Hypothermia or Machine Perfusion in Kidney Donors.

BACKGROUND: Therapeutic hypothermia in brain-dead organ donors has been shown to reduce delayed graft function in kidney recipients after transplantation. Data are needed on the effect of hypothermia as compared with machine perfusion on outcomes after kidney transplantation. METHODS: At six organ-procurement facilities in the United States, we randomly assigned brain-dead kidney donors to undergo therapeutic hypothermia (hypothermia group), ex situ kidney hypothermic machine perfusion (machine-perfusion group), or both (combination-therapy group). The primary outcome was delayed graft function in the kidney transplant recipients (defined as the initiation of dialysis during the first 7 days after transplantation). We also evaluated whether hypothermia alone was noninferior to machine perfusion alone and whether the combination of both methods was superior to each of the individual therapies. Secondary outcomes included graft survival at 1 year after transplantation. RESULTS: From 725 enrolled donors, 1349 kidneys were transplanted: 359 kidneys in the hypothermia group, 511 in the machine-perfusion group, and 479 in the combined-therapy group. Delayed graft function occurred in 109 patients (30%) in the hypothermia group, in 99 patients (19%) in the machine-perfusion group, and in 103 patients (22%) in the combination-therapy group. Adjusted risk ratios for delayed graft function were 1.72 (95% confidence interval [CI], 1.35 to 2.17) for hypothermia as compared with machine perfusion, 1.57 (95% CI, 1.26 to 1.96) for hypothermia as compared with combination therapy, and 1.09 (95% CI, 0.85 to 1.40) for combination therapy as compared with machine perfusion. At 1 year, the frequency of graft survival was similar in the three groups. A total of 10 adverse events were reported, including cardiovascular instability in 9 donors and organ loss in 1 donor owing to perfusion malfunction. CONCLUSIONS: Among brain-dead organ donors, therapeutic hypothermia was inferior to machine perfusion of the kidney in reducing delayed graft function after transplantation. The combination of hypothermia and machine perfusion did not provide additional protection. (Funded by Arnold Ventures; ClinicalTrials.gov number, NCT02525510.).

Bayesian adaptive design for clinical trials in Duchenne muscular dystrophy.

A Bayesian adaptive design is proposed for a clinical trial in Duchenne muscular dystrophy. The trial was designed to demonstrate treatment efficacy on an ambulatory-based clinical endpoint and to identify early success on a biomarker (dystrophin protein levels) that can serve as a basis for accelerated approval in the United States. The trial incorporates placebo augmentation using placebo data from past clinical trials. A thorough simulation study was conducted to understand the operating characteristics of the trial. This trial design was selected for the US FDA Complex Innovative Trial Design Pilot Meeting Program and the experience in that program is summarized.

A subset analysis of a phase II trial evaluating the use of DFMO as maintenance therapy for high-risk neuroblastoma.

Neuroblastoma is a sympathetic nervous system tumor, primarily presenting in children under 6 years of age. The long-term prognosis for patients with high-risk neuroblastoma (HRNB) remains poor despite aggressive multimodal therapy. This report provides an update to a phase II trial evaluating DFMO as maintenance therapy in HRNB. Event-free survival (EFS) and overall survival (OS) of 81 subjects with HRNB treated with standard COG induction, consolidation and immunotherapy followed by 2 years of DFMO on the NMTRC003/003b Phase II trial were compared to a historical cohort of 76 HRNB patients treated at Beat Childhood Cancer Research Consortium (BCC) hospitals who were disease-free after completion of standard upfront therapy and did not receive DFMO. The 2- and 5-year EFS were 86.4% [95% confidence interval (CI) 79.3%-94.2%] and 85.2% [77.8%-93.3%] for the NMTRC003/003b subset vs 78.3% [69.5%-88.3%] and 65.6% [55.5%-77.5%] for the historical control group. The 2- and 5-year OS were 98.8% [96.4-100%] and 95.1% [90.5%-99.9%] vs 94.4% [89.3%-99.9%] and 81.6% [73.0%-91.2%], respectively. DFMO maintenance for HRNB after completion of standard of care therapy was associated with improved EFS and OS relative to historical controls treated at the same institutions. These results support additional investigations into the potential role of DFMO in preventing relapse in HRNB.

Comparison of methods for control allocation in multiple arm studies using response adaptive randomization.

