Trials of the addition of aromatase inhibitors after 5 years of tamoxifen have also shown important recurrence reductions [ 8], but again the full benefit may not as yet have been observed and crossover of the control arm to receive an AI makes this difficult to evaluate [ 9].
The finding of greater improvements in patients with severe versus moderate disease 10 was also replicated after crossover of the controls (−26 v −13 events/hour, P=0.02).
(7) The reasons for the lack of survival benefit with molecularly targeted therapy are unclear but may include crossover of patients from control to experimental arms and/or administration of additional systemic treatment(s) post-study, which confound analysis and interpretation of OS data.
Reviewer #3: There is no question that the manuscript of Ziolkowski et al. is of interest as it is challenging current views of crossover control, not only in plants.
Schools are randomly allocated to one of the four sequences for time of crossover from control to intervention phase using a computer-generated list of random numbers.
We review the various means of crossover control that have been described or proposed.
Here, we present a microarray-based method to analyze multiple aspects of crossover control simultaneously and rapidly, at high resolution, genome-wide, and on a cell-by-cell basis.
Second, there was crossover of 10% of the control group to IABP therapy and a more frequent use of left ventricular assist devices (LVADs) in control patients (7.4% versus 3.7%), and both of these factors might decrease the control group mortality if IABP and LVAD use is beneficial.
Interim analysis of the most recent phase III study in the newly diagnosed setting showed a significant improvement of outcomes leading to a crossover of subjects from the control arm to the experimental arm of the trial [ 7].
Acute effects of weekly respiratory virus activity on IMD risk were evaluated using a matched-period case-crossover design with random directionality of control selection.
