Niemann C.U.,University of California at San Francisco |
Feiner J.,University of California at San Francisco |
Swain S.,California Transplant Donor Network |
Bunting S.,OneLegacy |
And 7 more authors.
New England Journal of Medicine | Year: 2015
BACKGROUND: Delayed graft function, which is reported in up to 50% of kidney-transplant recipients, is associated with increased costs and diminished long-term graft function. The effect that targeted mild hypothermia in organ donors before organ recovery has on the rate of delayed graft function is unclear. METHODS: We enrolled organ donors (after declaration of death according to neurologic criteria) from two large donation service areas and randomly assigned them to one of two targeted temperature ranges: 34 to 35°C (hypothermia) or 36.5 to 37.5°C (normothermia). Temperature protocols, which were initiated after authorization was obtained for the organ to be donated and for the donor's participation in the study, ended when organ donors left the intensive care unit for organ recovery in the operating room. The primary outcome was delayed graft function in the kidney recipients, which was defined as the requirement for dialysis during the first week after transplantation. Secondary outcomes were the rates of individual organs transplanted in each treatment group and the total number of organs transplanted from each donor. RESULTS: The study was terminated early, on the recommendation of an independent data and safety monitoring board, after the interim analysis showed efficacy of hypothermia. At trial termination, 370 organ donors had been enrolled (180 in the hypothermia group and 190 in the normothermia group). A total of 572 patients received a kidney transplant (285 kidneys from donors in the hypothermia group and 287 kidneys from donors in the normothermia group). Delayed graft function developed in 79 recipients of kidneys from donors in the hypothermia group (28%) and in 112 recipients of kidneys from donors in the normothermia group (39%) (odds ratio, 0.62; 95% confidence interval, 0.43 to 0.92; P = 0.02). CONCLUSIONS: Mild hypothermia, as compared with normothermia, in organ donors after declaration of death according to neurologic criteria significantly reduced the rate of delayed graft function among recipients. Copyright © 2015 Massachusetts Medical Society.
Berry S.M.,Berry Consultants |
Broglio K.,Berry Consultants |
Bunker M.,Cyberonics |
Jayewardene A.,Cyberonics |
And 2 more authors.
Medical Devices: Evidence and Research | Year: 2013
Objective: To compare response and remission rates in depressed patients with chronic treatment-resistant depression (TRD) treated with vagus nerve stimulation (VNS) Therapy® plus treatment as usual (VNS + TAU) or TAU alone in a meta-analysis using Bayesian hierarchical models. Data sources and study selection: Six outpatient, multicenter, clinical trials that have evaluated VNS + TAU or TAU in TRD, including two single-arm studies of VNS + TAU (n = 60 and n = 74), a randomized study of VNS + TAU versus TAU (n = 235), a randomized study of VNS + TAU comparing different VNS stimulation intensities (n = 331), a nonrandomized registry of VNS + TAU versus TAU (n = 636), and a single-arm study of TAU (n = 124) to provide longer-term, control data for comparison with VNS-treated patients. Data extraction: A systematic review of individual patient-level data based on the intent-to-treat principle, including all patients who contributed more than one post-baseline visit. Response was based on the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Clinical Global Impressions scale's Improvement subscale (CGI-I), as these were the two clinician-rated measures common across all or most studies. Remission was based on the MADRS. Results: Outcomes were compared from baseline up to 96 weeks of treatment with VNS + TAU (n = 1035) versus TAU (n = 425). The MADRS response rate for VNS + TAU at 12, 24, 48, and 96 weeks were 12%, 18%, 28%, and 32% versus 4%, 7%, 12%, and 14% for TAU. The MADRS remission rate for VNS + TAU at 12, 24, 48, and 96 weeks were 3%, 5%, 10%, and 14% versus 1%, 1%, 2%, and 4%, for TAU. Adjunctive VNS Therapy was associated with a greater likelihood of response (odds ratio [OR] = 3.19, 95% confidence interval [CI]: 2.12, 4.66) and remission (OR = 4.99, CI: 2.93, 7.76), compared with TAU. For patients who had responded to VNS + TAU at 24 weeks, sustained response was more likely at 48 weeks (OR = 1.98, CI: 1.34, 3.01) and at 96 weeks (OR = 3.42, CI: 1.78, 7.31). Similar results were observed for CGI-I response. Conclusion: For patients with chronic TRD, VNS + TAU has greater response and remission rates that are more likely to persist than TAU. © 2013 Berry et al, publisher and licensee Dove Medical Press Ltd.