BACKGROUND/AIMS: Response adaptive randomization has many polarizing properties in two-arm settings comparing control to a single treatment. The generalization of these features to the multiple arm setting has been less explored, and existing comparisons in the literature reach disparate conclusions. We investigate several generalizations of two-arm response adaptive randomization methods relating to control allocation in multiple arm trials, exploring how critiques of response adaptive randomization generalize to the multiple arm setting. METHODS: We perform a simulation study to investigate multiple control allocation schemes within response adaptive randomization, comparing the designs on metrics such as power, arm selection, mean square error, and the treatment of patients within the trial. RESULTS: The results indicate that the generalization of two-arm response adaptive randomization concerns is variable and depends on the form of control allocation employed. The concerns are amplified when control allocation may be reduced over the course of the trial but are mitigated in the methods considered when control allocation is maintained or increased during the trial. In our chosen example, we find minimal advantage to increasing, as opposed to maintaining, control allocation; however, this result reflects an extremely limited exploration of methods for increasing control allocation. CONCLUSION: Selection of control allocation in multiple arm response adaptive randomization has a large effect on the performance of the design. Some disparate comparisons of response adaptive randomization to alternative paradigms may be partially explained by these results. In future comparisons, control allocation for multiple arm response adaptive randomization should be chosen to keep in mind the appropriate match between control allocation in response adaptive randomization and the metric or metrics of interest.

Comparison of response adaptive randomization features in multiarm clinical trials with control.

We investigate multiple features of response adaptive randomization (RAR) in the context of a multiple arm randomized trial with control, where the primary goal is the identification of the best arm for use in a broader patient population. We maintain constant control allocation and vary the length of time until RAR is started, interim frequency, the underlying quantity used to calculate the randomization probabilities, and a threshold resulting in temporary arm dropping. We evaluate the designs on five metrics measuring benefit to the internal trial population, the future external population, and statistical estimation. Our results indicate these features have minimal interaction within the space explored, with preference for earlier activation of RAR, more frequent interim analyses, randomizing in proportion to the probability each arm is the best, and aggressive thresholding for temporarily dropping arms. The results illustrate useful principles for maximizing the benefit of RAR in practice.

Modeling the economic benefit of targeted mild hypothermia in deceased donor kidney transplantation.

Delayed graft function (DGF) in kidney transplant significantly increases inpatient and outpatient cost. Targeted, mild hypothermia in organ donors after neurologic determination of death significantly reduced the rate of DGF in a recent randomized controlled clinical trial. To assess the potential economic benefit of national implementation of donor hypothermia, rates of reduction DGF were combined with estimates of the impact of DGF on hospital cost and total health expenditure for standard and extended criteria donor organs (SCD and ECD). DGF increases the cost of the transplant episode by $9487 for ECD transplant and $10 342 for SCD transplant. Medicare recipients with DGF incur an additional $18 513 spending for ECD and $14 948 in SCD transplants over the first year. An absolute reduction in DGF rate after kidney transplantation consistent with trial results (ECD 25%, SCD 7%) has the potential to lower annual hospital cost for kidney transplant by $13 178 746 and annual Medicare spending by $20 970 706 compared to standard donor management practice using static cold storage. Targeted mild hypothermia improves care of renal transplant patients by safely reducing DGF rates in both ECD and SCD transplant. Broader application of this safe, effective, and low-cost intervention could reduce healthcare expenditures for providers and insurers.

Therapeutic Hypothermia in Deceased Organ Donors and Kidney-Graft Function.

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. (Funded by the Health Resources and Services Administration; ClinicalTrials.gov number, NCT01680744.).

Phase 3 adaptive trial design options in treatment of complicated urinary tract infection.

New antimicrobial drugs for treatment of complicated urinary tract infection (cUTI) are generally assessed in randomized, double-blind, noninferiority clinical trials. Robust historical data for the active comparator inform on treatment effect estimation, yet typically do not substitute for the active comparator data in the proposed trial. We report design options for a phase 3 trial of cUTI using a Bayesian hierarchical model and historical data from 2 well-executed phase 3 registrational trials of doripenem. The methodology is directly applicable to other phase 3 noninferiority settings. In addition to the research design application, we provide a novel methodology for assessing the robustness of type I error control. The model borrows heavily from the prior data when the current active comparator parameter estimate approximated the historical estimate. In contrast, the model had restricted borrowing when the 2 estimates were very different. The alternative trial design, with or without the inclusion of futility stopping criteria, provides a framework for future cUTI phase 3 trials.

Using Bayesian Adaptive Trial Designs for Comparative Effectiveness Research: A Virtual Trial Execution.

