Scott M. Berry

Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: A randomized controlled trial

CONTEXT Antiarrhythmic drugs are commonly used for prevention of recurrent atrial fibrillation (AF) despite inconsistent efficacy and frequent adverse effects. Catheter ablation has been proposed as an alternative treatment for paroxysmal AF. OBJECTIVE To determine the efficacy of catheter ablation compared with antiarrhythmic drug therapy (ADT) in treating symptomatic paroxysmal AF. DESIGN, SETTING, AND PARTICIPANTS A prospective, multicenter, randomized (2:1), unblinded, Bayesian-designed study conducted at 19 hospitals of 167 patients who did not respond to at least 1 antiarrhythmic drug and who experienced at least 3 AF episodes within 6 months before randomization. Enrollment occurred between October 25, 2004, and October 11, 2007, with the last follow-up on January 19, 2009. INTERVENTION Catheter ablation (n = 106) or ADT (n = 61), with assessment for effectiveness in a comparable 9-month follow-up period. MAIN OUTCOME MEASURES Time to protocol-defined treatment failure. The proportion of patients who experienced major treatment-related adverse events within 30 days of catheter ablation or ADT was also reported. RESULTS At the end of the 9-month effectiveness evaluation period, 66% of patients in the catheter ablation group remained free from protocol-defined treatment failure compared with 16% of patients treated with ADT. The hazard ratio of catheter ablation to ADT was 0.30 (95% confidence interval, 0.19-0.47; P < .001). Major 30-day treatment-related adverse events occurred in 5 of 57 patients (8.8%) treated with ADT and 5 of 103 patients (4.9%) treated with catheter ablation. Mean quality of life scores improved significantly in patients treated by catheter ablation compared with ADT at 3 months; improvement was maintained during the course of the study. CONCLUSION Among patients with paroxysmal AF who had not responded to at least 1 antiarrhythmic drug, the use of catheter ablation compared with ADT resulted in a longer time to treatment failure during the 9-month follow-up period. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00116428.

Closure of Patent Foramen Ovale versus Medical Therapy after Cryptogenic Stroke

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 prespecified per-protocol and as-treated analyses, with a low rate of associated risks. (Funded by St. Jude Medical; RESPECT ClinicalTrials.gov number, NCT00465270.).

Bayesian Smoothing and Regression Splines for Measurement Error Problems

In the presence of covariate measurement error, estimating a regression function nonparametrically is extremely difficult, the problem being related to deconvolution. Various frequentist approaches exist for this problem, but to date there has been no Bayesian treatment. In this article we describe Bayesian approaches to modeling a flexible regression function when the predictor variable is measured with error. The regression function is modeled with smoothing splines and regression P-splines. Two methods are described for exploration of the posterior. The first, called the iterative conditional modes (ICM), is only partially Bayesian. ICM uses a componentwise maximization routine to find the mode of the posterior. It also serves to create starting values for the second method, which is fully Bayesian and uses Markov chain Monte Carlo (MCMC) techniques to generate observations from the joint posterior distribution. Use of the MCMC approach has the advantage that interval estimates that directly model and adjust for the measurement error are easily calculated. We provide simulations with several nonlinear regression functions and provide an illustrative example. Our simulations indicate that the frequentist mean squared error properties of the fully Bayesian method are better than those of ICM and also of previously proposed frequentist methods, at least in the examples that we have studied.

Novel Intraoperative Molecular Test for Sentinel Lymph Node Metastases in Patients With Early-Stage Breast Cancer

PURPOSE An accurate, intraoperative sentinel lymph node (SLN) test could decrease delayed axillary dissections. Molecular tests may be more sensitive than current intraoperative tests but historically have not been rapid enough and have not been properly validated. We present the results from a large, prospective evaluation of the first rapid molecular SLN test, the Breast Lymph Node (BLN) Assay. METHODS A beta trial (n = 304) to determine the threshold levels of mammaglobin and cytokeratin 19 correlating with metastasis greater than 0.2 mm and a validation trial (n = 416) to validate the threshold cutoffs were conducted. Alternating portions from each SLN were processed for histology and the BLN Assay. RESULTS BLN Assay performance against extensive permanent-section histology verified by central pathology review was similar to that expected of standard permanent-section histology: sensitivity, 87.6%; specificity, 94.2%; positive predictive value, 86.2%; and negative predictive value (NPV), 94.9%. In 319 patients with both frozen-section hematoxylin and eosin results and BLN Assay results, the BLN Assay had higher sensitivity (95.6%) and NPV (98.2%) than frozen section (sensitivity, 85.6%; NPV, 94.5%). The assay can be performed in approximately 36 to 46 minutes for one to three nodes. CONCLUSION The BLN Assay allows a rapid evaluation of 50% of each SLN. Comparison with permanent-section histology on adjacent node pieces evaluated by expert pathologists indicated that the BLN Assay was more sensitive than current intraoperative techniques while maintaining high specificity. These data indicate that the assay may be clinically useful for intraoperative or postoperative axillary lymph node dissection decisions.

Quality of life in patients with advanced renal cell carcinoma given nivolumab versus everolimus in CheckMate 025: a randomised, open-label, phase 3 trial.

