weighing action that could pave the way for widespread use of genetic tests that would help tell doctors how big a dose of the blood thinner warfarin to prescribe. Warfarin, taken by more than two million Americans to prevent blood clots, can have serious side effects if patients get too much or too little of the drug. The FDA has also been developing new regulatory guidelines for personalized medicines as it sees growing interest from drug makers looking at ties between genetic tests and how drugs work.
These developments are the latest in a series of steps forward in genetic knowledge that are poised to transform diagnosis and treatment of many diseases. Medicine is beginning to turn from a one-size-fits-all paradigm to a more personalized approach. The tests "allow physicians to think about patients as individuals," says Lawrence Lesko, director of the FDA's office of clinical pharmacology and biotherapeutics. Dr. Lesko oversees the agency's initiative to encourage use of genetic information in drug development.
In particular, genetic tests are likely to reduce adverse drug reactions, which by some estimates cause 100,000 deaths and two million hospital admissions each year in the U.S.
Still, some very important questions remain to be answered. For instance, under what circumstances will public and private insurers pay for the diagnostic tests that are needed to prescribe personalized medicines? Will electronic health records be available that can help patients share their medical histories with providers? Finally, will physicians working in small group or individual practices be comfortable enough with the new technologies to use them effectively?
While these questions are being worked out, the best way for doctors and patients to advance personalized medicine is actually very low-tech: take the time to develop a detailed family history.
FDA approves promising drug for kidney cancer
Typically, clinical trials of cancer drugs test one drug against one type of cancer. Efficacy is usually measured by how quickly (or rather how slowly) the disease progresses, or whether the drug reduces patient mortality. Apparently one of the mid-stage trials that kept this drug alive, and helped lead to FDA approval, used an innovative trial design that tested the drug against many kinds of tumors, allowing researchers to zero in on one type of cancer where the drug was particularly effective.
The U.S. Food and Drug Administration said the agent, Nexavar, is a significant step forward [in kidney cancer therapy]. The current standard treatment for kidney cancer--immune therapy with interferon or interleukin-2--has only modest benefits and can be extremely toxic. The new drug has few side effects, and some patients who started taking it more than two years ago are still doing well, researchers said Tuesday.
Kenneth Vajda, 52, of Naperville was overjoyed when he heard the drug had been approved. He has been taking Nexavar for more than a year. "This is a breeze compared with interferon or interleukin," Vajda said. "I have not missed a day's work on this drug." …
The drug, developed by Bayer with Onyx pharmaceuticals, was originally designed to treat colon cancer, but was ineffective against that disease. It was rescued from oblivion—and ultimately found to work in a different group of patients—thanks to an innovative study design. Doctors enrolled patients with many different tumor types. After 12 weeks, those whose tumors shrank stayed on the drug. Those whose tumors grew were dropped from the trial. And those whose tumors were stable were randomly assigned to receive either Nexavar or a placebo. It soon became apparent that many patients with kidney cancer were responding.
Innovative trial designs is one of the areas that the FDA is expected to advance through its Critical Path project. What most people don’t realize is that clinical trials can miss how different patients respond to drug therapy, because individual responses can be washed out by the overall statistical “noise” of the trial design. Finding better ways to adjust clinical trial designs on the fly, so to speak, can allow researchers to follow up on important leads that might otherwise be missed if the trial was less flexible.
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