Proportion of Phase-2 Cancer Trials That Are RCT’s
Using the advanced search tool at www.clinicaltrials.gov, I searched for
interventional studies whose indication was cancer, carcinoma, adenoma,
leukemia, or lymphoma. To find all such trials with a given phase, the
Search Term field was left blank (first column in the table below); to find
the randomized subset of such trials for a given phase, the Search Term
field was set to “randomized” (second column in the table below).
To exclude trials that are randomized but not controlled (e.g. trials with
randomization to multiple doses of the same treatment regimen), the Search
Term field was set to “randomized AND uncontrolled” (third column in table
below). The number of randomized controlled trials for a given phase, shown
in the fourth (rightmost) column of the table, was determined by subtracting
the third column from the second column.*
To exclude phase-1/2 trials, I subtracted the number of trials returned by
the search query when checking the “Phase I” box from the number of trials
returned by the search query when checking the “Phase I” and “Phase II”
boxes. The result of this subtraction, shown in the third row of the table
below, is the number of phase-2 trials not designated as phase-1/2.
The number of interest is the result of dividing the fourth column of the
third row by the first column of the third row: 2169 / 8973 = 24.2%.
Randmzd Randmzd
All Randmzd Uncntrld Contrld
Phase Studies Studies Studies Studies
I,II,I/II 14,597 2,885 212 2,673
Less I,I/II 5,624 561 57 504
============== ====== ===== === =====
II (excl I/II) 8,973 2,324 155 2,169
*Some randomized trials in the clinicaltrials.gov database are not
designated as either “controlled” or “uncontrolled”; I included these
trials because the vast majority of them have an active or placebo
control arm.
