Browsing by Subject "Clinical trials"
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Item Open Access A new trial design to accelerate tuberculosis drug development: the Phase IIC Selection Trial with Extended Post-treatment follow-up (STEP).(BMC Med, 2016-03-23) Phillips, Patrick PJ; Dooley, Kelly E; Gillespie, Stephen H; Heinrich, Norbert; Stout, Jason E; Nahid, Payam; Diacon, Andreas H; Aarnoutse, Rob E; Kibiki, Gibson S; Boeree, Martin J; Hoelscher, MichaelBACKGROUND: The standard 6-month four-drug regimen for the treatment of drug-sensitive tuberculosis has remained unchanged for decades and is inadequate to control the epidemic. Shorter, simpler regimens are urgently needed to defeat what is now the world's greatest infectious disease killer. METHODS: We describe the Phase IIC Selection Trial with Extended Post-treatment follow-up (STEP) as a novel hybrid phase II/III trial design to accelerate regimen development. In the Phase IIC STEP trial, the experimental regimen is given for the duration for which it will be studied in phase III (presently 3 or 4 months) and patients are followed for clinical outcomes of treatment failure and relapse for a total of 12 months from randomisation. Operating characteristics of the trial design are explored assuming a classical frequentist framework as well as a Bayesian framework with flat and sceptical priors. A simulation study is conducted using data from the RIFAQUIN phase III trial to illustrate how such a design could be used in practice. RESULTS: With 80 patients per arm, and two (2.5 %) unfavourable outcomes in the STEP trial, there is a probability of 0.99 that the proportion of unfavourable outcomes in a potential phase III trial would be less than 12 % and a probability of 0.91 that the proportion of unfavourable outcomes would be less than 8 %. With six (7.5 %) unfavourable outcomes, there is a probability of 0.82 that the proportion of unfavourable outcomes in a potential phase III trial would be less than 12 % and a probability of 0.41 that it would be less than 8 %. Simulations using data from the RIFAQUIN trial show that a STEP trial with 80 patients per arm would have correctly shown that the Inferior Regimen should not proceed to phase III and would have had a high chance (0.88) of either showing that the Successful Regimen could proceed to phase III or that it might require further optimisation. CONCLUSIONS: Collection of definitive clinical outcome data in a relatively small number of participants over only 12 months provides valuable information about the likelihood of success in a future phase III trial. We strongly believe that the STEP trial design described herein is an important tool that would allow for more informed decision-making and accelerate regimen development.Item Embargo Design and Analysis of Clinical Trials with Restricted Mean Survival Time(2024) Hua, KaiyuanRestricted mean survival time (RMST), a summary of survival time up to a pre-specified clinically relevant truncation time, is increasingly recognized as a measure for treatment effect in recent biomedical studies with time-to-event endpoints. The difference or ratio of RMST between two groups (e.g., treatment versus control) measures the relative treatment effect concerning a gain or loss of survival time. The RMST offers greater flexibility than the hazard ratio (HR), which is often estimated from the Cox proportional hazards model under the proportional hazards (PH) assumption. Due to delayed treatment effects or other biomedical reasons, the PH assumption is often violated in oncology and cardiovascular trials, leading to biased estimation and misleading interpretations of treatment effects. Compared to HR, RMST requires no PH assumption and offers a more straightforward interpretation of treatment effects. In this dissertation, we propose novel RMST-based methodologies for clinical trials with time-to-event endpoints in three research areas including 1) individual participant data network meta-analysis, 2) inference in multi-regional clinical trials, and 3) biomarker-guided adaptive and enrichment design.