BACKGROUND: Bayesian and adaptive clinical trial designs offer the potential for more efficient processes that result in lower sample sizes and shorter trial durations than traditional designs. OBJECTIVE: To explore the use and potential benefits of Bayesian adaptive clinical trial designs in comparative effectiveness research. DESIGN: Virtual execution of ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) as if it had been done according to a Bayesian adaptive trial design. SETTING: Comparative effectiveness trial of antihypertensive medications. PATIENTS: Patient data sampled from the more than 42 000 patients enrolled in ALLHAT with publicly available data. MEASUREMENTS: Number of patients randomly assigned between groups, trial duration, observed numbers of events, and overall trial results and conclusions. RESULTS: The Bayesian adaptive approach and original design yielded similar overall trial conclusions. The Bayesian adaptive trial randomly assigned more patients to the better-performing group and would probably have ended slightly earlier. LIMITATIONS: This virtual trial execution required limited resampling of ALLHAT patients for inclusion in RE-ADAPT (REsearch in ADAptive methods for Pragmatic Trials). Involvement of a data monitoring committee and other trial logistics were not considered. CONCLUSION: In a comparative effectiveness research trial, Bayesian adaptive trial designs are a feasible approach and potentially generate earlier results and allocate more patients to better-performing groups. PRIMARY FUNDING SOURCE: National Heart, Lung, and Blood Institute.

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.

Not too big, not too small: a goldilocks approach to sample size selection.

We present a Bayesian adaptive design for a confirmatory trial to select a trial's sample size based on accumulating data. During accrual, frequent sample size selection analyses are made and predictive probabilities are used to determine whether the current sample size is sufficient or whether continuing accrual would be futile. The algorithm explicitly accounts for complete follow-up of all patients before the primary analysis is conducted. We refer to this as a Goldilocks trial design, as it is constantly asking the question, "Is the sample size too big, too small, or just right?" We describe the adaptive sample size algorithm, describe how the design parameters should be chosen, and show examples for dichotomous and time-to-event endpoints.

A Systematic Review of Adaptive Seamless Clinical Trials for Late-Phase Oncology Development.

INTRODUCTION: Although oncology has seen large scientific and clinical advances over the last decade, it also has one of the lowest success rates for novel agents across therapeutic areas. Adaptive clinical trial design has been a popular option for increasing clinical trial efficiency and the chances of trial success. Seamless clinical trial design are studies in which two or more clinical trial phases are combined into a single study with a pre-specified transition between stages. This integration of phases may enhance efficiency. METHODS: To understand the precedent for the use of seamless designs, this working group was formed to conduct a comprehensive literature search on seamless clinical trials conducted with confirmatory intent in oncology. Trial design features were extracted into a database and analyzed with descriptive statistics. RESULTS: A literature search identified 68 clinical trials meeting inclusion and exclusion criteria. The most common design feature was a gate on treatment efficacy, where the trial would only proceed to the second stage if sufficient efficacy was observed in the first. The next most common feature was a selection of a dose or treatment regimen. Inferentially and operationally seamless designs were approximately equally represented. DISCUSSION: Key statistical considerations for seamless phase II/III designs include optimizing design choices by evaluating and comparing operating characteristics across design alternatives as well as showing control of overall Type I error rates. Executing the transition between phases should be evaluated for issues related to accrual, drug production, and procedures to maintain trial integrity. CONCLUSIONS: While there are unique statistical, regulatory, and operational considerations for seamless designs they are also uniquely suited to many development settings. These include, for example, addressing dose selection under FDA's Project Optimus and addressing the growing use of biomarkers and personalized medicine approaches in cancer treatment.

Therapeutic Hypothermia in Low-Risk Nonpumped Brain-Dead Kidney Donors: A Randomized Clinical Trial.

