Others thought healthy volunteers may drop out of trials because of lack of interest in the trial.
Unfortunately, most of these studies were limited to phase I and phase II trials because of lack of efficacy and/or hepatotoxicity.
Notwithstanding, several clinical studies using the same compound in tumors exhibiting Hh overactivity without identified Hh mutations have resulted in discouraging outcome and discontinuation of the trials because of lack of objective response [ 2].
Doxorubicin was used in this trial because of lack of preclinical and phase I clinical data with PLD.
A futility analysis will also be performed at each of these interim analyses, permitting early termination of the trial for lack of efficacy.
The majority of evoked and event-related potentials studies in migraine have shown two abnormalities: increased amplitudes of averages of large numbers of trials and lack of habituation in successive trial blocks during the pain-free phase, with the ictal normalization of evoked potential amplitudes and habituation [15].
From a broader perspective, the greatest limitation of this study is characteristic of all open trials: the lack of standard features of clinical trials such as placebo controls, randomization, and blinding of raters.
Whereas advances in minimally invasive surgery have made laparoscopic staging technically feasible in stage I epithelial ovarian cancer, the practice remains controversial because of an absence of randomized trials and lack of high-quality observational studies demonstrating equivalent outcomes.
First came a long line of clinical trials suggesting lack of benefit and potential harm from high doses of select nutrients.
A number of obstacles remain including regulatory issues, length of clinical trials, the lack of validation and consensus on new biological markers, and the fact that recent developments in more effective imaging technology are not yet commonly used.
