Magnitude of Clinical Benefit of Cancer Drugs Approved by the US Food and Drug Administration

Abstract

Background: It is uncertain whether drugs approved by the US Food and Drug Administration (FDA) have clinically meaningful benefit as determined by validated scales such as the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS).

Methods: We searched the Drugs@FDA website for applications of anticancer drugs from January 2006 to December 2016. Study characteristics, outcomes, and regulatory pathways were collected from drug labels and reports of registration trials. For randomized controlled trials (RCTs), ESMO-MCBS grades were applied. Meaningful benefit was defined as a grade of A or B for (neo)adjuvant intent and 4 or 5 for palliative intent. All statistical tests were two-sided.

Results: We identified 63 individual drugs for 118 indications. These were supported by 135 studies, among which were 105 RCTs for which ESMO-MCBS could be applied. Only 46 (43.8%) met the ESMO-MCBS meaningful benefit threshold (100% of (neo)adjuvant trials and 38.8% of palliative trials). In palliative therapy trials, meaningful ESMO-MCBS grades were associated with phase III trials (compared with phase II; odds ratio [OR] = 38.45, 95% confidence interval [CI] = 3.27 to 452.00, P = .004), those with overall survival as their primary end point (compared with intermediate end points; OR = 8.28, 95% CI = 2.49 to 27.50, P = .001) and trials of targeted drugs with companion diagnostics (OR = 11.62, 95% CI = 2.95 to 45.78, P < .001). Over time, there has been an increase in the number of trials meeting the ESMO-MCBS threshold (Ptrend = .04). There were insufficient (neo)adjuvant studies to perform statistical analysis.

Conclusions: The number of trials meeting the ESMO-MCBS threshold for clinical benefit has improved over time. However, fewer than half of RCTs supporting FDA approval meet the threshold for clinically meaningful benefit.