Importance: Delayed graft function in kidney-transplant recipients is associated with increased financial cost and patient burden. In donors with high Kidney Donor Profile Index whose kidneys are not pumped, therapeutic hypothermia has been shown to confer a protective benefit against delayed graft function. Objective: To determine whether hypothermia is superior to normothermia in preventing delayed graft function in low-risk nonpumped kidney donors after brain death. Design, Setting, and Participants: In a multicenter randomized clinical trial, brain-dead kidney donors deemed to be low risk and not requiring machine perfusion per Organ Procurement Organization protocol were prospectively randomized to hypothermia (34.0-35 °C) or normothermia (36.5-37.5 °C) between August 10, 2017, and May 21, 2020, across 4 Organ Procurement Organizations in the US (Arizona, Upper Midwest, Pacific Northwest, and Texas). The final analysis report is dated June 15, 2022, based on the data set received from the United Network for Organ Sharing on June 2, 2021. A total of 509 donors (normothermia: n = 245 and hypothermia: n = 236; 1017 kidneys) met inclusion criteria over the study period. Intervention: Donor hypothermia (34.0-35.0 °C) or normothermia (36.5-37.5 °C). Main Outcomes and Measures: The primary outcome was delayed graft function in the kidney recipients, defined as the need for dialysis within the first week following kidney transplant. The primary analysis follows the intent-to-treat principle. Results: A total of 934 kidneys were transplanted from 481 donors, of which 474 were randomized to the normothermia group and 460 to the hypothermia group. Donor characteristics were similar between the groups, with overall mean (SD) donor age 34.2 (11.1) years, and the mean donor creatinine level at enrollment of 1.03 (0.53) mg/dL. There was a predominance of Standard Criteria Donors (98% in each treatment arm) with similar low mean (SD) Kidney Donor Profile Index (normothermia: 28.99 [20.46] vs hypothermia: 28.32 [21.9]). Cold ischemia time was similar in the normothermia and hypothermia groups (15.99 [7.9] vs 15.45 [7.63] hours). Delayed graft function developed in 87 of the recipients (18%) in the normothermia group vs 79 (17%) in the hypothermia group (adjusted odds ratio, 0.92; 95% CI, 0.64-1.33; P = .66). Conclusions and Relevance: The findings of this study suggest that, in low-risk non-pumped kidneys from brain-dead kidney donors, therapeutic hypothermia compared with normothermia does not appear to prevent delayed graft function in kidney transplant recipients. Trial Registration: ClinicalTrials.gov Identifier: NCT02525510.

Unlocking the Potential: A Systematic Review of Master Protocol in Pediatrics.

The use of master protocols allows for innovative approaches to clinical trial designs, potentially enabling new approaches to operations and analytics and creating value for patients and drug developers. Pediatric research has been conducted for many decades, but the use of novel designs such as master protocols in pediatric research is not well understood. This study aims to provide a systematic review on the utilization of master protocols in pediatric drug development. A search was performed in September 2022 using two data sources (PubMed and ClinicalTrials.gov) and included studies conducted in the past10 years. General study information was extracted such as study type, study status, therapeutic area, and clinical trial phase. Study characteristics that are specific to pediatric studies (such as age of the participants and pediatric drug dosing) and important study design elements (such as number of test drug arms and whether randomization and/or concurrent control was used) were also collected. Our results suggest that master protocol studies are being used in pediatrics, with platform and basket trials more common than umbrella trials. Most of this experience is in oncology and early phase studies. There is a rise in the use starting in 2020, largely in oncology and COVID-19 trials. However, adoption of master protocols in pediatric clinical research is still on a small scale and could be substantially expanded. Work is required to further understand the barriers in implementing pediatric master protocols, from setting up infrastructure to interpreting study findings.

Use of Seamless Study Designs in Oncology Clinical Development- A Survey Conducted by IDSWG Oncology Sub-team.

Seamless study designs have the potential to accelerate clinical development. The use of innovative seamless designs has been increasing in the oncology area; however, while the concept of seamless designs becomes more popular and accepted, many challenges remain in both the design and conduct of these trials. This may be especially true when seamless designs are used in late phase development supporting regulatory decision-making. The Innovative Design Scientific Working Group (IDSWG) Oncology team conducted a survey to understand the current use of seamless study designs for registration purposes in oncology clinical development. The survey was designed to provide insights into the benefits and to identify the roadblocks. A total of 16 questions were included in the survey that was distributed using the ASA Biopharmaceutical Section and IDSWG email listings from August to September 2022. A total of 51 responses were received, with 39 (76%) respondents indicating that their organizations had seamless oncology studies in planning or implementation for registration purposes. Detailed survey results are presented in the manuscript. Overall, while seamless designs offer advantages in terms of timeline reduction and cost saving, they also present challenges related to additional complexity and the need for efficient surrogate clinical endpoints in oncology drug development.

Influence of Cooling duration on Efficacy in Cardiac Arrest Patients (ICECAP): study protocol for a multicenter, randomized, adaptive allocation clinical trial to identify the optimal duration of induced hypothermia for neuroprotection in comatose, adult survivors of after out-of-hospital cardiac arrest.