White W.B.,University of Connecticut |
Grady D.,University of California at San Francisco |
Giudice L.C.,University of California at San Francisco |
Berry S.M.,Berry Consultants |
And 2 more authors.
American Heart Journal | Year: 2012
Evaluation of the safety of hormonal preparations for the treatment of female sexual dysfunction is important to assess the benefit-to-risk profile of these drugs and has been strongly encouraged by the Food and Drug Administration. LibiGel (Biosante Pharmaceuticals, Inc., Lincolnshire, IL), a low-dose testosterone gel, is under development for the treatment of hypoactive sexual desire disorder (HSDD) in oophorectomized women. To evaluate the long-term effects of LibiGel on risk for cardiovascular (CV) events, breast cancer, and general safety, a randomized, placebo-controlled clinical study using a novel adaptive design to optimize sample size and power is being conducted. The primary end point of the BioSante LibiGel Safety Study (BLISS) is a composite of CV events including death, nonfatal myocardial infarction, nonfatal stroke, coronary revascularization, hospitalized unstable angina, and venous thromboembolic events. Breast cancer is a coprimary end point. Postmenopausal women (both surgically and naturally) with HSDD and increased risk for CV events will be followed up for up to 5 years postrandomization with an interim data analysis for regulatory approval after the last woman enrolled has been on therapy for at least 12 months. Determination of the number of subjects to enroll is based on an adaptive design that uses interim data to estimate the predictive probability of study success. In agreement with the Food and Drug Administration, LibiGel will be declared safe if the upper limit of the 97.2% CI of the hazard ratio is ≤2.0 or the upper bound of the 97.2% CI for the absolute difference between CV event rates per 100 person-years is ≤1% and the observed hazard ratio is ≤2.0. The BLISS study will define the CV safety profile of low-dose testosterone therapy in the formulation of LibiGel for postmenopausal women with HSDD, and the trial design may provide a paradigm for studies that aim to document long-term safety when the proposed outcome under study is an uncommon adverse event. © 2012 Mosby, Inc. All rights reserved.
Carroll J.D.,University of Colorado at Denver |
Saver J.L.,University of California at Los Angeles |
Thaler D.E.,Tufts University |
Smalling R.W.,Texas Heart Institute |
And 4 more authors.
New England Journal of Medicine | Year: 2013
BACKGROUND: Whether closure of a patent foramen ovale is effective in the prevention of recurrent ischemic stroke in patients who have had a cryptogenic stroke is unknown. We conducted a trial to evaluate whether closure is superior to medical therapy alone in preventing recurrent ischemic stroke or early death in patients 18 to 60 years of age. METHODS: In this prospective, multicenter, randomized, event-driven trial, we randomly assigned patients, in a 1:1 ratio, to medical therapy alone or closure of the patent foramen ovale. The primary results of the trial were analyzed when the target of 25 primary end-point events had been observed and adjudicated. RESULTS: We enrolled 980 patients (mean age, 45.9 years) at 69 sites. The medical-therapy group received one or more antiplatelet medications (74.8%) or warfarin (25.2%). Treatment exposure between the two groups was unequal (1375 patient-years in the closure group vs. 1184 patient-years in the medical-therapy group, P=0.009) owing to a higher dropout rate in the medical-therapy group. In the intention-to-treat cohort, 9 patients in the closure group and 16 in the medical-therapy group had a recurrence of stroke (hazard ratio with closure, 0.49; 95% confidence interval [CI], 0.22 to 1.11; P=0.08). The between-group difference in the rate of recurrent stroke was significant in the prespecified per-protocol cohort (6 events in the closure group vs. 14 events in the medical-therapy group; hazard ratio, 0.37; 95% CI, 0.14 to 0.96; P=0.03) and in the as-treated cohort (5 events vs. 16 events; hazard ratio, 0.27; 95% CI, 0.10 to 0.75; P=0.007). Serious adverse events occurred in 23.0% of the patients in the closure group and in 21.6% in the medical-therapy group (P=0.65). Procedure-related or device-related serious adverse events occurred in 21 of 499 patients in the closure group (4.2%), but the rate of atrial fibrillation or device thrombus was not increased. CONCLUSIONS: In the primary intention-to-treat analysis, there was no significant benefit associated with closure of a patent foramen ovale in adults who had had a cryptogenic ischemic stroke. However, closure was superior to medical therapy alone in the pre-specified per-protocol and as-treated analyses, with a low rate of associated risks. Copyright © 2013 Massachusetts Medical Society.