BACKGROUND In the phase 3 CheckMate 025 study, previously treated patients with advanced renal cell carcinoma who were randomly assigned to nivolumab had an overall survival benefit compared with those assigned to everolimus. We aimed to compare health-related quality of life (HRQoL) between treatment groups in this trial. METHODS CheckMate 025 was an open-label study done at 146 oncology centres in 24 countries. Patients were randomly assigned to treatment between Oct 22, 2012, and March 11, 2014. Patients with advanced renal cell carcinoma were randomly assigned (1:1, block size of four) to receive nivolumab every 2 weeks or everolimus once per day. The study was stopped early at the planned interim analysis in July, 2015, because the study met its primary endpoint. A protocol amendment permitted patients in the everolimus group to cross over to nivolumab treatment. All patients not on active study therapy are being followed up for survival. At the interim analysis, HRQoL was assessed with the Functional Assessment of Cancer Therapy-Kidney Symptom Index-Disease Related Symptoms (FKSI-DRS) and European Quality of Life (EuroQol)-5 Dimensions (EQ-5D) questionnaires. Prespecified endpoints were to assess, in each treatment group, disease-related symptom progression rate based on the FKSI-DRS and changes in reported global health outcomes based on the EQ-5D. Other endpoints were post hoc. We calculated the proportion of FKSI-DRS questionnaires completed using the number of patients with non-missing data at baseline and at least one post-baseline visit. We defined FKSI-DRS completion as completion of five or more of the nine items in the questionnaire; otherwise data were treated as missing. FKSI-DRS symptom index score was prorated for missing items. We made no adjustments for missing EQ-5D data. We used descriptive statistics and multivariate analyses, including mixed-effects model repeated-measures, for between group comparisons. Analyses were powered according to the original study protocol, and we analysed FKSI-DRS and EQ-5D data for all patients who underwent randomisation and had a baseline assessment and at least one post-baseline assessment. CheckMate 025 is registered with ClinicalTrials.gov, number NCT01668784. FINDINGS HRQoL data were collected at baseline for 362 (88%) of 410 patients in the nivolumab group and 344 (84%) of 411 patients in the everolimus group. The mean difference in FKSI-DRS scores between the nivolumab and everolimus groups was 1·6 (95% CI 1·4-1·9; p<0·0001) with descriptive statistics and 1·7 (1·2-2·1; p<0·0001) with mixed-effects model repeated-measures analysis. In terms of FKSI-DRS score, more patients had a clinically meaningful (ie, an increase of at least 2 points from baseline) HRQoL improvement with nivolumab (200 [55%] of 361 patients) versus everolimus (126 [37%] of 343 patients; p<0·0001). Median time to HRQoL improvement was shorter in patients given nivolumab (4·7 months, 95% CI 3·7-7·5) than in patients given everolimus (median not reached, NE-NE). INTERPRETATION Nivolumab was associated with HRQoL improvement compared with everolimus in previously treated patients with advanced renal cell carcinoma. FUNDING Bristol-Myers Squibb.

Bridging Different Eras in Sports

Abstract This article addresses the problem of comparing abilities of players from different eras in professional sports. We study National Hockey League players, professional golfers, and Major League Baseball players from the perspectives of home run hitting and hitting for average. Within each sport, the careers of the players overlap to some extent. This network of overlaps, or bridges, is used to compare players whose careers took place in different eras. The goal is not to judge players relative to their contemporaries, but rather to compare all players directly. Hence the model that we use is a statistical time machine. We use additive models to estimate the innate ability of players, the effects of aging on performance, and the relative difficulty of each year within a sport. We measure each of these effects separated from the others. We use hierarchical models to model the distribution of players and specify separate distributions for each decade, thus allowing the “talent pool” within each sport...

Bayesian hierarchical modeling of patient subpopulations: efficient designs of Phase II oncology clinical trials.

Background In oncology, the treatment paradigm is shifting toward personalized medicine, where the goal is to match patients to the treatments most likely to deliver benefit. Treatment effects in various subpopulations may provide some information about treatment effects in other subpopulations. Purpose We compare different approaches to Phase II trial design where a new treatment is being investigated in several groups of patients. We compare considering each group in an independent trial to a single trial with hierarchical modeling of the patient groups. Methods We assume four patient groups with different background response rates and simulate operating characteristics of three trial designs, Simon’s Optimal Two-Stage design, a Bayesian adaptive design with frequent interim analyses, and a Bayesian adaptive design with frequent interim analyses and hierarchical modeling across patient groups. Results Simon’s designs are based on 10% Type I and Type II error rates. The independent Bayesian designs are tuned to have similar error rates, but may have a slightly smaller mean sample size due to more frequent interim analyses. Under the null, the mean sample size is 2–4 patients smaller. A hierarchical model across patient groups can provide additional power and a further reduction in mean sample size. Under the null, the addition of the hierarchical model decreases the mean sample size an additional 4–7 patients in each group. Under the alternative hypothesis, power is increased to at least 98% in all groups. Limitations Hierarchical borrowing can make finding a single group in which the treatment is promising, if there is only one, more difficult. In a scenario where the treatment is uninteresting in all but one group, power for that one group is reduced to 65%. When the drug appears promising in some groups and not in others, there is potential for borrowing to inflate the Type I error rate. Conclusions The Bayesian hierarchical design is more likely to correctly conclude efficacy or futility than the other two designs in many scenarios. The Bayesian hierarchical design is a strong design for addressing possibly differential effects in different groups.

A cardiovascular safety study of LibiGel (testosterone gel) in postmenopausal women with elevated cardiovascular risk and hypoactive sexual desire disorder

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.

A patient-level meta-analysis of studies evaluating vagus nerve stimulation therapy for treatment-resistant depression.

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.

The DIAN-TU Next Generation Alzheimer's prevention trial: Adaptive design and disease progression model

The Dominantly Inherited Alzheimer Network Trials Unit (DIAN‐TU) trial is an adaptive platform trial testing multiple drugs to slow or prevent the progression of Alzheimers disease in autosomal dominant Alzheimers disease (ADAD) families. With completion of enrollment of the first two drug arms, the DIAN‐TU now plans to add new drugs to the platform, designated as the Next Generation (NexGen) prevention trial.