Background: Cardiac arrest is a common and devastating emergency of both the heart and brain. More than 380,000 patients suffer out-of-hospital cardiac arrest annually in the United States. Induced cooling of comatose patients markedly improved neurological and functional outcomes in pivotal randomized clinical trials, but the optimal duration of therapeutic hypothermia has not yet been established. Methods: This study is a multi-center randomized, response-adaptive, duration (dose) finding, comparative effectiveness clinical trial with blinded outcome assessment. We investigate two populations of adult comatose survivors of cardiac arrest to ascertain the shortest duration of cooling that provides the maximum treatment effect. The design is based on a statistical model of response as defined by the primary endpoint, a weighted 90-day mRS (modified Rankin Scale, a measure of neurologic disability), across the treatment arms. Subjects will initially be equally randomized between 12, 24, and 48 hours of therapeutic cooling. After the first 200 subjects have been randomized, additional treatment arms between 12 and 48 hours will be opened and patients will be allocated, within each initial cardiac rhythm type (shockable or non-shockable), by response adaptive randomization. As the trial continues, shorter and longer duration arms may be opened. A maximum sample size of 1800 subjects is proposed. Secondary objectives are to characterize: the overall safety and adverse events associated with duration of cooling, the effect on neuropsychological outcomes, and the effect on patient reported quality of life measures. Discussion: In-vitro and in-vivo studies have shown the neuroprotective effects of therapeutic hypothermia for cardiac arrest. We hypothesize that longer durations of cooling may improve either the proportion of patients that attain a good neurological recovery or may result in better recovery among the proportion already categorized as having a good outcome. If the treatment effect of cooling is increasing across duration, for at least some set of durations, then this provides evidence of the efficacy of cooling itself versus normothermia, even in the absence of a normothermia control arm, confirming previous RCTs for OHCA survivors of shockable rhythms and provides the first prospective controlled evidence of efficacy in those without initial shockable rhythms. Trial registration: ClinicalTrials.gov (NCT04217551, 2019-12-30).

An adaptive, phase II, dose-finding clinical trial design to evaluate L-carnitine in the treatment of septic shock based on efficacy and predictive probability of subsequent phase III success.

OBJECTIVES: Sepsis is the tenth leading cause of death in the United States. Despite extensive research, mortality rates for sepsis have not substantially improved in the last several decades. We describe an innovative phase II clinical trial design for evaluating the addition of L-carnitine to the treatment of vasopressor-dependent septic shock. DESIGN: The design incorporates a variety of features to increase efficiency, including a normal dynamic linear dose-response model, adaptive randomization, and early stopping for futility or success based on the probability that a future phase III trial using a 28-day mortality outcome would be successful. SETTING: Trial design and computer simulation of a trial to be conducted in the emergency department and ICU. INTERVENTIONS: Proposed to study intravenous L-carnitine. MEASUREMENTS: The proposed trial uses an early endpoint, the 48-hour change in Sequential Organ Failure Assessment score, to drive adaptive randomization and dose selection. MAIN RESULTS: We use existing data to model the expected relationship between the Sequential Organ Failure Assessment change and the 28-day mortality to determine the trial's operating characteristics using Monte Carlo simulation. CONCLUSIONS: The resulting trial efficiently identifies the best dose of L-carnitine and provides clear guidance regarding whether to continue development into phase III.

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.

Do Bayesian adaptive trials offer advantages for comparative effectiveness research? Protocol for the RE-ADAPT study.

BACKGROUND: Randomized clinical trials, particularly for comparative effectiveness research (CER), are frequently criticized for being overly restrictive or untimely for health-care decision making. PURPOSE: Our prospectively designed REsearch in ADAptive methods for Pragmatic Trials (RE-ADAPT) study is a 'proof of concept' to stimulate investment in Bayesian adaptive designs for future CER trials. METHODS: We will assess whether Bayesian adaptive designs offer potential efficiencies in CER by simulating a re-execution of the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) study using actual data from ALLHAT. RESULTS: We prospectively define seven alternate designs consisting of various combinations of arm dropping, adaptive randomization, and early stopping and describe how these designs will be compared to the original ALLHAT design. We identify the one particular design that would have been executed, which incorporates early stopping and information-based adaptive randomization. LIMITATIONS: While the simulation realistically emulates patient enrollment, interim analyses, and adaptive changes to design, it cannot incorporate key features like the involvement of data monitoring committee in making decisions about adaptive changes. CONCLUSION: This article describes our analytic approach for RE-ADAPT. The next stage of the project is to conduct the re-execution analyses using the seven prespecified designs and the original ALLHAT data.