Table 2.
Characteristics of published, superiority, randomized, pivotal trials of novel drugs first approved by the FDA between 2005 and 2012 based on trials using surrogate markers of disease as primary endpoints with at least one postapproval match
| Pivotal trials | Postapproval trials | ||
|---|---|---|---|
| Characteristics | P valuea | ||
| Total studies | 43 (100.0) | 43 (100.0) | |
| Allocation | |||
| Double or triple blind | 39 (90.7) | 31 (72.1) | 0.008 |
| Single blinded or open label | 4 (9.3) | 12 (27.9) | |
| Number of arms | |||
| Median (interquartile range) | 3 (2, 4) | 2 (2, 4) | 0.14b |
| Comparator options | |||
| Active only | 9 (20.9) | 17 (39.5) | 0.04 |
| Placebo only or active and placebo | 34 (79.1) | 26 (61.5) | |
| Center status | |||
| Multicenter | 43 (100.0) | 40 (93.0) | 0.25 |
| Single center | 0 | 3 (7.0) | |
| Funder type | |||
| Industry or mixed funding that includes industry | 40 (93.0) | 38 (88.4) | 0.69 |
| All others (non-profit, government, mixed non-industry, none, not specified) | 3 (7.0) | 5 (11.6) | |
| Sample size | |||
| Total ITT or mITT, median (interquartile range) | 672 (390, 822) | 395 (154, 735) | 0.02b |
| Study duration | |||
| Duration in weeks, median (interquartile range) | 24 (10, 26) | 24 (12, 26) | 0.57b |
aAnalyses based on McNemar’s exact test
bAnalyses based on Wilcoxon signed-rank test
ITT intention to treat (when available, all subjects randomized), mITT modified intention to treat (all subjects randomized that received at least one treatment)