Item Open Access Identifying Barriers and Practical Solutions to Conducting Site-Based Research in North America: Exploring Acute Heart Failure Trials As a Case Study.(Heart Fail Clin, 2015-10) Ambrosy, Andrew P; Mentz, Robert J; Krishnamoorthy, Arun; Greene, Stephen J; Severance, Harry WAlthough the prognosis of ambulatory heart failure (HF) has improved dramatically there have been few advances in the management of acute HF (AHF). Despite regional differences in patient characteristics, background therapy, and event rates, AHF clinical trial enrollment has transitioned from North America and Western Europe to Eastern Europe, South America, and Asia-Pacific where regulatory burden and cost of conducting research may be less prohibitive. It is unclear if the results of clinical trials conducted outside of North America are generalizable to US patient populations. This article uses AHF as a paradigm and identifies barriers and practical solutions to successfully conducting site-based research in North America.Item Open Access Methods for a multicenter randomized trial for mixed urinary incontinence: rationale and patient-centeredness of the ESTEEM trial.(Int Urogynecol J, 2016-10) Sung, Vivian W; Borello-France, Diane; Dunivan, Gena; Gantz, Marie; Lukacz, Emily S; Moalli, Pamela; Newman, Diane K; Richter, Holly E; Ridgeway, Beri; Smith, Ariana L; Weidner, Alison C; Meikle, Susan; Pelvic Floor Disorders NetworkINTRODUCTION AND HYPOTHESIS: Mixed urinary incontinence (MUI) can be a challenging condition to manage. We describe the protocol design and rationale for the Effects of Surgical Treatment Enhanced with Exercise for Mixed Urinary Incontinence (ESTEEM) trial, designed to compare a combined conservative and surgical treatment approach versus surgery alone for improving patient-centered MUI outcomes at 12 months. METHODS: ESTEEM is a multisite, prospective, randomized trial of female participants with MUI randomized to a standardized perioperative behavioral/pelvic floor exercise intervention plus midurethral sling versus midurethral sling alone. We describe our methods and four challenges encountered during the design phase: defining the study population, selecting relevant patient-centered outcomes, determining sample size estimates using a patient-reported outcome measure, and designing an analysis plan that accommodates MUI failure rates. A central theme in the design was patient centeredness, which guided many key decisions. Our primary outcome is patient-reported MUI symptoms measured using the Urogenital Distress Inventory (UDI) score at 12 months. Secondary outcomes include quality of life, sexual function, cost-effectiveness, time to failure, and need for additional treatment. RESULTS: The final study design was implemented in November 2013 across eight clinical sites in the Pelvic Floor Disorders Network. As of 27 February 2016, 433 total/472 targeted participants had been randomized. CONCLUSIONS: We describe the ESTEEM protocol and our methods for reaching consensus for methodological challenges in designing a trial for MUI by maintaining the patient perspective at the core of key decisions. This trial will provide information that can directly impact patient care and clinical decision making.Item Open Access Periodic benefit-risk assessment using Bayesian stochastic multi-criteria acceptability analysis.(Contemporary clinical trials, 2018-04) Li, Kan; Yuan, Shuai Sammy; Wang, William; Wan, Shuyan Sabrina; Ceesay, Paulette; Heyse, Joseph F; Mt-Isa, Shahrul; Luo, ShengBenefit-risk (BR) assessment is essential to ensure the best decisions are made for a medical product in the clinical development process, regulatory marketing authorization, post-market surveillance, and coverage and reimbursement decisions. One challenge of BR assessment in practice is that the benefit and risk profile may keep evolving while new evidence is accumulating. Regulators and the International Conference on Harmonization (ICH) recommend performing periodic benefit-risk evaluation report (PBRER) through the product's lifecycle. In this paper, we propose a general statistical framework for periodic benefit-risk assessment, in which Bayesian meta-analysis and stochastic multi-criteria acceptability analysis (SMAA) will be combined to synthesize the accumulating evidence. The proposed approach allows us to compare the acceptability of different drugs dynamically and effectively and accounts for the uncertainty of clinical measurements and imprecise or incomplete preference information of decision makers. We apply our approaches to two real examples in a post-hoc way for illustration purpose. The proposed method may easily be modified for other pre and post market settings, and thus be an important complement to the current structured benefit-risk assessment (sBRA) framework to improve the transparent and consistency of the decision-making process.Item Open Access The Impact of Worsening Heart Failure in the United States.(Heart Fail Clin, 2015-10) Cooper, Lauren B; DeVore, Adam D; Michael Felker, GIn-hospital worsening heart failure represents a clinical scenario wherein a patient hospitalized for acute heart failure experiences a worsening of their condition, requiring escalation of therapy. Worsening heart failure is associated with worse in-hospital and postdischarge outcomes. Worsening heart failure is increasingly being used as an endpoint or combined endpoint in clinical trials, as it is unique to episodes of acute heart failure and captures an important event during the inpatient course. While prediction models have been developed to identify worsening heart failure, there are no known FDA-approved medications associated with decreased worsening heart failure. Continued study is warranted.