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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

From: Comparison of treatment effect sizes from pivotal and postapproval trials of novel therapeutics approved by the FDA based on surrogate markers of disease: a meta-epidemiological study

  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
  1. aAnalyses based on McNemar’s exact test
  2. bAnalyses based on Wilcoxon signed-rank test
  3. ITT intention to treat (when available, all subjects randomized), mITT modified intention to treat (all subjects randomized that received at least one treatment)
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