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US to look for early signs of cancer drug effects (Reuters)
Tue Feb 14th 2006 at 7:11 pm ET
By Lisa Richwine WASHINGTON (Reuters) - Scientists will search for better and earlier signs that a patient is likely to respond to a cancer-fighting drug, or suffer toxic side effects, under a U.S. program announced on Tuesday. Three federal agencies will join together to identify biological indicators, or "biomarkers," that can be analyzed in blood, tissue or other samples, or through imaging scans.Biomarkers already are part of drug development, but health officials said they want to spark much broader applications. If valid biomarkers are identified, drug companies could routinely incorporate those measurements into their clinical trials."It seems like, to many of us, that tremendous opportunities are being wasted right now because trials are being done, and those trials could be used as vehicles to study and qualify biomarkers," said Dr. Janet Woodcock, the Food and Drug Administration's deputy commissioner for operations.The FDA is collaborating with the National Cancer Institute and the Centers for Medicare and Medicaid Services on the effort. Drug companies and private foundations soon may sign on to pool data and funding, Woodcock told reporters.The first project will test if a technology known as FDG-PET scanning, which measures cell metabolism, can predict which patients with non-Hodgkin's lymphoma fare well with drug treatment.That prediction could allow some patients to stop therapy earlier, and avoid harsh side effects from additional chemotherapy, health officials said."If we could predict early response, it would be a huge advantage to patients," said Anna Barker, deputy director of the National Cancer Institute.Drug companies also could use newly discovered biomarkers to get experimental cancer medicines to the market more quickly, without waiting for tests to show if patients actually live longer. Manufacturers are supposed to follow up after approval to make sure a treatment does extend survival, but many of those tests go unfinished.Along with quicker approval, drug companies could see their potential pool of patients shrink, Woodcock said."This is what we hope to see. We hope to see a narrowing of the target population to people who are going to benefit," she said.The drug industry said it welcomed the plan. "This is an excellent beginning toward looking at ways to getting patients the best medicine that works for them," said Mark Grayson, a spokesman for the Pharmaceutical Research and Manufacturers of America.Reader Comments
Wouldn't it be better to experiment in the petri dish rather than the human body?
You give a patient drugs and wait three weeks and then give more drugs and then wait three weeks and then repeat tumor measurements (exam, scans, markers). Using biological markers, which would apparently be found via analysis of blood and tissue samples, or even imaging scans, and could potentially predict which cancer patients will respond to certain therapies, and hopefully reduce the "shotgun" approach to cancer treatment that many oncologists practice today. However, you have the patient getting potentially toxic and ineffective treatment and then you still have to wait weeks until you can then try Plan B.
That's conceptually the same thing drug sensitivity tests are doing. They give drugs and then measure effects on tumors a few days later. That's what assay tests do, only they do it in the laboratory, rather than in the patient. And they can only try one or two treatments at a time. Assay tests can try up to twenty treatments at the same time and see which one works best.
The key to improving drug sensitivity tests is related to the number and types of drugs tested. The more anti-cancer drug types there are in the selective arsenal, the more likely the system is to prove beneficial. In order to acquire sufficient data, tumors should be tested with at least two assay endpoints, and most often three, for sensitivity tests in any one patient. On average, up to twenty drugs and combinations at two concentrations in three different assay systems, is an effective way to avoid false-positive or false-negative data. Careful choice of drug doses and administration intervals also improves outcomes.
Every cancer patient should have his/her own unique chemotherapy trial based on consultation of pathogenic profiles and drug sensitivity testing data. Research and application of drug sensitivity assays are being encouraged by growing patient demands, scientific advances and medical ethics. Drug sensitivity tests are not a luxury but an absolute necessity, and a powerful strategy that cannot be overlooked.