Objective
To analyze why numerous acute stroke treatments were successful in the laboratory but failed in large clinical trials.
Methods
We searched all phase 3 trials of medical treatments for acute ischemic stroke and corresponding early clinical and experimental studies. We compared the overall efficacy and assessed the impact of publication bias and study design on the efficacy. Furthermore, we estimated power and true report probability of experimental studies.
Results
We identified 50 phase 3 trials with 46,008 subjects, 75 early clinical trials with 12,391 subjects, and 209 experimental studies with >7,141 subjects. Three (6%) phase 3, 24 (32%) early clinical, and 143 (69.08%) experimental studies were positive. The mean treatment effect was 0.76 (95% confidence interval [CI] = 0.70–0.83) in experimental studies, 0.87 (95% CI = 0.71–1.06) in early clinical trials, and 1.00 (95% CI = 0.95–1.06) in phase 3 trials. Funnel plot asymmetry and trim‐and‐fill revealed a clear publication bias in experimental studies and early clinical trials. Study design and adherence to quality criteria had a considerable impact on estimated effect sizes. The mean power of experimental studies was 17%. Assuming a bias of 30% and pre‐study odds of 0.5 to 0.7, this leads to a true report probability of <50%.
Interpretation
Pivotal study design differences between experimental studies and clinical trials, including different primary end points and time to treatment, publication bias, neglected quality criteria and low power, contribute to the stepwise efficacy decline of stroke treatments from experimental studies to phase 3 clinical trials. Even under conservative estimates, less than half of published positive experimental stroke studies are truly positive. ANN NEUROL 2020;87:40–51
UroVysion in combination with NMP22 detected more cases than cytology alone, at the expense of a lower specificity. High costs per detected case resulted from a lower BC incidence than in the past when levels of occupational exposure to aromatic amines were higher. Currently, it cannot be recommended to apply these markers for screening in asymptomatic workers. The increase in sensitivity is not balanced by the high costs of UroVysion and the false-positive tests of NMP22.
Urothelial cancer (UCa) is the most predominant cancer of the urinary tract and noninvasive diagnosis using hypermethylation signatures in urinary cells is promising. Here, we assess gender differences in a newly identified set of methylation biomarkers. UCa‐associated hypermethylated sites were identified in urine of a male screening cohort (n = 24) applying Infinium‐450K‐methylation arrays and verified in two separate mixed‐gender study groups (n = 617 in total) using mass spectrometry as an independent technique. Additionally, tissue samples (n = 56) of mixed‐gender UCa and urological controls (UCt) were analyzed. The hypermethylation signature of UCa in urine was specific and sensitive across all stages and grades of UCa and independent on hematuria. Individual CpG sensitivities reached up to 81.3% at 95% specificity. Albeit similar methylation differences in tissue of both genders, differences were less pronounced in urine from women, most likely due to the frequent presence of squamous epithelial cells and leukocytes. Increased repression of methylation levels was observed at leukocyte counts ≥500/μl urine which was apparent in 30% of female and 7% of male UCa cases, further confirming the significance of the relative amounts of cancerous and noncancerous cells in urine. Our study shows that gender difference is a most relevant issue when evaluating the performance of urinary biomarkers in cancer diagnostics. In case of UCa, the clinical benefits of methylation signatures to male patients may outweigh those in females due to the general composition of women's urine. Accordingly, these markers offer a diagnostic option specifically in males to decrease the number of invasive cystoscopies.
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