As many as 25 percent to 50 percent of new cancer treatments tested in Phase III randomized clinical trials are eventually found to be effective, according to researchers who analyzed data from 624 trials involving more than 216,000 patients.

The researchers also found that 30 percent of the trials had statistically significant results. And in 80 percent, new meds were superior to established treatments. The risk-benefit ratio favored new treatments in 41 percent of comparisons, and favored standard treatments in 59 percent. Another finding - breakthrough therapies were discovered in 15 percent of the trials and, in 2 percent of the cases, breakthroughs reduced death rates by more than 50 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 authors wrote in The Archives of Internal Medicine. “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 trials were conducted by cooperative groups funded by the National Cancer Institute. Two of the co-authors received consulting fees and grant support from Sanofi-Aventis, Amgen and Lilly, which, of course, market drugs to treat various cancers.

“In conclusion, society has received a good return on its investment in the cooperative oncology group system,” which funds the trials, the 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.”