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New cancer drugs successful up to half the time
Apr 02, 08 Clinical Updates Medical Product Safety AlertsApproximately one-fourth to one-half of new cancer treatments that enter late-stage testing are eventually proven successful, research shows.
Dr. Benjamin Djulbegovic from H. Lee Moffitt Cancer Center and Research Institute at the University of South Florida, Tampa, and colleagues assessed how often new treatments for cancer evaluated in phase 3 randomized controlled trials sponsored by the National Cancer Institute from 1956 to 2006 were superior to standard treatments. A total of 624 trials involving 216,451 patients were analyzed.
Overall, 30 percent of the trials had statistically significant results; in 80 percent of those cases, new treatments were superior to established treatments, the investigators found.
The trial investigators, who took into account both risk and benefit, concluded that the experimental treatments were superior in 41 percent of the trials, whereas standard treatments were superior in 59 percent.
“The real effects of new treatments compared with standard treatments in terms of patient outcomes such as survival is best measured by quantitative pooling of data,” the investigators note. Quantitative pooling of the data demonstrated a slight superiority for experimental over standard treatments, with a 5 percent relative reduction in the death rate, they say.
This benefit was not, however, uniform. For example, trial investigators judged that 15 percent of the trials resulted in the discovery of breakthrough interventions and 2 percent of the trials identified experimental interventions that reduced death rates by at least 50 percent.
The fact that a substantial number of trials were inconclusive is a concern. “There were a tremendous proportion of inconclusive studies,” Djulbegovic said. “I think it is expectation bias—the studies accrued more patients than planned, but the investigators anticipated an unrealistically optimistic treatment effect.”
The investigators conclude, based on their research, that “society has received a good return on its investment in the cooperative oncology group system,” which funds the trials.
“The public can expect that about 25 percent to 50 percent of new cancer treatments that reach the stage of assessment in randomized clinical trials will prove to be successful,” they write. “This pattern of successes has become more consistent over time. However, our results also indicate that the absolute number of discoveries might be improved if the proportion of inconclusive trials is reduced.”
SOURCE: Archives of Internal Medicine, March 24, 2008.
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