One in 6 patients in phase 2 cancer trials received treatments that were eventually approved by the US Food and Drug Administration (FDA), a new analysis found. This proportion increased to 1 in 5 when considering National Comprehensive Cancer Network (NCCN) off-label recommendations and decreased to about 1 in 11 for approved regimens considered to have a substantial clinical benefit.
"By entering a phase 2 trial, a patient has a 1 in 6 chance of receiving a treatment that will later be approved for their condition," the authors wrote. "The proportions described here, when juxtaposed with those estimated previously for phase 1 trials, suggest a striking improvement for a patient's therapeutic prospects. This suggests that phase 1 trials do a good job at protecting patients downstream from unsafe and ineffective cancer treatments."
In an editorial accompanying the study, Howard S. Hochster, MD, of the Rutgers Cancer Institute in New Brunswick, New Jersey, suggested that the 16.2% therapeutic proportion reported may be understated. For instance, "If using the criterion of drugs that were FDA approved in any indication and dose, the proportion of patient benefit in these trials rises to 38%, with a 51% benefit rate considering inclusion in NCCN guidelines," he wrote.
This study, led by Charlotte Ouimet, MSc, Department of Equity, Ethics and Policy, McGill University School of Population and Global Health, Montréal, Québec, Canada, was published online in JNCI: Journal of the National Cancer Institute.
The longitudinal design of this study required using a historical cohort of phase 2 clinical trials, which may not reflect current drug development patterns. This study was underpowered to determine trial characteristics that predicted higher therapeutic proportions. Furthermore, the exclusion of cytotoxic drugs from the analysis resulted in a somewhat restricted view of overall drug development.
This study was supported by the Canadian Institutes of Health Research. The authors reported having no relevant conflicts of interest.