"Experts and regulators have recently published recommendations for the appointment and operational procedures of DMCs [1-5] The increasing use and visibility of DMCs has fostered research into their activities There is evidence of heterogeneity in their roles and policies [7-9] The wide range of interim monitoring methods that are available entails considerable variability in DMCs' risk-benefit evaluations[1,2,10] These issues are relevant as the analyses and decisions made by DMCs may be controversial and can influence study validity, particularly in the case of trials terminated early [11-14] "
[Show abstract][Hide abstract] ABSTRACT: Decisions about interim analysis and early stopping of clinical trials, as based on recommendations of Data Monitoring Committees (DMCs), have far reaching consequences for the scientific validity and clinical impact of a trial. Our aim was to evaluate the frequency and quality of the reporting on DMC composition and roles, interim analysis and early termination in pediatric trials.
We conducted a systematic review of randomized controlled clinical trials published from 2005 to 2007 in a sample of four general and four pediatric journals. We used full-text databases to identify trials which reported on DMCs, interim analysis or early termination, and included children or adolescents. Information was extracted on general trial characteristics, risk of bias, and a set of parameters regarding DMC composition and roles, interim analysis and early termination.
110 of the 648 pediatric trials in this sample (17%) reported on DMC or interim analysis or early stopping, and were included; 68 from general and 42 from pediatric journals. The presence of DMCs was reported in 89 of the 110 included trials (81%); 62 papers, including 46 of the 89 that reported on DMCs (52%), also presented information about interim analysis. No paper adequately reported all DMC parameters, and nine (15%) reported all interim analysis details. Of 32 trials which terminated early, 22 (69%) did not report predefined stopping guidelines and 15 (47%) did not provide information on statistical monitoring methods.
Reporting on DMC composition and roles, on interim analysis results and on early termination of pediatric trials is incomplete and heterogeneous. We propose a minimal set of reporting parameters that will allow the reader to assess the validity of trial results.
"[25,26] This is the approach used in STAMPEDE. Many instances of early stopping for benefit appear to occur on a random high [27,28] and the credibility and interpretability of a trial can be adversely affected: caution should be applied in this respect. "
[Show abstract][Hide abstract] ABSTRACT: The multi-arm multi-stage (MAMS) trial is a new paradigm for conducting randomised controlled trials that allows the simultaneous assessment of a number of research treatments against a single control arm. MAMS trials provide earlier answers and are potentially more cost-effective than a series of traditionally designed trials. Prostate cancer is the most common tumour in men and there is a need to improve outcomes for men with hormone-sensitive, advanced disease as quickly as possible. The MAMS design will potentially facilitate evaluation and testing of new therapies in this and other diseases.
STAMPEDE is an open-label, 5-stage, 6-arm randomised controlled trial using MAMS methodology for men with prostate cancer. It is the first trial of this design to use multiple arms and stages synchronously.
The practical and statistical issues faced by STAMPEDE in implementing MAMS methodology are discussed and contrasted with those for traditional trials. These issues include the choice of intermediate and final outcome measures, sample size calculations and the impact of varying the assumptions, the process for moving between trial stages, stopping accrual to each trial arm and overall, and issues around perceived trial complexity.
It is possible to use the MAMS design to initiate and undertake large scale cancer trials. The results from STAMPEDE will not be known for some years but the lessons learned from running a MAMS trial are shared in the hope that other researchers will use this exciting and efficient method to perform further randomised controlled trials.
[Show abstract][Hide abstract] ABSTRACT: As recently demonstrated, random allocation to rosuvastatin results in large relative risk reductions for first cardiovascular events among apparently healthy men and women with low levels of low-density lipoprotein cholesterol but elevated levels of high-sensitivity C-reactive protein. However, whether the absolute risk reduction among such individuals justifies wide application of statin therapy in primary prevention is a controversial issue with broad policy and public health implications.
Absolute risk reductions and consequent number needed to treat (NNT) values were calculated across a range of end points, timeframes, and subgroups using data from Justification for the Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER), a randomized evaluation of rosuvastatin 20 mg versus placebo conducted among 17 802 apparently healthy men and women with low-density lipoprotein cholesterol <130 mg/dL and high-sensitivity C-reactive protein >or=2 mg/L. Sensitivity analyses were also performed to address the potential impact that alternative statin regimens might have on a similar primary prevention population. For the end point of myocardial infarction, stroke, revascularization, or death, the 5-year NNT within JUPITER was 20 (95% CI, 14 to 34). All subgroups had 5-year NNT values for this end point below 50; as examples, 5-year NNT values were 17 for men and 31 for women, 21 for whites and 19 for nonwhites, 18 for those with body mass index <or=25 kg/m(2) and 21 for those with body mass index greater than 25 kg/m(2), 9 and 26 for those with and without a family history of coronary disease, 19 and 22 for those with and without metabolic syndrome, and 14 and 37 for those with estimated Framingham risks greater or less than 10%. For the net vascular benefit end point that additionally included venous thromboembolism, the 5-year NNT was 18 (95% CI, 13 to 29). For the restricted "hard" end point of myocardial infarction, stroke, or death, the 5-year NNT was 29 (95% CI, 19 to 56). In sensitivity analyses addressing the theoretical utility of alternative agents, 5-year NNT values of 38 and 57 were estimated for statin regimens that deliver 75% and 50% of the relative benefit observed in JUPITER, respectively. All of these calculations compare favorably to 5-year NNT values previously reported in primary prevention for the use of statins among hyperlipidemic men (5-year NNT, 40 to 70), for antihypertensive therapy (5-year NNT, 80 to 160), or for aspirin (5-year NNT, >300).
Absolute risk reductions and consequent NNT values associated with statin therapy among those with elevated high-sensitivity C-reactive protein and low low-density lipoprotein cholesterol are comparable if not superior to published NNT values for several widely accepted interventions for primary cardiovascular prevention, including the use of statin therapy among those with overt hyperlipidemia.
clinicaltrials.gov. Identifier NCT00239681.
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