Wiens B.L.,Alcon |
Lystig T.C.,Medtronic |
Berry S.M.,Berry Consultants
Therapeutic Innovation and Regulatory Science | Year: 2014
Clinical trials in the development of new medical device products are in many ways analogous to clinical trials in the development of new drug or biologic products. However, the differences are important and not always intuitive to a statistician with only experience supporting development of drug and biologic products. In this paper we discuss some of the interesting differences with focus on the statistical innovation that is coming out of the medical device area. We discuss examples of the differences in clinical trial design and effects of these differences on clinical development programs. © The Author(s) 2013.
Saville B.R.,Vanderbilt University |
Connor J.T.,Berry Consultants |
Connor J.T.,University of Central Florida |
Ayers G.D.,Vanderbilt University |
Alvarez J.,Vanderbilt University
Clinical Trials | Year: 2014
Background Bayesian predictive probabilities can be used for interim monitoring of clinical trials to estimate the probability of observing a statistically significant treatment effect if the trial were to continue to its predefined maximum sample size. Purpose We explore settings in which Bayesian predictive probabilities are advantageous for interim monitoring compared to Bayesian posterior probabilities, p-values, conditional power, or group sequential methods. Results For interim analyses that address prediction hypotheses, such as futility monitoring and efficacy monitoring with lagged outcomes, only predictive probabilities properly account for the amount of data remaining to be observed in a clinical trial and have the flexibility to incorporate additional information via auxiliary variables. Limitations Computational burdens limit the feasibility of predictive probabilities in many clinical trial settings. The specification of prior distributions brings additional challenges for regulatory approval. Conclusions The use of Bayesian predictive probabilities enables the choice of logical interim stopping rules that closely align with the clinical decision-making process. © 2014 The Author(s).
Connor J.T.,Berry Consultants |
Connor J.T.,University of Central Florida |
Elm J.J.,Medical University of South Carolina |
Broglio K.R.,Berry Consultants
Journal of Clinical Epidemiology | Year: 2013
Objective: We present a novel Bayesian adaptive comparative effectiveness trial comparing three treatments for status epilepticus that uses adaptive randomization with potential early stopping. Study Design and Setting: The trial will enroll 720 unique patients in emergency departments and uses a Bayesian adaptive design. Results: The trial design is compared to a trial without adaptive randomization and produces an efficient trial in which a higher proportion of patients are likely to be randomized to the most effective treatment arm while generally using fewer total patients and offers higher power than an analogous trial with fixed randomization when identifying a superior treatment. Conclusion: When one treatment is superior to the other two, the trial design provides better patient care, higher power, and a lower expected sample size. © 2013 Elsevier Inc. All rights reserved.
Skrivanek Z.,Eli Lilly and Company |
Gaydos B.L.,Eli Lilly and Company |
Chien J.Y.,Eli Lilly and Company |
Geiger M.J.,Regeneron Pharmaceuticals Inc |
And 6 more authors.
