gdpawel
Senior User
Joined: 15 Jan 2005
Posts: 123
Location: Pennsylvania
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 Posted: Tue Jan 10, 2006 1:38 pm Post subject: New Generation Clinical Trials Could Improve Patient Care |
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The Bayesian method is no stranger to the technology of Cell Culture Assay Testing (Chemosensitivity Testing). In fact, it is what gives credit to the accuracy of assay tests. The method has to do with "conditional probability." The probability that event E (an effect) and C (a cause) will both occur is the product of the event C occurring, times the conditional probability of an event E occuring (remember that in elementary statistics?). An example: The chances of being hit by a truck and bleeding to death is the product of the probability of being hit by a truck and the probability of bleeding to death if you get hit by a truck. Well, so what?
The Bayesian method turns this calculation around. That is, it tries to calulate the probability of C, given that E has occurred. Baye's Theorem is useful and reasonably well accepted for some applications such as testing whether the assumptions of probability are valid. For instance, if you flip 100 coins in the air at once, and only get tails 5 times, you have to assume that they aren't "fair" coins. The whole idea of it all, is to get more accuracy out of analysis.
The University of Texas M.D. Anderson Cancer Center is taking a fresh look at how to evaluate new medicines and treatments for cancer. Dr. Donald Berry, Ph.D., professor and chair of the Department of Biostatistics and Applied Mathematics says, "We need to rethink how we design and conduct clinical trials in the United States." He feels that we should turn the "statistical method" used to evaluate new drugs on its head, stating that it limits innovatlion and learning.
For more than 30 years, he has been advocting the adoption of the Bayesian method because it is more in line with how science works. A recent press release from the institution states that he is putting his approach to the test with more than 100 cancer-related phase I and II clincial trials being planned or carried out using the Bayesian approach.
Clinical trials test the efficacy (not the accuracy) of a drug. The efficacy of a drug is to produce a desired effect, which is tumor response. Single arm clinical trials provide the tumor response evidence that is the basis for approving new cancer drugs. The randomized, controlled clinical trial may likely remain the standard for evidence of clinical decision-making in cancer medicine, however, the Bayesian methology can bring some much-needed "accuracy" to the forefront.
Clearly, more effective cancer therapies are desperately needed, and after 30 years of investigation aimed at intensified multi-agent chemotherapy, we should look for other avenues of study. In an era of ever-increasing numbers of partially effective cancer therapeutics, there is an obvious need for more accurate methologies.
http://www.mdanderson.org/departments/newsroom/display.cfm?id=f90987e4-8ebb-4e10-8ed282ec15dd38e9&method=displayfull&pn=00c8a30f-c468-11d4-80fb00508b603a14 |
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