Many Phase 3 Cancer Drug Trials Yield Effective Medicines
Between a third and a half of these studies bring real clinical improvements, researchers say
MONDAY, March 24, 2008 (HealthDay News) -- From 25 percent to 50 percent of new cancer treatments tested in phase 3 randomized clinical trials are eventually found to be effective, say American researchers who analyzed data from 624 phase 3 trials involving more than 216,000 patients.
The trials were all conducted by U.S. National Cancer Institute-funded cooperative groups since 1955.
Dr. Benjamin Djulbegovic, of the H. Lee Moffitt Cancer Center and Research Institute at the University of South Florida in Tampa, and colleagues found that 30 percent of the trials had statistically significant results.
In 80 percent of those trials, new treatments were found to be superior to established treatments. The risk-benefit ratio favored new treatments in 41 percent of comparisons, and favored standard treatments in 59 percent of comparisons.
"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 study authors wrote. "When done this way, new treatments are, on average, found to be slightly superior to standard treatments, with a five percent relative reduction in the death rate. This, of course, should not be understood as the average effects of new discoveries being equally spread among all patients."
The researchers also found that breakthrough therapies were discovered in 15 percent of the trials and, in two percent of cases, the breakthroughs reduced the death rate by more than 50 percent.
The study was published in the March 24 issue of the journal Archives of Internal Medicine. Two of the study co-authors received consulting fees and grant support from drug makers Sanofi-Aventis, AMGEN, and Eli Lilly and Company.
"In conclusion, society has received a good return on its investment in the cooperative oncology group system," which funds the trials, the study authors wrote. "The public can expect that about 25 percent to 50 percent of new cancer treatments that reach the stage of assessment in clinical trials will prove to be successful. 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."
Cancer is the second leading cause of death in the United States. Over the years, there have been continuous improvements made in survival and other outcomes, in large part due to the introduction of new treatments tested in clinical trials, according to background information in the study.
The U.S. National Cancer Institute has more about cancer clinical trials.