Diabetes, Obesity and Metabolism | Year: 2014
Aims: AWARD-5 was an adaptive, seamless, double-blind study comparing dulaglutide, a once-weekly glucagon-like peptide-1 (GLP-1) receptor agonist, with placebo at 26weeks and sitagliptin up to 104weeks. The study also included a dose-finding portion whose results are presented here. Methods: Type 2 diabetes (T2D) patients on metformin were randomized 3:1:1 to seven dulaglutide doses, sitagliptin (100mg), or placebo. A Bayesian algorithm was used for randomization and dose selection. Patients were adaptively randomized to dulaglutide doses using available data on the basis of a clinical utility index (CUI) of glycosylated haemoglobin A1c (HbA1c) versus sitagliptin at 52weeks and weight, pulse rate (PR) and diastolic blood pressure (DBP) versus placebo at 26weeks. The algorithm randomly assigned patients until two doses were selected. Results: Dulaglutide 1.5mg was determined to be the optimal dose. Dulaglutide 0.75mg met criteria for the second dose. Dulaglutide 1.5mg showed the greatest Bayesian mean change from baseline (95% credible interval) in HbA1c versus sitagliptin at 52weeks -0.63 (-0.98 to -0.20)%. Dulaglutide 2.0mg showed the greatest placebo-adjusted mean change in weight [-1.99 (-2.88 to -1.20)kg] and in PR [0.78 (-2.10 to 3.80)bpm]. Dulaglutide 1.5mg showed the greatest placebo-adjusted mean change in DBP [-0.62 (-3.40 to 2.30)mmHg]. Conclusions: The Bayesian algorithm allowed for an efficient exploration of a large number of doses and selected dulaglutide doses of 1.5 and 0.75mg for further investigation in this trial. © 2014 John Wiley & Sons Ltd.
Quintana M.A.,Berry Consultants |
Conti D.V.,University of Southern California
Statistics in Medicine | Year: 2013
We are interested in developing integrative approaches for variable selection problems that incorporate external knowledge on a set of predictors of interest. In particular, we have developed an integrative Bayesian model uncertainty (iBMU) method, which formally incorporates multiple sources of data via a second-stage probit model on the probability that any predictor is associated with the outcome of interest. Using simulations, we demonstrate that iBMU leads to an increase in power to detect true marginal associations over more commonly used variable selection techniques, such as least absolute shrinkage and selection operator and elastic net. In addition, iBMU leads to a more efficient model search algorithm over the basic BMU method even when the predictor-level covariates are only modestly informative. The increase in power and efficiency of our method becomes more substantial as the predictor-level covariates become more informative. Finally, we demonstrate the power and flexibility of iBMU for integrating both gene structure and functional biomarker information into a candidate gene study investigating over 50 genes in the brain reward system and their role with smoking cessation from the Pharmacogenetics of Nicotine Addiction and Treatment Consortium. © 2013 John Wiley & Sons, Ltd.
Viele K.,Berry Consultants
Pharmaceutical statistics | Year: 2014
Clinical trials rarely, if ever, occur in a vacuum. Generally, large amounts of clinical data are available prior to the start of a study, particularly on the current study's control arm. There is obvious appeal in using (i.e., 'borrowing') this information. With historical data providing information on the control arm, more trial resources can be devoted to the novel treatment while retaining accurate estimates of the current control arm parameters. This can result in more accurate point estimates, increased power, and reduced type I error in clinical trials, provided the historical information is sufficiently similar to the current control data. If this assumption of similarity is not satisfied, however, one can acquire increased mean square error of point estimates due to bias and either reduced power or increased type I error depending on the direction of the bias. In this manuscript, we review several methods for historical borrowing, illustrating how key parameters in each method affect borrowing behavior, and then, we compare these methods on the basis of mean square error, power and type I error. We emphasize two main themes. First, we discuss the idea of 'dynamic' (versus 'static') borrowing. Second, we emphasize the decision process involved in determining whether or not to include historical borrowing in terms of the perceived likelihood that the current control arm is sufficiently similar to the historical data. Our goal is to provide a clear review of the key issues involved in historical borrowing and provide a comparison of several methods useful for practitioners. Copyright © 2013 John Wiley & Sons, Ltd.